Patent Publication Number: US-2013252227-A1

Title: Apparatus and Method for Providing Cryopreserved ECP-Treated Mononuclear Cells

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates to an apparatus and methods for providing cryopreserved mononuclear cells that have been treated by extracorporeal photopheresis (“ECP”). More particularly, the present disclosure relates to apparatus and methods for providing ECP-treated mononuclear cells that retain their apoptotic properties after cryopreservation and subsequent thawing. 
     BACKGROUND 
     Whole blood is made up of various cellular and non-cellular components such as red cells, white cells and platelets suspended in its liquid component, plasma. The administration of blood and/or blood components is common in the treatment of patients suffering from disease. Rather than infuse whole blood, it is more typical that individual components be administered to the patient as their needs require. For example, administration (infusion) of platelets is often prescribed for cancer patients whose ability to make platelets has been compromised by chemotherapy. Infusion of white blood cells (e.g. mononuclear cells), after the cells have undergone some additional processing or treatment, for example, to activate the mononuclear cells, may also be prescribed for therapeutic reasons including treatment of diseases that may involve the white blood cells. Thus, it is often desirable to separate and collect the desired blood component from whole blood and then treat the patient with the specific blood component. The remaining components may be returned to the donor or retained for other uses. 
     There are several diseases or disorders which are believed to primarily involve mononuclear cells, such as cutaneous T-cell lymphoma, organ allograft rejection after transplantation, graft versus host disease and autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, among others, as described below. 
     Cutaneous T-cell lymphoma (CTCL) is a term that is used to describe a wide variety of disorders. Generally, CTCL is a type of cancer of the immune system where T-cells (a type of mononuclear cell) mutate or grow in an uncontrolled way, migrate to the skin and form itchy, scaly plaques or patches. More advanced stages of the disease also affect the lymph nodes. Therapeutic treatment options for CTCL have previously been limited. While chemotherapy has been utilized, this particular form of treatment also has many associated undesirable side effects such as lowered resistance to infection, bleeding, bruising, nausea, infertility and hair loss, just to name a few. 
     Organ allograft rejection may be characterized as the rejection of tissues that are foreign to a host, including transplanted cardiac tissue as well as lung, liver and renal transplants. Immunosuppression drug therapy following transplantation is common. However, there are potential drawbacks including recurring infection due to the compromised competence of the immune system caused by this type of therapy. 
     Similarly, graft versus host disease (GVHD) is a complication that can occur after a stem cell or bone marrow transplant in which the newly transplanted material attacks the transplant recipient&#39;s body. The differences between the donor&#39;s cells and recipient&#39;s tissues often cause T-cells from the donor to recognize the recipient&#39;s body tissues as foreign, thereby causing the newly transplanted cells to attack the recipient. GVHD may complicate stem cell or bone marrow transplantation, thereby potentially limiting these life-saving therapies. Therefore, after a transplant, the recipient is usually administered a drug that suppresses the immune system, which helps reduce the chances or severity of GVHD. See Dugdale, David C., et al. “Graft-Versus-Host Disease,”  MedlinePlus A.D.A.M Medical Encyclopedia , Updated Jun. 2, 2010. 
     Autoimmune diseases, including rheumatoid arthritis (RA) and progressive systemic sclerosis (PSS), can be characterized by an overactive immune system which mistakes the body&#39;s own tissues as being a foreign substance. As a result, the body makes autoantibodies that attack normal cells and tissues. At the same time, regulatory T-cells, which normally function to regulate the immune system and suppress excessive reactions or autoimmunity, fail in this capacity. This may lead to, among other things, joint destruction in RA and inflammation of the connective tissue in PSS. 
     Where existing therapies for treating one or more diseases may result in certain unintended side effects, additional treatment may be desired or required. One known procedure which has been shown to be effective in the treatment of diseases and/or the side effects of existing therapies is extracorporeal photopheresis or “ECP”. Extracorporeal photopheresis (also sometimes referred to as extracorporeal photochemotherapy) is a process that includes: (1) collection of mononuclear cells “MNC” from a patient, (2) photoactivation treatment of the collected mononuclear cells, and (3) reinfusion of the treated mononuclear cells back to the patient. More specifically, ECP involves the extracorporeal exposure of peripheral blood mononuclear cells combined with a photoactive compound, such as 8-methoxypsoralen or “8-MOP” which is then photoactivated by ultraviolet light, followed by the reinfusion of the treated mononuclear cells. It is believed that the combination of 8-MOP and UV radiation encourages and/or causes apoptosis or programmed cell death (also referred to herein as the “apoptosis trend”) of ECP-treated cells. 
     Although the precise mechanism of action in ECP treatment (in the different disease states) is not fully known, according to early theories, it was believed that photoactivation causes 8-MOP to irreversibly covalently bind to the DNA strands contained in the T-cell nucleus. When the photochemically damaged T-cells are reinfused, cytotoxic effects are induced. For example, a cytotoxic T-cell or “CD8+ cell” releases cytotoxins when exposed to infected or damaged cells or otherwise attacks cells carrying certain foreign or abnormal molecules on their surfaces. The cytotoxins target the damaged cell&#39;s membrane and enter the target cell, which eventually leads to apoptosis or programmed cell death of the targeted cell. In other words, after the treated mononuclear cells are returned to the body, the immune system recognizes the dying abnormal cells and begins to produce healthy lymphocytes (T-cells) to fight against those cells. 
     In addition to the above, it has also been theorized that extracorporeal photopheresis also induces monocytes (a type of mononuclear cell) to differentiate into dendritic cells capable of phagocytosing and processing the apoptotic T-cell antigens. When these activated dendritic cells are re-infused into systemic circulation, they may cause a systemic cytotoxic CD8+ T-lymphocyte-mediated immune response to the processed apoptotic T-cell antigens like that described above. It will be appreciated that other possible mechanisms of action may be involved in achieving the benefits that have been observed from the ECP treatment of mononuclear cells and the subsequent benefits to patients undergoing ECP based therapies. 
     More recently, it has been postulated that ECP may result in an immune tolerant response in the patient. For example, in the case of graft versus-host disease, the infusion of apoptotic cells may stimulate regulatory T-cell generation, inhibit inflammatory cytokine production, cause the deletion of effective T-cells and result in other responses. See Peritt, “Potential Mechanisms of Photopheresis in Hematopoietic Stem Cell Transplantation,”  Biology of Blood and Marrow Transplantation  12:7-12 (2006). While presently the theory of an immune tolerant response appears to be among the leading explanations, there exists other theories as to the mechanism of action of ECP relative to graft-versus-host disease, as well as other disease states. 
     In any event, it will be appreciated that ECP treatment directly promotes and encourages apoptosis of lymphocytes following exposure to UV light. Regardless of the precise mechanism of action, it is presently understood that apoptosis plays a role in the therapeutic properties achieved, and beneficial clinical effects of, ECP treatment. 
     Currently, known ECP treatment procedures (i.e. the apheresis collection of a mononuclear cell product from a patient, the addition of 8-MOP to the collected cell product, subsequent UV irradiation and the reinfusion of the treated mononuclear cell product) may be performed on two or more consecutive days on a weekly basis, the frequency depending on the state of the particular disease being treated and/or the patient&#39;s response to the treatment. Systems for performing ECP include, for example, the UVAR XTS Photopheresis System developed by Therakos, Inc., of Exton, Pa. Further details of the Therakos system can be found, for example, in U.S. Pat. No. 5,984,887. 
     While the clinical benefits of ECP have been recognized, the use of ECP may be limited by logistical difficulties, including the need to repeatedly perform apheresis collections of mononuclear cells. Further, while methods for the cryopreservation of mononuclear cells prior to such ECP treatment has been described (see, for example, Merlin, E., et al. “Cryopreservation of mononuclear cells before extracorporeal photochemotherapy does not impair their anti-proliferative capabilities.”  Cytotherapy  2011; 13:248-255), these methods would still require a physician or other clinician to perform the multiple steps of ECP treatment, including combining mononuclear cells with 8-MOP and irradiating the cells with UV light, each time the cryopreserved cells are thawed in order to obtain one or more therapeutic portions of ECP treated cells for re-infusion to a patient. 
     The ability to cryopreserve substantially all, or a portion of, mononuclear cell products derived from an extracorporeal photopheresis treatment as described herein addresses these and other drawbacks. For example, the disclosed apparatus and methods would allow for one or multiple portions of ECP treated mononuclear cell products to be collected from a single apheresis and photopheresis session, and/or allow the collected portions of ECP treated mononuclear cell products to be divided into smaller portions for more (or less) frequent administration while saving a patient from the burden of undergoing multiple or additional apheresis collections. It would also relieve the clinician from having to repeat the ECP treatment procedure each time cryopreserved untreated mononuclear cell products are thawed. 
     Therefore, it would be desirable to develop an apparatus and methods for storing an ECP-treated mononuclear cell product, such as by cryopreservation, which does not significantly affect the apoptosis trend of lymphocytes and/or other therapeutic properties or clinical benefits of ECP-based therapy after cryopreservation and the subsequent thawing. The steps of an ECP procedure would have to be performed less frequently, while allowing one or more therapeutic portions of cyropreserved ECP treated cell products to be obtained which may later be thawed and re-infused to a patient as part of a disease treatment protocol. 
     SUMMARY 
     In one aspect, the present disclosure is directed to a method of providing a cryopreserved treated mononuclear cell product. The method includes combining a mononuclear cell product with a photoactive compound that is activated by exposure to light of a selected wavelength. The mononuclear cell product combined with photoactive compound is then exposed to light for a selected period of time at the selected wavelength to obtain a treated mononuclear cell product. The method further includes combining at least a portion of the treated product with a cryopreservation medium and cryopreserving at least the portion of the treated mononuclear cell product. 
     In another aspect, the present disclosure is directed to a cryopreserved treated mononuclear cell product. The treated product includes about 50 mL to about 300 mL of a mononuclear cell product that has been exposed to a selected dose of ultraviolet light and about 50 mL to about 300 mL of a cryopreservation solution. In one embodiment, the mononuclear cell product is combined with a photoactive compound including 8-methoxypsoralen prior to exposure to ultraviolet light. In one embodiment, the mononuclear cell product comprises about 100-300 nanograms/mL of a photoactive compound prior to exposure to ultraviolet light. 
     In yet another aspect, the present disclosure is directed to a method of providing a treated mononuclear cell product. The method includes providing a mononuclear cell product and combining the cell product with a photoactive compound. The method further includes exposing the combined cell product to ultraviolet light to obtain a treated mononuclear cell product. At least a portion of the treated mononuclear cell product is cryopreserved for a selected period of time. Finally, the method includes thawing a selected amount of the cryopreserved treated cell product. In another aspect, a treated mononuclear cell product prepared in accordance with the aforementioned method is disclosed. In one embodiment, this thawed selected amount of treated mononuclear cell product includes at least one therapeutic portion of mononuclear cells suitable for administration to a patient and is effective in the treatment of disease comprising, for example, cutaneous T-cell lymphoma, organ allograft rejection after transplantation, graft versus host disease, rheumatoid arthritis and systemic sclerosis. In another embodiment, the thawed selected amount of treated mononuclear cells is suitable for the treatment of side effects of existing therapies involving mononuclear cells. 
     In a further aspect, a method for treating a patient suffering from a disease is disclosed. The method includes collecting a mononuclear cell product, combining the cell product with an activation agent and exposing the cell product combined with agent to light to obtain a treated cell product. The method further includes adding a cryopreservation agent to the treated cell product and then cryopreserving the treated product. At least a portion of the cryopreserved treated cell product may be thawed and administered to a patient. 
     In another aspect, the present disclosure is directed to an apparatus for providing mononuclear cells that have been treated by extracorporeal photopheresis. The apparatus includes a disposable fluid circuit that has a processing chamber for separating whole blood into one or more components including mononuclear cells, at least one auxiliary storage container and optionally, a source of cryopreservation solution. The apparatus further includes a separation device adapted to receive the processing chamber for effecting separation of mononuclear cells from whole blood. The apparatus also includes at least one programmable controller that is programmed to separate mononuclear cells from whole blood and irradiate the cells with ultraviolet light to produce treated mononuclear cells and may optionally be programmed to combine the treated cells with cryopreservation solution. The controller may also be programmed to convey at least a portion of the treated cells that are combined with cryopreservation solution into the auxiliary storage container for cryopreservation therein. In one embodiment, the disposable fluid circuit may further include a source of 8-methoxypsoralen and/or a port adapted for introducing 8-methoxypsoralen into the fluid circuit and the controller may be further programmed to combine 8-methoxypsoralen with mononuclear cells prior to irradiating the cells with ultraviolet light. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram generally showing the mechanical components of an extracorporeal photopheresis treatment as described herein; 
         FIG. 2  is a flow chart setting forth the steps of the method of a photopheresis treatment including cryopreservation and thawing as described herein; 
         FIG. 3  is a partial perspective view of a separator useful in the methods and apparatus described herein; 
         FIG. 4  is a diagram of the fluid circuit useful in the collection, treatment and cryopreservation of mononuclear cells as described herein; and 
         FIG. 5  graphically illustrates the apoptosis trend of both fresh and cryopreserved/thawed ECP treated cells over a selected period of time. 
         FIG. 6  graphically illustrates the apoptosis trend of both fresh and cryopreserved/thawed ECP treated cells over a selected period of time. 
     
    
    
     DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     The subject matter of the present disclosure relates generally to apparatus and methods for providing cryopreserved mononuclear cell products that have been treated by extracorporeal photopheresis (ECP). The cryopreserved treated mononuclear cell product may be thawed as needed for later reinfusion. As described herein, the therapeutic properties of the treated cell product is not significantly affected by cryopreservation or subsequent thawing. 
     The term therapeutic properties as used herein includes, but is not limited to, the encouraged apoptosis or apoptosis trend of ECP treated cells, as described in further detail below. It will be appreciated that at least the apoptosis trend of cells treated in accordance with the apparatus and methods described herein is not significantly affected. “Not significantly affected” shall be understood to mean wherein the percentage of apoptotic cells of a given sample or therapeutic portion of mononuclear cells after ECP treatment, cryopreservation and subsequent thawing, is within ±20% of the percentage of apoptotic cells of a sample or therapeutic portion of fresh (i.e. non-cryopreserved) ECP-treated cells over a given period of time. In other words, the percentage of apoptotic mononuclear cells following treatment in accordance with the disclosed apparatus and methods remains within 20% of ECP treated cells that are not subjected to cryopreservation and/or thawing over a selected period of time. If desired, it may be determined what percentage of cells have undergone apoptosis by performing certain tests on selected samples of treated and/or untreated cells as illustrated in Exemplary  FIGS. 5 and 6  and as described in Examples A and B set forth below. 
     Turning now to one embodiment of the apparatus and methods described herein, mononuclear cells are provided. As used herein, “mononuclear cells” may also be referred to as “mononuclear cell product” or “MNC product”. This may be accomplished by withdrawing whole blood from a patient, such as by an intravenous line or the like, and separating a mononuclear cell product from the whole blood by automated apheresis, centrifugation or other known automated or manual separation techniques. The mononuclear cell product may also be obtained from previously collected blood stored in a package, container or bag. 
     With regard to apheresis, the device in which the separation of blood occurs may include a centrifuge to provide a cell product comprising at least white blood cells. Non-limiting examples of apheresis devices that may be used to separate mononuclear cells from blood include the Alyx Separator and the Amicus® Separator made and sold by Fenwal, Inc. of Lake Zurich, Ill. One example of an apparatus and method of collecting mononuclear cells is provided in U.S. Pat. No. 6,027,657 which is incorporated by reference herein. With regard to manual collection, whole blood may be collected in a bag or container and separated, such as by centrifugation, into its various component parts, including, for example, red blood cells, plasma (which may or may not contain platelets) and white blood cells. White blood cells may be retained in the bag while the remaining blood components can be manually expressed from the bag such as by squeezing or manipulation of the bag. It will be appreciated that white blood cells may also be obtained by bone marrow processing and/or from cord blood. 
       FIG. 1  shows, in general, the mechanical components that make up the exemplary apparatus and that are used in the methods described herein. In accordance with the present disclosure, the apparatus preferably includes a separation component  10  and a treatment (i.e., irradiation) component  20 . A patient is connected to separation component  10  via a blood processing set, i.e., fluid circuit  200 . With reference to  FIG. 1 , whole blood is withdrawn from the patient and introduced into the separation component  10  where the whole blood is separated to provide a target cell population. In a preferred embodiment in accordance with the present disclosure, the target cell population may be a mononuclear cell product. Other components separated from the whole blood, such as red blood cells and platelets may be returned to the patient or collected in pre-attached containers of the blood processing set  200  for storage or further processing. 
     Briefly,  FIGS. 3-4  show a representative blood centrifuge  10  with fluid circuit  200  mounted thereon, the fluid circuit ( FIG. 4 ) having a blood processing container  14  defining a separation chamber  12  suitable for harvesting a mononuclear cell product from whole blood. As shown in  FIG. 3 , a disposable processing set or fluid circuit  200  (which includes container  14 ) is mounted on the front panel of centrifuge  10 . The processing set (fluid circuit  200 ) includes a plurality of processing cassettes  23 L,  23 M and  23 R with tubing loops for association with peristaltic pumps PSL, PSM and PSR on device  10 . Fluid circuit  200  also includes a network of tubing and pre-connected containers for establishing flow communication with the patient and for processing and collecting fluids and blood and blood components, as shown in greater detail in  FIG. 4 . As seen in  FIGS. 3 and 4 , disposable processing set  200  may include a container  60  for supplying anticoagulant, a waste container  62  (see  FIG. 4 ) for collecting waste from one or more steps in the process for treating and washing mononuclear cells, a container  64  for holding saline or other wash or resuspension medium, a container  66  for collecting plasma and one or more container(s)  68  for collecting, illuminating and/or cryopreserving the mononuclear cell product. Additional containers may be provided, for example, including a container  84  for holding a cryopreservation medium and/or a container  86  for holding a photoactive compound such as 8-MOP. Such containers may be integral with the fluid circuit  200  or provided separately. 
     With reference to  FIG. 4 , fluid circuit includes inlet line  72 , an anticoagulant (AC) line  74  for delivering AC from container  60 , an RBC line  76  for conveying red blood cells from separation chamber  12  of container  14  to container  67 , a platelet-poor plasma (PPP) line  78  for conveying PPP to container  66  and line  80  for conveying mononuclear cells to and from separation chamber  12  and collection/illumination/cryopreservation container  68 . As will be known to those of skill in the art, the blood processing set includes one or more venipuncture needle(s) for accessing the circulatory system of the patient. As shown in  FIG. 4 , fluid circuit  200  includes inlet needle  70  and return needle  82 . In an alternative embodiment, a single needle can serve as both the inlet and outlet needle. 
     Fluid flow through fluid circuit  200  is preferably driven, controlled and adjusted by one or more microprocessor-based controllers in cooperation with the valves, pumps, weight scales and sensors of device  10  and fluid circuit  200 , the details of which are described in the previously mentioned U.S. Pat. No. 6,027,657. In one embodiment, the controller can be programmed to control various operations performed by the apparatus or device  10  disclosed herein. For example, the controller may be programmed to separate mononuclear cells from whole blood within the separation chamber  12  of the fluid circuit  200 , combine the separated mononuclear cell product with a photoactive compound, irradiate mononuclear cell product with ultraviolet light in an illumination device  20  (which device may be associated with separation component  10  or separately provided therefrom) and/or combine the treated mononuclear cell product with a cryopreservation solution after irradiation. It will be appreciated that the controller may also be programmed to perform additional processing and treatment steps as necessary or desired. 
     Collection of the mononuclear cell product may proceed in one or more cycles. The number of processing cycles conducted in a given therapeutic procedure will depend upon the total desired amount or portion of MNC to be collected. For example, in a representative procedure, five collection cycles may be performed sequentially. During each cycle about 1500-3000 ml of whole blood can be processed, obtaining a MNC product volume of about 3 ml per cycle and a total volume of 15 ml of MNC product. As shown in step  32  of  FIG. 2 , the final volume of collected mononuclear cell product is then provided for further treatment in accordance with the present disclosure. Of course, the collection of the MNC product is not limited to the method described above. MNCs may be collected in any manner known to those of skill in the art. 
     Effective treatment of the mononuclear cell product with light may require that the amount of collected mononuclear cells have a suitable hematocrit. Thus, it may be desired or even necessary to dilute the mononuclear cell product with a diluting solution such as plasma or saline, as shown in step  33 . In the example described above, approximately 15 ml of MNC product may be diluted in an amount of plasma having a volume of about 1-300 ml and more preferably about 150 ml of plasma. 
     The diluted mononuclear cell product (in container  68 ) is then combined with the suitable photoactivation agent in step  34 . As discussed above, for ECP treatment, the compound 8-methoxypsoralen (8-MOP) has been shown to be an effective photoactivation agent, however, other suitable photoactivation agents may be used, including, for example, a psoralen compound. It will be appreciated that mononuclear cell product may be combined with a photosensitive compound in any amount effective for satisfactorily treating cells by ECP. In one example, 8-MOP is combined with the collected and diluted mononuclear cell product to arrive at a mixture having a final 8-MOP concentration of 200 nanograms/mL and/or any suitable effective amount. Typically, the mononuclear cell product may be combined with the photoactivation agent to arrive at a final 8-MOP concentration in a range of about 100 to 300 nanograms/mL. 
     The combination of 8-MOP and mononuclear cells can be accomplished by in vitro methods, such as by combining 8-MOP with a mononuclear cell product that has been collected by apheresis. In one example, the fluid circuit  200  (in which mononuclear cells are separated from whole blood) may include a source of 8-MOP in container  86 . The 8-MOP or other photoactivation agent may be added directly to container  68  or added elsewhere into the fluid circuit  200 , either manually by a syringe and/or under the direction of the microprocessor-based controller, which may be programmed to automatically deliver the desired amount of photoactive agent before, during, or after the MNC product collection, based on the volume of MNC product collected or to be collected. Alternatively, the desired volume of the agent may be pre-added to the container  68 . 
     Alternatively, 8-MOP may be administered to a patient before whole blood is drawn and processed to separate mononuclear cells. In this method, 8-MOP may be administered in vivo, such as orally or intravenously. A portion of the blood from a patient to which 8-MOP has been administered may then be withdrawn and mononuclear cells separated therefrom. 
     Regardless of whether the mononuclear cell product and 8-MOP are combined in vivo or in vitro, the resulting combination of mononuclear cell product mixed with 8-MOP is preferably then exposed to or irradiated with light as shown in step  36  of  FIG. 2 . As noted above, the mononuclear cell product collected in accordance with the collection process described above may be collected in container  68  that is suitable for irradiation by light of a selected wavelength. By “suitable” it is meant that the walls of the container are sufficiently transparent to light of the selected wavelength to activate the photoactive agent. In treatments using UVA light, for example, container walls made of ethylene vinyl acetate (EVA) are suitable. 
     Accordingly, container  68  in which the mononuclear cell product is collected may serve both as the collection container and the irradiation container. Container  68  may be placed inside irradiation device  20  by the operator or more preferably, may be placed inside the irradiation chamber of irradiation device  20  at the beginning of the ECP procedure and prior to whole blood withdrawal (as shown by the broken lines representing device  20  in  FIG. 4 ). In any event, container  68  may remain integrally connected to the remainder of fluid circuit  200  during the entire procedure, thereby maintaining the closed or functionally closed condition of fluid circuit  200 . Alternatively, container  68  may be disconnected after mononuclear cell collection has been completed but before 8-MOP is added to the mononuclear cell product in container  68 . 
     As noted above, the fluid circuit  200  is adapted for association with the treatment component (i.e., irradiation device)  20 . It will also be appreciated, however, that the irradiation device does not have to be integral or even associated with the fluid circuit  200  and/or separation device  10 . In fact, the irradiation device  20  may be in an entirely separate location from the separation device and/or circuit, such as a location in an entirely different room or building. In such a case, container  68  may be disconnected after collection has been completed for the later addition of 8-MOP to the mononuclear cell product in container  68  and/or irradiation of the container in one or more different locations. 
     One known apparatus suitable for the irradiation of mononuclear cells is available from sources such as Cerus Corporation, of Concord, Calif., such as, for example the irradiation device described in U.S. Pat. No. 7,433,030, the contents of which is likewise incorporated by reference herein in its entirety. As shown and described in U.S. Pat. No. 7,433,030, irradiation device  20  preferably includes a tray or other holder for receiving one or more containers during treatment. Other irradiation devices may also be suitable for use with the method and apparatus described herein. However, it is also contemplated that suitable irradiation may also be accomplished by any source of ultraviolet light which provides UV light at a selected UVA dose, including natural sunlight. 
     Regardless of the type of irradiation device and/or the source of UV light, the mononuclear cell product combined with photoactivation agent (8-MOP) is irradiated for a selected UVA dose. In one non-limiting example, during treatment, the mononuclear cell product may be exposed to UV bulbs having a UVA wavelength in the UVA range of about 320 nm to 400 nm for a selected period of time, such as approximately 10-60 minutes, resulting in an average UVA exposure of approximately 0.5-5.0 J/cm 2  and preferably approximately 1-2 J/cm 2  or even more preferably approximately 1.5 J/cm2 per lymphocyte. As illustrated in  FIG. 2 , following UV light exposure or irradiation of the mononuclear cell product combined with 8-MOP, the freshly treated cell product, or a portion thereof, may then be returned to the patient as illustrated by reference numeral  40 . 
     It will be appreciated that the volume of mononuclear cell product obtained from a single apheresis collection and subsequently treated by extracorporeal photopheresis may provide more than one therapeutic portion of an ECP-treated mononuclear cell product. Accordingly, once a portion of freshly ECP treated mononuclear cell product is administered to a patient, there may be one or more portions of freshly treated mononuclear cell products remaining. 
     In accordance with the apparatus and methods described herein and as shown by step  44  in  FIG. 2 , it is preferable to cryopreserve any portion of freshly treated cells that remain after a selected portion of freshly treated cells are administered to a patient. Alternatively, if none of the freshly ECP-treated cells are reinfused, then all of the freshly treated cells may preferably be cryopreserved in one or multiple separate containers for one or more future treatment sessions. Preferably, the ECP-treated cells are preserved by cooling to low sub-zero temperatures, such as by cryopreservation techniques at a temperature range of about −80° C. to −200° C. for example. 
     The cryopreservation of one or more portions of ECP-treated cells provides several advantages. For example, a typical ECP therapy schedule can be maintained (i.e. reinfusion of ECP-treated cells on one or more consecutive days) while reducing the number of repeated apheresis collections and UV irradiation procedures that must be performed. Another advantage is that ECP treated MNCs can be split or otherwise separated into smaller portions before cryopreservation and/or after thawing which can be administered more (or less) frequently, without subjecting the patient to an increased number of MNC collection procedures. 
     In accordance with the methods described herein, the ECP-treated mononuclear cell product is preferably combined with a cryoprotectant solution or freezing media as illustrated by step  42  in  FIG. 2 . In one embodiment, the treated mononuclear cell product and cryoprotectant is preferably combined in a ratio of 1:1. Any media suitable for the cryopreservation of mononuclear cells may be used. In one example, the cryopreservation media may contain human serum albumin, DMSO and/or starch. It will also be appreciated that the treated mononuclear cell product may optionally be combined with preservative and/or storage solutions including, but not limited to solutions containing bicarbonate, acetate, phosphate and/or citrate. Such solutions include RPMI developed by Moore et. al. at Roswell Park Memorial Institute and PAS V manufactured by Fenwal, Inc. The cryopreservation media and/or other preservative/storage solution may be added to the ECP-treated mononuclear cell product before (or contemporaneously with) conveying the treated cell product to a suitable cryopreservation container  68 . Alternatively, the media may be added to the cells after they have been conveyed into one or more cryopreservation container(s)  68 . 
     In one embodiment as shown in  FIG. 4  fluid circuit  200  may include a source of cryopreservation media in, for example, container  84  in openable fluid communication with the circuit, such that cryopreservation media can be added directly to or combined with the treated mononuclear cell product in separation chamber  12  and/or in container(s)  68  or added elsewhere into the fluid circuit  200  either manually by a syringe and/or under the direction of the microprocessor-based controller which may be programmed to automatically deliver the desired amount of cryopreservation media. After being combined with cryopreservation media and/or a storage solution, the treated cell product is then cryopreserved in the one or more respective cryopreservation containers  68 . In one example, container(s)  68  may be Cryocyte freezing bags sold by Baxter Healthcare of Deerfield, Ill. 
     It will be appreciated that any known method suitable for the cryopreservation of a mononuclear cell product may be used. One such exemplary method of cryopreservation is described in Halle et al. “Uncontrolled-rate freezing and storage at −80° C., with only 3.5-percent DMSO in cryoprotective solution for 109 autologous peripheral blood progenitor cell transplantations”,  Transfusion , vol. 41, May 2001, which is incorporated herein by reference in its entirety. 
     The treated MNC product may be cryopreserved for a selected period of time, ranging anywhere from several hours to several weeks or longer, up until a time when they are needed. In one example, the treated MNC product may be cryopreserved for one week, at which time a selected volume of treated cells, such as an amount sufficient to constitute a single therapeutic portion, is thawed as illustrated in  FIG. 2 , step  48 , for administration to a patient. Of course, it will be appreciated that any desired amount of cryopreserved ECP-treated mononuclear cells may be thawed, as needed, for a particular therapeutic or treatment protocol. 
     Any suitable methods for thawing the treated cryopreserved mononuclear cell product may be used, including the procedure described in Halle et al., referenced above. In one example, the treated mononuclear cell product may be thawed rapidly in a 37° C. water bath. It may be desirable to add a thawing media to the treated cell product during the thawing procedure. In one embodiment of the described method, the thawed ECP treated cells are suitable for immediate re-infusion to the patient. Alternatively, it is also contemplated that the thawed ECP-treated MNC product may be further processed before reinfusion. 
     In one embodiment, as shown in broken lines in step  50   FIG. 2 , such additional processing may include the optional washing of the treated MNC product prior to reinfusion. It may be desirable to wash the treated cells for several reasons, such as to remove photoactive agent and/or cryopreservation media from the treated mononuclear cells. More specifically, during photopheresis, MNCs are incubated with a photoactive agent such as 8-MOP. Exposure of 8-MOP to (ultraviolet) light crosslinks the 8-MOP to the DNA and other proteins of MNCs, eventually resulting in cell apoptosis. However, not all of the 8-MOP crosslinks to the DNA of the MNCs. Some of the 8-MOP remains unbound and is infused to the patient with the treated cells. Excess (and unbound) 8-MOP is distributed throughout the body, making the patient especially sensitive to UV light exposure, particularly through the eyes. Therefore, as illustrated in  FIG. 2 , it may be desirable to wash the ECP-treated MNC product to remove any excess and unbound photoactive agent from the treated MNC product prior to reinfusion, either before the treated cells are cryopreserved or after they are thawed. Other reasons for washing the treated MNC product prior to reinfusion to a patient may include to remove any storage or cryopreservation media that may have been added to the treated cell product prior to freezing. 
     Washing may be accomplished by centrifugation or other known washing techniques with washing media such as saline, RPMI and/or PAS V. Systems and methods that may be utilized to wash mononuclear cells in accordance with the present disclosure is described in U.S. patent application Ser. No. 13/733,607, filed on Jan. 3, 2013, entitled “Apparatus and Methods for Providing Treated and Washed Mononuclear Cells” which is incorporated herein by reference in its entirety. After the desired washing is complete, the washed mononuclear cell product may be returned or administered to a patient as needed as illustrated in step  52 . 
     The aforementioned apparatus and methods are effective for providing one or more therapeutic portions of cryopreserved ECP-treated mononuclear cells useful in the treatment of one or more diseases and/or side effects of existing therapies. Stated differently, and as demonstrated in the examples below, MNCs prepared in accordance with the apparatus and methods described herein retain their apototic trend: when compared to freshly ECP-treated MNC products that have not been cryopreserved and/or thawed, the encouraged apoptosis or apoptosis trend of the treated mononuclear cell product after cryopreservation and subsequent thawing is not significantly affected. The following non-limiting examples are provided. 
     Example A 
     Purpose: To investigate cryopreservation of ECP treated and untreated mononuclear cells and to compare apoptosis levels in cultures made from frozen/thawed cells with that of cultures made from freshly collected cells. 
     Methods: Mononuclear cells were collected from healthy male donors using the Amicus Separator (Fenwal, Inc.) with the following settings: 2000 mL cycle volume, 12:1 WB to ACD-A ratio, MNC offset of 1.5 or 2.3 and RBC offset of 6.0 or 6.8 (n=8). The MNC product was diluted 1:1 with saline and incubated with 200 ng/mL 8-MOP (Sigma) for 15 minutes in the dark. An aliquot of cells was removed prior to irradiation to serve as an untreated control. 
     300 mL of diluted MNC product was irradiated for 10 minutes in an EVA bag (surface area 500 cm 2 ) using the Therakos UVAR XTS device. Post irradiation, treated and untreated cells were purified using a Ficoll gradient. “Fresh” treated and untreated samples were resuspended for culture at 1-2×10 6 /mL in RPMI 1640 media supplemented with 2 mM glutamine and 10% human serum. “Cryo” treated and untreated samples were diluted 1:1 with freezing media (7% DMSO, 2% human serum in RPMI1640), aliquoted into cryovials and then cryopreserved with an uncontrolled rate freezer at −80° C. 
     After 1 week of cryopreservation, the cryovials were thawed rapidly in a 37° C. water bath and washed with 500 U/ml. DNase 1 and 1% human serum in PBS. The cells were washed twice with RPMI 1640 followed by culture at 1-2×10 6 /mL in RPMI 1640 media supplemented with 2 mM glutamine and 10% human serum. Fresh and cryopreserved/thawed cells were cultured at 37° C. in a humidified chamber with 5% CO 2  for up to 72 hours. After 0, 24, 48 and 72 hours, samples were assayed for lymphocyte apoptosis. Apoptosis was measured as the % of CD45+/Annexin-V positive cells in the lymphocyte forward/side scatter gate. 
     The results of the aforementioned apoptosis measurements are shown in  FIG. 5 , which graphically illustrates the % of apoptotic lymphocytes measured over 72 hours. It can be seen that the apoptosis trend of ECP treated cells that were cryopreserved and subsequently thawed was not significantly affected, as the percentage (%) of apoptotic lymphocytes is essentially the same as that for freshly ECP-treated cells over a 72 hour period. 
     Example B 
     The purpose and methods of Example B are essentially the same as Example A with the following exceptions: Example B was conducted on a larger scale than Example A such that cryo-bags were used in Example B in place of the cryo-vials used in Example A. Untreated and treated cells were frozen in Example B without Ficoll purification (n=4). Treated and untreated cells were diluted 1:1 with freezing media (7-10% DMSO, 2% human serum in RPMI1640) and frozen in EVA bags (70-80 mL total volume per 500-750 mL cryobag). Post-thaw, the cells were washed with or without DNAse I and re-suspended for culture at 1-2×10 6 /mL in RPMI 1640 media supplemented with 2 mM glutamine and 10% human serum. 
     As with Example A and as shown in  FIG. 6 , the apoptosis trend of ECP treated cells that were cryopreserved and subsequently thawed was not significantly affected. In other words, the percentage (%) of apoptotic lymphocytes of a mononuclear cell product after ECP treatment is within approximately 20% of the percentage of apoptotic cells of fresh (non-cryopreserved) ECP treated cells over a given period of time. 
     It will be understood that the embodiments described above are illustrative of some of the applications of the principles of the present subject matter. Numerous modifications may be made by those skilled in the art without departing from the spirit and scope of the claimed subject matter, including those combinations of features that are individually disclosed or claimed herein. For these reasons, the scope hereof is not limited to the above description.