The Future of Biologic Agents in the Treatment of Sjögren 's Syndrome The gain in knowledge regarding the cellular mechanisms of T and B lymphocyte activity in the pathogenesis of Sjögren 's syndrome -LRB- SS -RRB- and the current availability of various biological agents -LRB- anti-TNF-α , IFN - α , anti-CD20 , and anti-CD22 -RRB- have resulted in new strategies for therapeutic intervention . In SS , various phase I and II studies have been performed to evaluate these new strategies . Currently , B cell-directed therapies seem to be more promising than T cell-related therapies . However , large , randomized , placebo-controlled clinical trials are needed to confirm the promising results of these early studies . When performing these trials , special attention has to be paid to prevent the occasional occurrence of the severe side effects . Introduction Sjögren 's syndrome -LRB- SS -RRB- is a chronic lymphoproliferative autoimmune disease with disturbances of T lymphocytes , B lymphocytes , and exocrine glandular cells -LSB- 1 -RSB- . SS can be primary -LRB- pSS -RRB- or secondary SS -LRB- sSS -RRB- , the latter being associated with another autoimmune disease -LSB- e.g. , rheumatoid arthritis , systemic lupus erythematosus -LRB- SLE -RRB- -RSB- . Lymphocytic infiltrates are a characteristic histopathological finding in SS . These infiltrates consist of T and B cells . The expression of different cytokines , such as tumor necrosis factor-α -LRB- TNF-α -RRB- and interferon-α -LRB- IFN-α -RRB- , during the formation and proliferation of these infiltrates has been investigated . There is an overexpression of TNF-α , which is secreted by CD4 + T lymphocytes , mononuclear cells , and epithelial cells -LSB- 2 -RSB- . The intraglandular synthesis of TNF-α causes destruction of acini by up-regulation of Fas at the surface of the glandular epithelial cells , stimulation of secretion of type 2 and 9 matrix metalloproteases by epithelial cells , and overexpression of different chemokines -LSB- 3 -- 5 -RSB- . IFN-α is produced by activated plasmacytoid dendritic cells in primary SS -LRB- pSS -RRB- , and numerous IFN-α-producing cells have been detected in labial salivary glands -LSB- 6 -RSB- . IFN-α promotes the autoimmune process by increasing autoantibody production and through the formation of endogenous IFN-á inducers . IFNs have potent immunomodulating properties and are thought to trigger a systemic biological response -LSB- 7 -RSB- . Besides the presence of proinflammatory cytokines , described in the previous paragraph , recent studies have shown an important role for B cells in the pathogenesis of SS . Presence of autoantibodies and hypergammaglobulinemia are both considered to reflect B cell hyperactivity . Systemic complications of SS are associated with this B cell hyperactivity -LSB- 8 -RSB- . Moreover , about 5 % of SS patients develop malignant B cell lymphoma -LSB- 9 -RSB- . B cell activating factor -LRB- BAFF -RRB- , also known as B lymphocyte stimulator -LRB- BLyS -RRB- , is an important factor in local and systemic autoimmunity -LSB- 1 -RSB- . Dysregulated BAFF expression is implicated in disease progression and perpetuation of humoral autoimmunity . Overproduction of BAFF in transgenic mice has been shown to result in B cell proliferation and antibody production resulting in inflammation and destruction of the salivary glands , as well as kidney failure similar to observations seen in SLE -LSB- 10 -RSB- . In humans , circulating BAFF levels are increased in patients with pSS and correlate with disease activity -LSB- 11 -RSB- . Recent insights in the cellular mechanisms of T and B lymphocyte activity in the pathogenesis of SS and the current availability of various biological agents have resulted in new strategies for therapeutic intervention . The use of these biological agents in the treatment of SS will be discussed in this review . Biological Agents Currently , biological agents have been introduced in various systemic autoimmune diseases , as rheumatoid arthritis and SLE . Biological agents most frequently applied in autoimmune diseases are monoclonal antibodies , soluble receptors , and molecular imitators -LSB- 12 -RSB- . These biological agents enhance or replace conventional immunosuppressive therapy . In contrast to rheumatoid arthritis and SLE , no biological agent has been approved yet for the treatment of SS , but several phase II and III studies have been or are currently conducted . The biological agents used in SS trials are IFN-α and agents targeting TNF-α and B cells -LRB- anti-CD20 , anti-CD22 -RRB- . Although no trials have been performed yet with BAFF antagonists , this might be a promising therapy -LSB- 13 -RSB- and will be discussed in this review , as well . Anti-TNF-α Monoclonal Antibodies There are three main biological agents targeting TNF-α : the chimeric monoclonal IgG1 antibody infliximab , the receptor fusion protein etanercept , and the fully humanized monoclonal antibody adalimumab . In an open-label study , short-term treatment with infliximab was reported to be very effective in active pSS over a 3-month period -LSB- 14 -RSB- . Sixteen patients received three infusions -LRB- 3 mg/kg -RRB- at weeks 0 , 2 , and 6 , which led to significant improvement in all clinical and functional parameters , including global assessments , erythrocyte sedimentation rate , whole salivary flow rate , tear secretion -LRB- Schirmer test -RRB- , tender joint count , fatigue score , and sensation of dry eyes and dry mouth . Three patients , all with short disease duration -LRB- < 3 years -RRB- , were considered to be in complete remission up till 1 year . In 10 out of the 16 patients , SS symptoms , particularly mouth dryness , relapsed after a median of 9 weeks . In a follow-up study , a maintenance regimen of one infusion every 12 weeks was evaluated in these 10 patients . Retreatment induced an improvement of signs related to SS that was comparable with the effects from the three loading infusions -LSB- 15 -RSB- . To confirm these promising results from an uncontrolled study , the Trial of Remicade In Primary Sjögren 's Syndrome study was designed . In this multicenter , double-blinded , placebo-controlled , randomized clinical trial , 103 patients with active pSS were included and treated with infliximab infusions -LRB- 5 mg/kg -RRB- or placebo at weeks 0 , 2 , and 6 . Follow-up was 22 weeks . Primary endpoint was an improvement of > 30 % of two of three VAS scores measuring joint pain , fatigue , and dry eyes . There were several secondary endpoints of which one was the basal salivary flow rate . In contrast to the previously mentioned uncontrolled studies , no evidence of efficacy of infliximab treatment on all clinical and functional parameters could be demonstrated in this randomized controlled clinical trial -LSB- 2 -RSB- . A trial on 15 pSS patients -LRB- mean disease duration 3.6 years -RRB- with 25-mg etanercept , subcutaneously twice a week for 12 weeks , did not reveal a reduction in sicca symptoms and signs , neither did the repeated treatment for up to 26 weeks . Only in the subset of four patients with severe fatigue a decrease in fatigue was observed -LSB- 16 -RSB- . Another trial evaluating subcutaneous administration of etanercept vs placebo for 12 weeks -LRB- 28 patients -RRB- also showed no clinical efficacy -LSB- 17 -RSB- . No trials of adalimumab treatment in pSS have been reported in the literature yet . In conclusion , TNF-targeting treatment could not be proven to be of benefit in reducing the complaints of pSS patients . IFN-α IFNs are proteins with antiviral activity and potent immunomodulating properties . SS patients have an activated type I IFN system -LSB- 6 -RSB- . Such a role for IFN-α appears to contradict the reports described below , that low doses of IFN-α administered via the oromucosal route increase the unstimulated salivary output . However , it is hypothesized that oral IFN-α treatment may act by increasing saliva secretion by up-regulation of aquaporin 5 transcription without significantly influencing the underlying autoimmune process -LSB- 6 , 7 -RSB- . In a phase II study , treatment of pSS patients with IFN-α administered via the oromucosal route -LRB- by dissolving lozenges -RRB- was demonstrated to be effective -LRB- improvement of salivary output , decreased complaints of xerostomia -RRB- and safe -LSB- 18 -RSB- . Based on these promising results , a randomized , parallel group , double-blinded , placebo-controlled clinical trial -LRB- 497 pSS patients -RRB- was designed . Patients were randomized into two groups and received a 24-week daily treatment with either 450 IU IFN-α -LRB- 150 IU three times per day -RRB- or placebo in a ratio 3:2 , administered by the oromucosal route . This randomized , controlled clinical trial failed to demonstrate a significant effect on the primary endpoints -LRB- VAS score for oral dryness and stimulated whole salivary flow -RRB- in the IFN-α group relative to the placebo group . There was a significant increase in unstimulated whole saliva in the patients treated with IFN-α , which correlated positively and significantly with improvement in seven of eight symptoms associated with oral and ocular dryness . No adverse events were observed -LSB- 7 -RSB- . In conclusion , no clinical evidence for the efficacy of IFN-á treatment in pSS patients has been shown yet ; however , an improvement of unstimulated whole saliva was observed . Further research is needed to objectify the effect of IFN-á on salivary gland tissue . Anti-CD20 Monoclonal Antibodies Anti-CD20 -LRB- rituximab -RRB- is a chimeric humanized monoclonal antibody specific for the B cell surface molecule CD20 , which is expressed on the surface of normal and malignant pre-B and mature B lymphocytes . CD20 mediates B cell proliferation and differentiation . This antibody has been demonstrated to prevent B cells from proliferating and to induce lysis of B cells by complement-dependent and antibody-dependent cytotoxicity mechanisms as well as by direct induction of apoptosis -LSB- 19 -RSB- . Rituximab is currently used for the treatment of low-grade B cell lymphomas -LSB- 20 -RSB- . In controlled studies , it was shown to be safe and effective in the treatment of rheumatoid arthritis -LSB- 21 -- 23 -RSB- . Moreover , open-label studies in SLE patients are promising -LSB- 24 -RSB- . In an open-label phase II study , 15 patients with pSS were treated with 4 infusions of rituximab -LRB- 375 mg/m2 once weekly -RRB- and followed up for a 3-month period . Eight of the 15 patients were early pSS patients -LRB- mean disease duration 28 months , all had residual salivary gland function at baseline -RRB- , and 7 patients had a concomitant mucosa-associated lymphoid tissue -LRB- MALT -RRB- lymphoma -LRB- mean disease duration 79 months -RRB- . In the early pSS patients , rituximab treatment resulted in significant improvement of subjective symptoms and an increase in salivary gland function . All patients showed a rapid depletion of peripheral B cells within a few weeks , accompanied by a decrease in IgM-RF levels -LSB- 8 -RSB- . Repeated parotid gland biopsies in five of the early patients after treatment showed redifferentation of the lymphoepithelial duct lesions into normal striated ducts , possibly indicating regeneration of salivary gland tissue -LRB- unpublished data -RRB- . Five of the eight pSS patients without a MALT lymphoma received a second course of rituximab -LRB- after 9 -- 11 months -RRB- due to recurrence of symptoms . Retreatment resulted in the same significant improvement of the salivary flow rate and subjective symptoms compared to the results of the first treatment , together with a decrease in B cells and IgM-RF levels . Six of the seven MALT/pSS patients were initially effectively treated with rituximab . The remaining MALT/pSS patient had progressive MALT disease and severe extraglandular SS disease within 3 months after the start of rituximab treatment . Cyclophosphamide was added , which led to stable disease of both MALT and SS . One of the six patients initially responding had a recurrence of MALT lymphoma after 9 months and was successfully retreated with rituximab . The other patients are still in remission -LRB- unpublished data -RRB- . In another open-label study , 16 pSS patients received only two weekly rituximab infusions -LRB- 375 mg/m2 -RRB- , with a follow-up of 36 weeks . Again , treatment resulted in rapid complete depletion of peripheral B cells . At week 12 , a significant improvement of VAS scores for fatigue and dryness was recorded , and at week 36 , a significant improvement for VAS scores for global disease , fatigue , dry mouth , dry eyes , and dry vagina , but also in the number of tender joint and tender joint counts was seen -LSB- 25 -RSB- . Both in the study of Pijpe et al. -LSB- 8 -RSB- and the study of Devauchelle-Pensec et al. -LSB- 25 -RSB- , patients with a short disease duration showed more improvements than patients with longer disease duration . Two trials retrospectively evaluated the effect of rituximab -LRB- four infusions of 375 mg/m2 -RRB- in 18 pSS patients -LRB- mean disease duration 10 years -RRB- with systemic features . Self-reported dryness improved in six patients -LRB- VAS scores not known for three patients , no improvement in the other nine patients -RRB- . Both studies reported good efficacy of the treatment on systemic features -LSB- 26 , 27 -RSB- . In conclusion , in phase II trials , it has been shown that rituximab seems to be effective for at least 6 -- 9 months in pSS patients with active disease , improving both subjective and objective complaints . Retreatment with rituximab resulted in a similar good clinical response . In pSS patients with longer disease duration , without residual salivary gland function , rituximab treatment seems to be effective for systemic features . To confirm these promising results , randomized placebo-controlled clinical trials are needed . Anti-CD22 Monoclonal Antibodies Epratuzumab is a fully humanized monoclonal antibody specific for the B cell surface molecule CD22 . CD22 is expressed on the surface of normal mature and malignant B lymphocytes . CD22 appears to be involved in the regulation of B cell activation through B cell receptor signaling and cell adhesion -LSB- 28 -RSB- . In an open-label phase I/II study , safety and efficacy of epratuzumab were investigated in 16 pSS patients . Follow-up was 6 months . These pSS patients received four doses of 360 mg/m2 epratuzumab intravenously . Mean disease duration before therapy was 2.9 years , and none of the patients had received prior B cell-targeted therapy . Most improvements occurred in the Schirmer test , unstimulated whole salivary flow and the VAS score for fatigue . The new developed disease activity score consisted of the four domains : dryness of the eyes , dryness of the mouth , fatigue , and laboratory parameters . Based on this score , 53 % achieved at least 20 % improvement in at least two domains at 6 weeks . Corresponding rates for 10 , 18 , and 32 weeks are 53 , 47 , and 67 % . Remarkably , the number of responders was higher 6 months after the treatment administration than earlier . Peripheral B cells decreased with a median decrease of 54 and 39 % at 6 and 18 weeks , respectively . In conclusion , epratuzumab seems to be an effective treatment . Randomized , placebo-controlled clinical trials are needed before epratuzumab can be advised for general treatment in pSS patients -LSB- 29 -RSB- . Anti-BAFF BAFF is a B cell-activating factor that acts as a positive regulator of B cell function and expansion . BAFF levels were found elevated in serum and saliva in SS patients , but no correlation could be shown between serum and saliva levels -LSB- 30 -RSB- . However , circulating levels of BAFF in pSS patients were shown to be a marker for disease activity -LSB- 11 -RSB- . To the best of our knowledge , no trials have been performed with anti-BAFF treatment in SS yet , but such an approach might be considered for future trials . Currently , two human BAFF antagonists have been developed , a human antibody -LRB- anti-BLyS -RRB- that binds to soluble BAFF and a fusion protein of one of the BAFF receptors -LSB- 31 , 32 -RSB- . Especially , SS patients with elevated BAFF levels , hypergammaglobulinemia , elevated levels of autoantibodies , and associated B cell lymphoma might be candidates for anti-BAFF treatment -LSB- 33 -RSB- . Safety and Tolerability of Biological Agents The most important side effects of treatment with biological agents are direct mild infusion reactions . Several patients developed a serum sickness-like disease a few days after the second infusion that might be related to the formation of antibodies against the biological agent -LSB- human anti-chimeric antibodies -LRB- HACAs -RRB- or human anti-human antibodies -RSB- . A few patients developed infections during treatment with a biological agent ; however , some patients concomitantly used other immunosuppressive therapies . Therefore , the direct relation between the biological agent and the infection is unsure . All adverse events reported in the trials described in this review are reported in Table 1 . According to this table , the most frequent side effects of treatment with biological agents are mild infusion reactions . The most severe side effect of the various treatments used in SS patients was the development of a serum sickness-like disease . This adverse effect of treatment occurred in 16 % -LRB- 8 of 49 -RRB- of the patients treated with rituximab . HACA formation was observed in patients developing a serum sickness-like disease and occurred only in patients receiving low-dose corticosteroids and no other immunosuppressive drugs . It is assumed that higher doses of corticosteroids during treatment might prevent the occurrence of serum sickness . Table 1Adverse events after treatment with biological agents in SS Agent/doseNumber of patients in trial -LRB- number treated with the agent -RRB- Premedication/concomitant immunosuppressive therapyInfusion reactionInfectionsSerum sicknessHACA/HAHA formationOtherAnti-TNF-α monoclonal antibodiesSteinfeld -LSB- 14 -RSB- Infliximab intravenous , 3 mg/kg16 -LRB- 16 -RRB- n.r. / no1 -LRB- 6 % -RRB- 2 -LRB- 13 % -RRB- -LRB- respiratory tract -RRB- -- n.r. -- Steinfeld -LSB- 15 -RSB- Infliximab intravenous , 3 mg/kg10 -LRB- 10 -RRB- n.r. / no4 -LRB- 40 % -RRB- 2 -LRB- 20 % -RRB- -LRB- enteritis , tonsillitis -RRB- -- n.r. -- Marriette -LSB- 2 -RSB- Infliximab intravenous , 5 mg/kg103 -LRB- 54 -RRB- n.r. / continuation of hydroxychloroquine and corticosteroids -LRB- ≤ 15 mg/day -RRB- 2 -LRB- 4 % -RRB- 2 -LRB- 4 % -RRB- -LRB- 1 cutaneous , 1 respiratory tract -RRB- -- n.r. 2 -LRB- breast cancer , auto-immune hepatitis -RRB- aZandbelt -LSB- 16 -RSB- Etanercept subcutaneously , 25 mg15 -LRB- 15 -RRB- n.r. / pilocarpine at a constant dose -- 1 -LRB- 7 % -RRB- -LRB- parotitis -RRB- -- n.r. -- Sankar -LSB- 17 -RSB- Etanercept subcutaneously , 25 mg28 -LRB- 14 -RRB- n.r. / allowed to use long-term medication1 -LRB- 7 % -RRB- 1 -LRB- 7 % -RRB- -LRB- skin lesion -RRB- b -- n.r. -- IFN-αShip -LSB- 18 -RSB- IFN-α oromucosal , 150 IU , 450 IU109 -LRB- 87 -RRB- n.r. / non.a . -- -- n.r. -- cCummins -LSB- 7 -RSB- IFN-α oromucosal , 450 IU497 -LRB- 300 -RRB- n.r. / non.a . -- -- -- 23 -LRB- 7.7 % -RRB- d -LRB- 34 % gastrointestinal , 25 % musculoskeletal -RRB- Anti-CD20Pijpe -LSB- 8 -RSB- Rituximab intravenous , 375 mg/m215 -LRB- 15 -RRB- 25 mg prednisolon intravenously/patients with severe extraglandular manifestations -LRB- n = 3 -RRB- received immunosuppressive therapy2 -LRB- 13 % -RRB- 1 -LRB- 7 % -RRB- -LRB- zoster -RRB- 4 -LRB- 27 % -RRB- e4 -LRB- 27 % -RRB- -- Devauchelle-Pensec -LSB- 25 -RSB- Rituximab intravenous , 375 mg/m216 -LRB- 16 -RRB- n.r. / no -- -- 1 -LRB- 6 % -RRB- n.r. -- Gottenberg -LSB- 26 -RSB- Rituximab intravenous , 375 mg/m26 -LRB- 6 -RRB- n.r. / hydroxychloroquine -LRB- n = 1 -RRB- , methylprednisolone -LRB- n = 3 -RRB- 1 -LRB- 17 % -RRB- -- 1 -LRB- 17 % -RRB- n.r. -- Seror -LSB- 27 -RSB- Rituximab intravenous , 375 mg/m212 -LRB- 12 -RRB- n.r. / cyclophosphamide -LRB- n = 1 -RRB- , hydroxychloroquine -LRB- n = 1 -RRB- , leflunomide -LRB- n = 1 -RRB- 1 -LRB- 8 % -RRB- -- 2 -LRB- 17 % -RRB- n.r. -- Anti-CD22Steinfeld -LSB- 29 -RSB- Epratuzumab intravenous , 360 mg/m216 -LRB- 16 -RRB- 0.5 -- 1 g acetominophen , 25 -- 50 mg antihistamine . / no2 -LRB- 13 % -RRB- 2 -LRB- 13 % -RRB- -LRB- sinusitis , dental abscess -RRB- -- 3 -LRB- 19 % -RRB- 6 -LRB- 38 % -RRB- -LRB- TIA , osteoporotic fracture , diarrhea , dyspepsia , palpitations , paresthesia -RRB- n.a. Not applicable , n.r. not reported , HACA human anti-chimeric antibodies , HAHA human anti-human antibodiesaOne patient in the placebo group developed benign lymph node enlargementbOne patient in the placebo group developed a prolonged upper respiratory tract infectioncIn this study , there were mild adverse events ; however , there were no significant differences between the groups . Adverse events were not specified.dEight patients -LRB- 4.1 % -RRB- in the placebo group developed adverse eventseOne of these 4 patients developed serum sickness after retreatment -LSB- 8 -RSB- Future Perspectives Biological agents are promising therapies for SS . Randomized studies failed to show a clinical effect of anti-TNF-α and IFN-α in the treatment of SS . Notwithstanding the unfortunate results of anti-TNF-α and IFN-α , B cell depletion -LRB- both anti-CD20 and anti-CD22 -RRB- seems very promising . Again , this promising effect , as was previously also assumed for anti-TNF-α and IFN-α , must be confirmed in larger randomized controlled clinical trials . HACAs have been reported to occur at a higher rate in patients with an autoimmune disease . It seems that monoclonal antibodies are more immunogenic in active autoimmune disease , independent of the type of disease . Additional use of immunosuppressive therapy in these patients might be mandatory to prevent serious side effects . These unwanted side effects might also be prevented by the use of fully humanized antibodies . The currently available humanized antibodies are promising , but need further study . Moreover , there is still a need for improved assessment parameters to monitor treatment effects , both subjectively and objectively . For studies on intervention of SS , evaluation of the parotid gland might be of use because function , composition of saliva , and histology can be evaluated on the same gland at different time points . Activity scores are currently under development by Bowman and Vitali -LSB- 34 , 35 -RSB- . Finally , as soon as effective intervention treatments have been established , the cost-effectiveness of these currently very expensive antibodies needs to be analyzed to select those patients that might benefit the most from this kind of treatment .

O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O B O O B I O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O B I O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O

biological agent
treatment
monoclonal antibody
therapy
autoimmune disease