psoriasis is a chronic immunologically - based inflammatory skin disease which affects approximately 2% of the general population [ 1 , 2 ] .
the presence of an unknown antigen causes the generation of effector t cells that infiltrate the skin and initiate a pathogenetic process by producing different types of cytokines .
tumor necrosis factor- ( tnf- ) is considered the most important cytokine involved in the pathogenesis of psoriasis [ 3 , 4 ] .
indeed , tnf- plays an important physiological role in host defense , inflammation and cell differentiation , and a pathological role in many conditions such as fever , rheumatoid arthritis and some malignant neoplasms , e.g. b - chronic lymphocytic leukemia ( b - cll ) .
b - cll is the most common form of leukemia in the western world , characterized by the slow and progressive accumulation of monoclonal cd5 + b lymphocytes in peripheral blood , bone marrow , lymph nodes and other organs .
b - cll is the first example of an indolent cancer characterized by abnormally low apoptosis rather than increased mitosis . although multiple apoptosis inhibiting factors other than tnf- have been identified in b - cll , several data indicate that tnf- is a central mediator in apoptosis resistance of malignant lymphocytes in b - cll .
a 41-year - old white woman , suffering from plaque psoriasis since she was 23 years old , was referred to our outpatient clinic .
she was not affected by psoriatic arthropathy and was known to be in good health with no other illnesses , no history of major surgical procedures and was receiving no concomitant medications .
she was administered two 8-month cycles of cyclosporine treatment with moderate results in 2005 and 2006 . in 2007 , she started phototherapy with ultraviolet b narrowband ; she did not experience good results because of a scarce compliance to this kind of treatment . in order to start a new therapy based on biologic drugs , all routine laboratory tests ( serum chemistry , hematology , and urinalysis ) were performed .
the results were normal except for a moderate lymphocytosis ( 63% , normal range 2045% ; 6.32  10/l , normal range 1.23.5  10/l ) with a normal white blood cell count .
afterwards , laboratory tests were repeated and moderate lymphocytosis was present again ; according to this evidence , a hematologic counseling was required , and the diagnosis of b - cll was made . since tnf- is reported as a common link between psoriasis and b - cll , two cycles of etanercept were administered ( 1 cycle = 12 weeks ) from january to june 2008 .
lymphocyte levels remained stable ( 61% ; 6.1  10/l ) , indicating no progression of the leukemia , but after 24 weeks of treatment , the patient did not achieve psoriasis area and severity index ( pasi ) 50 ( a 50% reduction in pasi score ) .
therefore , in december 2008 , she was started on a course of treatment with infliximab ( 5 mg / kg intravenous ) .
after the 3rd infusion of infliximab , a significant improvement of clinical manifestations was observed ( fig .
pasi and body surface area decreased from 12.4 to 5.5 and from 18.8 to 9.0% , respectively .
after 18 months of infliximab treatment , lymphocyte levels remained stable and psoriatic manifestations were under control .
here , we have described the case of a patient suffering from plaque psoriasis and b - cll .
the patient had suffered from psoriasis for 18 years and , like many other subjects with moderate - to - severe psoriasis , had received a series of different treatments ( topical and systemic ) in an attempt to control symptoms .
laboratory tests showed a moderate lymphocytosis so that a hematologic counseling was required and a diagnosis of b - cll was made .
a t - helper 1 cytokine - mediated pathway is involved in these disorders in which tnf- plays a central role .
tnf- involvement in psoriasis has been well validated by the clinical success of anti - tnf- therapy . on the other hand ,
tnf- is constitutively produced by b - cll cells , and it may act as an autocrine factor for their growth and survival . moreover , in b - cll patients , tnf- serum levels and soluble tnf- receptor ( stnfr ) levels are increased , and a correlation with disease progression has been demonstrated , associated with an adverse prognosis ; it has been hypothesized that high levels of tnf- and stnfr can predict outcome in lymphoma patients .
confirmed the relationship between tnf- plasma levels and the severity of b - cll , suggesting that they should be monitored together with other disease markers .
the first drug chosen was etanercept , a dimeric fusion protein consisting of the extracellular ligand - binding portions of two soluble tnf- receptors fused to a fc fragment of an immunoglobulin g1 molecule .
two cycles of etanercept were administered ( 50 mg twice a week for 12 weeks followed by 50 mg every week until 24 weeks ) with poor effects on psoriatic disease and no b - cll progression .
therefore , the patient was started on a course of treatment with infliximab ( 5 mg / kg intravenous ) .
infliximab is a chimeric murine / human immunoglobulin g1 monoclonal antibody that binds specifically to human tnf-. in our case , psoriatic lesions improved and b - cll showed a lack of progression during infliximab therapy . during 3 years of anti - tnf- therapy , the patient did not show significant modifications of lymphocyte levels .
on the basis of this evidence , tnf- could represent a therapeutic target in patients affected by both psoriasis and b - cll ; specific inhibition of tnf- , either with dimeric fusion protein etanercept or the monoclonal antibody infliximab , could potentially result in the control of proliferation of the leukemic clone .
we report this case to highlight the possibility to administer anti tnf- treatment in psoriatic patients affected by concomitant b - cll .
 psoriasis is a chronic immunologically - based inflammatory skin disease . 
 b - chronic lymphocytic leukemia ( b - cll ) is a form of leukemia characterized by the slow and progressive accumulation of monoclonal cd5 + b lymphocytes in peripheral blood , bone marrow , lymph nodes and other organs . a t - helper 1 cytokine - mediated pathway is involved in these disorders in which tumor necrosis factor- ( tnf- ) plays a central role . 
 tnf- is involved in physiological phenomena , such as host defense , inflammation and cell differentiation , and in many pathological conditions , such as fever and some malignant neoplasms . 
 tnf- involvement in psoriasis has been well validated by the clinical success of anti - tnf- therapy . 
 tnf- has been well studied in the pathogenesis of b - cll , suggesting it as a target in b - cll therapy . 
 we present the case of a patient suffering from plaque psoriasis and b - cll . 
 since tnf- is reported as a common link between psoriasis and b - cll , the patient was treated with etanercept followed by infliximab , two anti - tnf- drugs . during 3 years of therapy 
 , the patient did not show significant modifications of lymphocyte levels , indicating no progression of b - cll . 
 we report this case to highlight the possibility to administer anti - tnf- treatment in psoriatic patients affected by concomitant b - cll . 