Clinical Significance of CD11c Expression Levels in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma

CD11c is an adhesion molecule that is expressed by different B-cell lymphomas including chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). CLL/SLL is primarily a peripheral blood (PB) and bone marrow (BM) disease, however, a subset of patients may present with lymphadenopathy (LAP) and/or splenomegaly. Here we study the relation between CD11c expression in CLL/SLL with the clinical presentation and outcome of the disease. Retrospectively, 64 cases of CLL/SLL were identified in the archive of authors' institution between 2002 and 2003. However, only 16 (25%) were qualified for the 10-year follow-up with documented expression levels of CD11c. The expression level was evaluated by flow cytometry and was considered low, intermediate and high when <20%, 20%-50%, and >50% of the neoplastic cells express the antigen, respectively. There were 10 men and 6 women with a mean age of 73 years (range, 54–103 years). The initial presentation of CLL/SLL in all patients was in PB with mean lymphocyte count of 30 × 109/L (range, 7 - 95 × 109/L). The expression level of CD11c was low in 6.2% (n = 1), intermediate in 56.3% (n = 9) and high in 37.5% (n = 6). 12 patients presented with mild LAP (n = 3), extensive LAP (n = 6), or splenomegaly (n = 3). 50% (n = 8) showed BM involvement at the time of diagnosis and the expression level of CD11c in this group was as follows: 12.5% low, 50% intermediate, and 37.5% high. At 10-year of follow-up, 5 patients were alive and 11 patients were dead. In conclusion, the neoplastic cells in CLL/SLL frequently express CD11c at intermediate or high levels and such levels may be associated with lymphadenopathy and/or splenomegaly. However, there is no relation between the expression levels and disease outcome.