Clinical Significance of Plasma Levels of Soluble CD40 in Patients with Chronic Lymphocytic Leukemia

CD40 ligation provides signals central to chronic lymphocytic leukemia (CLL) cell survival and proliferation. The release of soluble CD40 (sCD40) may impact on both these signals and CD40 targeted therapies. In this study we investigated the prognostic significance of plasma sCD40 inuntreated CLL patients (n = 34). We report that 56% had levels higher than those of normal donors and that elevated levels were associated with significantly shorter treatment free (TFS) and overall survival. In bivariate analysis sCD40 remained a significant marker of TFS independent of Binet staging, CD38 positivity and lymphocyte count. RT-PCR analysis demonstrated that CLL cells expressed transcripts encoding putative sCD40. These results suggest sCD40 may play a role in CLL progression and that its function, prognostic significance and potential impact on antibody based therapies should be further investigated.