Potential role of serum level of soluble CD44 and IFN-γ in B-cell chronic lymphocytic leukemia

Evidence indicates that the slowly expanding population of B cells that characterizes chronic lymphocytic leukemia (CLL) results primarily from defects in responses to cytokines. We evaluated the prognostic value of soluble CD44 and IFN-gamma in B-cell chronic lymphocytic leukemia (B-CLL) and analyzed their source and regulation secretion in B-CLL clones in vitro. Levels of soluble CD44 standard (sCD44s) and IFN-gamma were analyzed by enzyme-linked immunosorbent assay. B-CLL cells were separated and stimulated in vitro for the detection of both markers. Serum levels of sCD44s and IFN-gamma were significantly elevated in patients with B-CLL in comparison with normal persons. Elevated levels of sCD44s and IFN-gamma were associated with an advanced disease as reflected by increased values as stage progress. In B-CLL, sCD44s as well as IFN-gamma was shed from leukemia cells as shown by in vitro cultures. Stimulation of B-CLL clones results in a proliferation-associated increased secretion of sCD44s and IFN-gamma. B-CLL clones from advanced-stage patients are characterized by an increased capacity for proliferation and production of both markers in comparison with early-stage patients. Our present results suggest that sCD44 and IFN-gamma may be of major importance in the pathogenesis of B-CLL, and inhibition of the effects of sCD44 and IFN-gamma could be a potential therapeutic strategy.