Serum Levels of Soluble CD23, but not Soluble CD25, Predict Disease Progression in Early Stage B-Cell Chronic Lymphocytic Leukemia

Serum levels of the soluble forms of CD23 (sCD23) and CD25 (sCD25) were prospectively analyzed with respect to their prognostic relevance in early stage B-cell chronic lymphocytic leukemia (B-CLL). SCD23 and sCD25 levels were determined in 105 patients with newly diagnosed B-CLL (Binet stage A). In 93 of the patients, these levels were correlated with other already established indicators for risk of disease progression, including the histologic pattern of bone marrow infiltration, lymphocyte doubling time (LDT), and the serum level of thymidine kinase (TK). High serum levels of both sCD23 and of sCD25 were associated with a diffuse bone marrow infiltration, a LDT ≤12 months, and elevated (>5 U/L) serum TK, respectively. Moreover, examination of the clinical course of 76 untreated patients showed that high levels of sCD23, but not of sCD25, at initial diagnosis were linked with disease progression. Furthermore, in a stepwise Cox regression model, high levels of sCD23 and a short LDT were shown to be strong predictors of progressive disease within the first year of disease presentation. Therefore, it appears to be justified to incorporate sCD23 levels into the risk profile of early stage B-CLL and to take them into account for stratification in risk-adapted treatment strategies.