CD38 expression as an important prognostic factor in B-cell chronic lymphocytic leukemia

CD38 is a transmembrane glycoprotein expressed on the surface of leukemic cells in a significant percentage of patients with B-cell chronic lymphocytic leukemia (B-CLL). A recent study suggested that CD38 expression has prognostic value in CLL. Peripheral blood samples from 218 patients with B-CLL were analyzed by flow cytometry for CD38 expression on CD5/19⁺ leukemic cells. Various patient characteristics were studied including age, sex, Rai and Binet stages, splenomegaly, hepatomegaly, hemoglobin (Hgb) level, β-2 microglobulin (β2M) level in the serum, number of nodal sites involved with disease, and length of survival. The Kaplan-Meier method was used to construct survival curves, and the log-rank statistic was used to compare these curves. CD38 was expressed in 20% or more of leukemic cells in 43% of the patients. Patients with high CD38 expression (20% or more) had significantly shorter survival times (P = .00005). Multivariate analyses showed that CD38 expression is an important prognostic factor associated with high incidence of lymph node involvement (P = .004), lower hemoglobin level (P = .001), hepatomegaly (P = .05), and high β2M level (P = .00005). CD38 expression identified a group of patients with aggressive disease that was considered by Rai staging to be early-stage disease (Rai stages 0-11). Patients with CD38⁺ samples have significantly aggressive disease regardless of their clinical stage. Measurement of CD38 expression by flow cytometry should become a routine test in the evaluation of patients with CLL.