Association of CD38 antigen expression with other prognostic parameters in early stages of chronic lymphocytic leukemia.
The expression of the surface molecule CD38 on B cell chronic lymphocytic leukemia (B-CLL) cells has recently been described as a prognostic marker for patient survival. We have analyzed CD19/CD38 expression in 81 patients with predominantly early stages of B-CLL (69 Binet A, seven Binet B, five Binet C). Sixty-two patients (77%) had less than 30% CD38+/CD19+ cells, while 19 (23%) had > or = 30%. There was a significant association between Binet stages (A vs. B+C, p < 0.0001), Rai stages (0-II vs. III+IV, p < 0.001) and CD38 expression, confirming the published cut-off level of 30%. A particularly strong association between CD38 expression was found with soluble CD23 (sCD23) levels of > or = 2000 U/ml (p < 0.0001) and beta2-microglobulin (beta2 MG) serum levels of > or = 3 mg/l (p < 0.0001) indicating that CD38 is a marker of tumor mass as well as disease progression. A borderline association was found with lymphocyte doubling time (LDT) < 12 months (p = 0.05) due to low patient numbers, while there was no association with age, sex or immunoglobulin deficiency. Discordant results were obtained in a number of patients: 10 of 69 patients (14%) with Binet A had a CD38 > or = 30% while three of seven patients with Binet B had a CD38 < 30%. In these two subgroups CD38 and other prognostic factors gave discrepant results. Due to the early stage and short median observation time (12 months. range 1-24 months), calculations concerning patient survival were not performed. However, our data show a strong association between CD38 and other known prognostic factors. The results also suggest that this factor is not always reliable in Binet A patients.