CD23 Receptor Positivity Has No Prognostic Implication in Chronic Lymphocytic Leukemia.

Chronic Lymphocytic Leukemia (CLL) phenotypically expresses CD23, although the percentage of positive cells measured by flow cytometry is variable. We sought to analyze whether the percent of CD23 positive cells in the CLL clone correlates with time to treat (TTT), overall survival (OS) and prognostic markers CD38, ZAP-70, and IGHV mutation status.

We retrospectively analyzed the flow cytometry data of 332 CLL patients on the gated population of cells that were CD5 and CD19 positive. Percentage positivity for CD23, CD38, and ZAP-70 was noted. CD38 and ZAP-70 were considered positive at cut-offs of >= 30% and >=20%, respectively. CD23 was considered negative at <30% and positive at >= 30%. IGHV sequence was determined from cDNA and then compared to germline to assess mutation status using IMGT/V-QUEST.

The distributions of time from diagnosis until start of treatment and overall survival were stratified by CD23 positivity, estimated using the product limit method, and compared using the log rank test. Those who had expired without treatment or were alive and not treated at this time point were censored in the TTT analysis. Those who were still alive were censored in the OS analysis. Associations of CD23 positivity with IGHV mutation status, ZAP-70, and CD38 positivity were examined using the chi-square test.

Out of 332 patients, 25 had diminished CD23 expression (<30%) whereas 307 had normal CD23 expression (>30%). There was no difference in time until start of treatment or overall survival based on CD23 %positivity. CD23 %positivity showed no associations with IGHV mutation status, ZAP-70 or CD38 positivity.

CD23 percent positivity has no prognostic significance in CLL. There is no correlation between CD23 percent positivity and poor prognostic markers such as CD38, ZAP-70, or IGHV mutation status.

No relevant conflicts of interest to declare.