The Expression And Clinical Significance Of ZAP-70 And CD38 In B-CLL Chronic Lymphocytic Leukemia

Objective: B-CLL chronic lymphocytic leukemia(B-CLL) is a heterogeneousdisease characterized by a variable clinical course. Several prognosticmarkers have been identified to predict clinical course in recent years,immunoglobulin variable heavy chain (IgV_H) mutation status is considered asthe most powerful factor among the markers. However, IgVH mutationanalysis is based on DNA sequencing, which is technically difficult,expensive, time-consuming and not available for routine clinical use. Therecent studies suggest ZAP-70 and CD38 expression have close correlationwith IgV_H mutation status and they can surrogate (IgV_H) mutation status asprognostic markers to predict clinical course of B-CLL. ZAP-70 and CD38expression are determined by flow cytometry in our study, clinical dataincluding other prognostic markers were also collected, We aimed to analyzethe correlation between ZAP-70 and CD38 expression and other markers andto evaluate the prognostic role of ZAP-70 and CD38 so as to provide reliableinformation for individualized therapy and early intervention of clinical trial. Methods: Peripheral B-CLL cells of 50 patients were analyzed for ZAP-70and CD38 expression by four-color flow cytometry .Patients were consideredpositive when the expression were more than 20% cutoff for ZAP-70 and30% cutoff for CD38 .The CDS+ T cells in the same sample were used asinternal positive control, Isotype control was use for every sample .serumβ2-microglobulin was analyzed by ratenephelometry.Results:1. patients (50%) were ZAP-70 positive and 25 patients (50%) were ZAP-70negative. 64% and 55% B-CLL patients progressed from A to B+C inZAP-70~+ and ZAP-70~- group respectively at analysis.2. patients (28%) were CD38 positive and 36 patients (72%) were CD38negative. 75% and 55% B-CLL patients progressed from A to B+C inCD38~+ and CD38~- group respectively at analysis.3. of 50(22%) patients were concordant ZAP-70~+CD38~+ and 22 of 50(44%)patients were concordant ZAP-70~-CD38~-. As a result, 33 patients (66%)were concordant and 17 patients (34%) were discordant in ZAP-70 andCD38 expression. 100%,44% and 58% B-CLL patients progressed fromA to B+C in double positive, discordant and double negative grouprespectively at analysis4. No significant difference for disease stages, total white bloodcell,lymphocyte, hemoglobin, platelet count of blood routine test andserumβ2-microglobulin were observed in either of or combinedZAP-70 and CD38 expression at analysis (P＞0.05).5. The median time to progress for ZAP-70+ and ZAP-70-patients were24 months and 48 months respectively, significant difference was observed between the two groups(P=0.001); The median time to progressfor CD38+ and CD38-patients were 13 months and 31 monthsrespectively, no significant difference was observed between the twogroups (P=0.506),There were still no significant difference when 7% or20% cutoff for CD38 were used; The median time to progress forZAP-70~+/CD38~+, ZAP-70~+/CD38~- or ZAP-70~-/CD38~+ andZAP-70~-/CD38~- patients were 14 months ,24 and 56 monthsrespectively, significant difference were observed among the threesubgroups , but no difference was found between ZAP-70~+/CD38~- orZAP-70~-/CD38~+ and ZAP-70~-/CD38~-patients when any two of threesubgroups were compared. The correlation between expression ofZAP-70 and CD38 and survival time can not be evaluated because onlyone of 50 patients had died at the time of analysis.6. No correlation was observed between ZAP-70 and CD38 expression.Conclusion:1. ZAP-70 and CD38 expression in B-CLL have no correlation with clinicalstages, total white blood cells, lymphocytes, hemoglobin, platelet countof blood routine test, and serumβ2-microglobulin at analysis.2. ZAP-70 has independent prognostic value for the time to progress ofB-CLL, while CD38 has no prognostic value for the time to progress ofB-CLL. Combined ZAP-70 and CD38 can not improve the prognosticvalue of either of the two factors.3. No correlation was observed between ZAP-70 and CD38 expression.Thecorrelation between ZAP-70 and CD38 expression and survival time willbe followed up. 4. Considering the convenience, quickness, low cost and availability in mostlaboratories, ZAP-70 expression determined by flow cytometry should beavailable for routine test so as to provide more prognostic information forindividualized therapy. CD38 expression should be also analysedsimultaneously to investigate the stability and correlation with survivaltime though CD38 has no prognostic value for the time to progress.