Prognostic value of immunohistochemical expression of ZAP-70 and CD38 in chronic lymphocytic leukaemia detected on bone marrow and lymph node biopsies / Valoarea prognostică a expresiei imunohistochimice a ZAP-70 si CD38 în leucemia limfocitară cronică detectată pe biopsii osteomedulare și limfoganglionare

Chronic lymphocytic leukemia (CLL) has a heterogeneous clinical course. Among useful markers in identifiyng patients with poor outcome are unmutated IgVH, ZAP-70 and CD38 expression. Both ZAP-70 and CD38 were shown to be capable of identifying aggressive CLL.

We analysed data from 35 patients diagnosed with CLL based on morphological and immunophenotypical criteria. In all cases peripheral blood immunophenotyping was performed as initial diagnostic test. Immunohistochemical expression of ZAP-70 and CD38 was evaluated on 21 cases of lymph node biopsies and 14 cases of bone marrow biopsies, performed at the time of diagnosis. In addition in-situ hybridization for EBER-1 was evaluated.

The median age of patients was 60 years and we noted a slight male predominance. The immunophenotypic criteria (C23⁺, CD5⁺, CD20⁺, CD10^-, CD3^-, cyclinD1^-) for B-cell CLL were achieved in all 35 patients. We found that CLL cases showing expression of both markers (ZAP-70⁺CD38⁺ patients) are characterised by an unfavourable clinical course as compared with cases that did not show expression of markers (ZAP-70-CD38- patients). Our data showed significant differences in terms of overall survival at 5 years between the two groups. We also found statistically significant differences between patients ZAP-70^-CD38^- and patients with one or both positive markers (ZAP-70⁺ and/or CD38⁺).

Prognostic information given by ZAP-70 and CD38 could be used in guiding treatment decisions and they probably should be recommended to all patients with B-CLL in trying to obtain a more clear profile of the disease at the time of diagnosis.