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Chronic Lymphocytic leukemia (CLL) is sometimes associated with autoimmune cytopenia: autoimmune hemolytic anemia (5-25% of cases) and immune thrombocytopenia (1-8% of cases)]. The effect of immune thrombocytopenia (ITP) on the clinical outcome and survival of patients with CLL is controversial.

The aim of the study was to correlate of ITP-CLL evidence with biological features, phenotypic and cytogenetic abnormalities and disease outcome in patients with B-CLL.

We studied 175 patients with B-cell CLL. All patients were diagnosed according to the revised criteria of the National Cancer Institute-sponsored Working Group (NCI-WG) on Chronic Lymphocytic Leukemia (CLL) and were classified according to the Rai staging system. Twelve of them (6.9%) were with immune thrombocytopenia (IT). The diagnosis of immune thrombocytopenia was based on the presence on unexplained fall in platelet count to <100x10⁹/L and on more than two indirect parameters: evidence of normal bone marrow function (normal or increased megakaryocytes in bone marrow), no splenomegaly and no chemotherapy within the last month. The patients with thrombocytopenia due to bone marrow suppression (lymphocytes over 80% in bone marrow) were excluded from this analysis.

Among clinical and biological variables, neither age, gender, tumor mass nor Rai stages at CLL diagnosis were significantly associated with ITP development. The ITP occurrence was significantly associated with ZAP-70 positivity (7/12; 58.3%). In contrast ZAP-70 was found in 44 of 119 B-CLL cases (27%, p=0.028). CD38 and P53 expressions was significantly higher (75% and 41.7%, respectively; p=0.038 and p=0.013, respectively) than in CLL without ITP (44% and 11.2%). Based on available FISH data, we found that among 12 cases with deletion of (11)(q22-23) region only one (9%) developed ITP. There was no statistical significance (p>0.05) between ITP development and cytogenetic deletion (13)(q14). The median overall survival of CLL-ITP patients was significantly shorter -68.6 months (95% CI: 49.5-87.6 months) than the patients without ITP -111 months (95% CI: 104.7-117.4 months; p=0.016) and overall survival dropped rapidly and was in stable rate after 12 months since the diagnosis. ITP cases had an increased risk of disease progression and mortality risk over 3 fold above the patients without ITP (p<0.001, p<0.05, respectively). CLL-ITP patients showed shorter median free of treatment period-2.08 months (95% CI 0-5.99), compared to CLL without ITP-45.10 (95%CI 36.50-53.70).

ITP-CLL is associated with a higher frequency of poor prognostic markers such CD38, ZAP-70 and P53 expressions and shortened free of treatment period and overall survival.