B-cell chronic lymphocytic leukemia with aberrant CD8 expression: genetic and immunophenotypic analysis of prognostic factors.

B-cell chronic lymphocytic leukemia (B-CLL) is phenotypically characterized by cell surface co-expression of CD19, CD20, CD5, and CD23. However, the concomitant presence of other antigens distinctive of a particular leukocyte subset, e.g. T cells, is an unusual finding in B-CLL. In the present report, a case of B-CLL with aberrant expression of the T-cell-associated antigen CD8 is described. Flow cytometric analysis of the patient's cells demonstrated lack of CD38 expression, and cytogenetic analysis by FISH did not show any abnormalities of chromosomes 17p, 11q, and 12. Furthermore, the B-CLL cells expressed only low levels of the tyrosine kinase ZAP-70, which was in agreement with the mutated status of the immunoglobulin heavy-chain variable-region gene (IgVH). In summary, the determined profile of prognostic markers together with the highly stable and indolent disease in the described patient suggest a good prognosis of B-CLL with aberrant CD8 expression.