Chronic lymphocytic leukaemia (CLL) is a clonal haematological disorder consisting of immunologically inept, small, monomorphous and well-differentiated B-lymphocytes that aberrantly express the antigens CD5 and CD23 on their surfaces.1 A sustained (≥ 3 months) monoclonal B-lymphocytosis of ≥ 5 × 109/L in the peripheral blood, with characteristic morphological and immunophenotypic features, is required to establish the diagnosis of CLL.2 This evidence concerns the gene FCER2 and B-cell chronic lymphocytic leukemia.