CLL-like B-lymphocytes are systematically present at very low numbers in peripheral blood of healthy adults

Abstract

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in the Western world. The disease is typically diagnosed in adults >40 years old, who show an expansion (>5 × 109 cells per l) of clonal B-cells with a unique CD5+, CD23+, B-cell receptor (BCR)low immunophenotype in peripheral blood (PB) and bone marrow, frequently in association with involvement of other lymphoid tissues, disease symptoms and a heterogeneous clinical outcome.