The diagnosis of CLL is based on the finding of peripheral lymphocytosis of over 5 (or 10) x 10(9)/L presenting the CD19, CD5, CD23 phenotype and a weak monoclonal expression of membrane immunoglobulins. The CD38 expression is observed in half of the cases and is correlated with the unmutated status of the Ig V gene. Bone marrow biopsy should only be performed before starting treatment or if necessary for the differential diagnosis with other low-grade lymphomas. This differential diagnosis is based on the morphology of circulating lymphocytes, their immunophenotypes and pattern of bone marrow infiltration.
Chronic lymphocytic leukemia; diagnosis; phenotype; lymphoproliferative syndromes
