IMMUNOPHENOTYPING BY FLOW CYTOMETRY: CD5

CD5 IS A USEFUL MARKER TO CATEGORIZE CHRONIC B-CELL LYMPHOPROLIFERATIVE DISORDERS (B-CLPD) IN WHICH THERE IS A NEOPLASTIC ACCUMULATION OF MATURE B- LYMPHOCTES IN THE BONE MARROW, PERIPHERAL BLOOD & LYMPHOID TISSUE. MOST OF THESE PATIENTS ARE POSITIVE FOR B CELL MARKERS ON FLOW CYTOMETRY BUT A SMALL POPULATION IS NEGATIVE. THIS NEGATIVE GROUP REQUIRES CD5 TESTING. CD5 NEGATIVE B-CLPD CASES USUALLY HAVE A LEUKEMIC PHASE OF A WELL DEFINED LYMPHOMA SUCH AS MARGINAL ZONE LYMPHOMA, LYMPHOPLASMACYTIC LYMPHOMA, FOLLICULAR CELL LYMPHOMA OR HAIRY CELL LEUKEMIA.