Flowcytometry in Chronic B-Cell Lymphoproliferative Disorders: A Retrospective Study from a Tertiary Oncology Centre, Trivandrum, India

Abstract

Introduction: Chronic B-Cell Lymphoproliferative Disorders (B- CLPD) are malignant neoplasms of B lymphocytes characterised by accumulation of mature B lymphocytes in the Bone Marrow (BM), peripheral blood, and lymphoid tissues. Multiparameter flowcytometry has become a powerful tool in diagnosing B-CLPD that identifies a clonal light-chain restricted population expressing B-cell markers. Aim: To study the morphologic and immunophenotypic profile of B-CLPD by flowcytometry and to determine the incidence of various subtypes. Materials and Methods: All consecutively diagnosed cases of chronic B lymphoproliferative disorders at Regional Cancer Centre, Trivandrum, Kerala, India from 1st December 2016 to 30th November 2018 were retrospectively analysed and studied. Diagnosis of CLPD was made based on peripheral smear and BM aspiration and immunophenotyping by flowcytometry. Flowcytometry was performed using BD FACS Verse flowcytometer. The results of immunophenotyping by flowcytometry were reviewed and analysed. Results: During the study period, 231 cases were diagnosed as Chronic Lymphoproliferative Disorder (CPLD), of which 209 cases were B-CLPDs. Male to female ratio (M:F) was 2:1. In the present study, incidence of Chronic Lymphocytic Leukaemia (CLL) was 138 cases (66.03%), Follicular Lymphoma (FL) was 14 cases (6.7%), Hairy Cell Leukaemia (HCL) was 11 cases 5.26% and Mantle Cell Lymphoma (MCL) was 9 cases, (4.31%). Prolymphocytic leukaemia and splenic Marginal Zone Lymphoma (MZL) constituted 4 cases (1.91%) each. Some cases of B-CLPDs had no definite diagnoses which were diagnosed as CD5 positive B-CLPD unclassified 13 cases (6.22%) and CD5 negative B-CLPD unclassified 16 cases (7.66%). Conclusion: Flowcytometry has helped in definite subtyping of B-CLPD in most cases. Most common subtype in the present study was CLL. CD5+/CD23+ is highly specific for diagnosing CLL. CD200 is revealed to be an excellent marker to distinguish CLL from MCL.