Immunophenotypic Characterisation of Lymphoid Malignancies Using Flow Cytometry at a Tertiary Centre in Lagos State, South West Nigeria

Accurate immunophenotypic classification of lymphoid malignancies is essential for directing targeted therapy and predicting prognosis, yet flow cytometry capacity in Nigeria remains largely confined to a few centres in major cities. This study immunophenotypically characterised lymphoid malignancies diagnosed at Lagos University Teaching Hospital, Lagos State, South West Nigeria, using multiparameter flow cytometry. A prospective cross-sectional study enrolled 100 patients with suspected lymphoid malignancies presenting between 2022 and 2024. Peripheral blood, bone marrow aspirates, and lymph node fine-needle aspirates were immunophenotyped using a panel of CD markers including CD10, CD19, CD20, CD23, CD3, CD5, CD38, and FMC7. Diagnoses were correlated with morphological and cytogenetic findings. B-cell malignancies predominated at 72.0%, with B-cell chronic lymphocytic leukaemia the most common at 34.7%, followed by diffuse large B-cell lymphoma at 18.1% and follicular lymphoma at 12.5%. T-cell neoplasms represented 17.0% of cases. Immunophenotyping reclassified or refined morphological diagnosis in 28.0% of cases. CD20 expression was confirmed in 88.9% of B-cell malignancies, supporting rituximab eligibility. Aberrant antigen expression was documented in 22.0% of cases, emphasising the importance of comprehensive panel design. The study provides the first systematic immunophenotypic profile of lymphoid malignancies at a Lagos teaching hospital and advocates for expansion of flow cytometry infrastructure and expertise to additional tertiary centres across South West Nigeria. Keywords: flow cytometry, lymphoid malignancies, immunophenotyping, CLL, Lagos State