Chronic Lymphoid Leukaemias

This topic explores the spectrum of Chronic Lymphoid Leukaemias (CLL), diseases characterised by the accumulation of mature lymphocytes in the blood. It is designed for tertiary students in Zambia pursuing specialisation in haematology or laboratory medicine. The focus is primarily on B-cell diseases, especially Chronic Lymphocytic Leukaemia (CLL), covering its epidemiology, genetic predisposition, and pathogenesis centred on defective apoptosis. The clinical presentation is detailed, ranging from incidental lymphocytosis to symptomatic lymphadenopathy, splenomegaly, and immunosuppression. Diagnostic criteria, including absolute lymphocytosis with a characteristic immunophenotype (CD19+, CD5+, weak surface immunoglobulin), are emphasised. The topic also explains prognostic markers like CD38 and ZAP70, and the utility of staging systems (Rai, Binet). Other B-cell entities like Prolymphocytic Leukaemia (PLL) and Hairy Cell Leukaemia (HCL) are contrasted based on morphology and clinical features. A brief overview of key T-cell leukaemias (e.g., T-PLL, Adult T-cell Leukaemia/Lymphoma) is also included. For university and college learners, understanding the indolent nature, diagnostic workup, and monitoring of these chronic leukaemias is essential for clinical management and laboratory diagnosis. This knowledge is vital for exam success and for practising in settings where these conditions are increasingly diagnosed.