Haemolytic Anaemia; Beyond Sickle Cell Anaemia: A Case Series of Patients With Paroxysmal Nocturnal Haemoglobinuria in Kenya.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, acquired clonal haematopoietic stem cell disorder characterised by intravascular haemolysis, thrombosis and bone marrow failure. It results from an acquired somatic mutation in the X-linked phosphatidylinositol glycan Class A (PIGA) gene, leading to deficiency of glycosylphosphatidylinositol-anchored complement regulatory proteins, particularly CD55 and CD59, and uncontrolled complement-mediated haemolysis. Although sickle cell disease is the most prevalent haemolytic anaemia in Kenya, other aetiologies need to be considered. We describe a case series of seven patients with PNH confirmed by fluorescent aerolysin reagent (FLAER) flow cytometry. Patients were young, aged 17-38 years (median age of 23 years), with a predominance of males. All presented with recurrent symptomatic anaemia requiring multiple transfusions. One patient had pancytopenia due to very severe aplastic anaemia, while another presented with mesenteric vein thrombosis complicated by bowel ischaemia. All patients had large PNH clones on flow cytometry. Management was largely supportive due to a lack of access to complement inhibitor. These included blood transfusion, folate supplementation, cautious iron replacement and anticoagulation where indicated. One patient underwent successful matched sibling allogeneic stem cell transplant. This series highlights the presence of PNH in Kenya, diagnostic delay and the need for improved access to definitive testing and therapy in resource-limited environments.