Post-COVID-19 pure red cell aplasia: A case report and literature review.

Pure red cell aplasia is a rare hematologic disorder characterized by severe normocytic anemia, reticulocytopenia, and absence of erythroid precursors. Since the COVID-19 pandemic, pure red cell aplasia has emerged as an uncommon post-infectious complication, likely driven by immune dysregulation. A 72-year-old man developed transfusion-dependent anemia several weeks after a mild COVID-19 infection. Laboratory evaluation revealed normocytic anemia (hemoglobin of 7.0 g/dL) with profound reticulocytopenia, and bone marrow biopsy showed markedly reduced erythropoiesis with preserved granulopoiesis and megakaryopoiesis. Secondary causes, including nutritional deficiencies, hemolysis, autoimmune disease, parvovirus B19, and hematologic malignancy, were excluded. The patient failed to respond to intravenous immunoglobulin, corticosteroids, and cyclosporine, achieving only a transient partial remission. Rituximab therapy was subsequently initiated and resulted in complete hematologic recovery and sustained remission at 1 year. COVID-19-associated pure red cell aplasia is a rare but clinically important complication. Clinicians should consider it in patients with severe post-COVID anemia, and rituximab may be effective in cases refractory to standard immunosuppressive therapy.