肺移植後の巨赤芽球性貧血を誘発するB19パルボウイルス感染症

A man in his 50's with a history of acute lymphoblastic leukemia underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) over 20 years earlier and later developed bilateral giant pulmonary bullae, presumed secondary to pulmonary chronic graft-versus-host disease (cGVHD), requiring bilateral lung transplantation. Six months after lung transplantation, he developed rapid-onset severe normocytic anemia with reticulocytopenia. Cytomegalovirus (CMV) reactivation was initially suspected, and antiviral therapy was commenced, but the anemia persisted. Subsequent Polymerase chain reaction (PCR) testing revealed parvovirus B19 viremia, and bone marrow examination demonstrated erythroid hypoplasia with giant proerythroblasts, confirming parvovirus B19-associated pure red cell aplasia (PRCA). Treatment with intravenous immunoglobulin (IVIG) led to rapid hematologic improvement and complete recovery without recurrence. This case underscores the importance of considering parvovirus B19 infection as a potential cause of anemia in immunocompromised individuals, especially following solid organ transplantation, where overlapping viral infections and immunosuppressive agents complicate diagnosis. Early recognition and prompt IVIG therapy can result in excellent outcomes and prevent unnecessary interventions.