Persistent parvovirus B19 infection in an older patient with rheumatoid arthritis receiving immunosuppressive therapy: A case report and literature review.

An 84-year-old man with rheumatoid arthritis undergoing treatment with methotrexate presented with fever, general fatigue, and appetite loss. He had a 3-month history of unexplained normocytic anaemia with reticulocytopenia. Bone marrow examination revealed erythroid hypoplasia with giant pro-erythroblasts, leading to a diagnosis of parvovirus B19 infection. In this case, intravenous immunoglobulin therapy improved the patient's anaemia and systemic symptoms. Six months after the treatment, parvovirus B19 DNA remained detectable using polymerase chain reaction; however, the viral load had markedly decreased, indicating a favourable virological response. Twenty cases of parvovirus B19 infection in older adults (aged ≥65 years) were identified in the literature. Immunocompromised older patients frequently develop persistent parvovirus B19 infections that require treatment with intravenous immunoglobulin therapy, whereas persistent infections are not observed in immunocompetent older individuals. Therefore, this case suggests that clinicians should be aware of persistent parvovirus B19 infection in older immunosuppressed patients who develop unexplained anaemia with reticulocytopenia. Moreover, intravenous immunoglobulin therapy may be considered as an effective therapeutic option for persistent parvovirus B19 infection in immunocompromised patients.