Parvovirus infection causing red cell aplasia and leukopenia in rheumatoid arthritis.

A case of acute parvovirus B19 infection causing fever, anaemia, leukopenia, and red cell aplasia, in a patient with chronic rheumatoid arthritis is described. The patient had received low doses of corticosteroids for several years, and a small dose of methotrexate recently. There was no evidence of haemolytic anaemia, iron deficiency or drug toxicity. Recovery was associated with the development of antibodies against parvovirus B19, and clearance of viraemia as detected by the polymerase chain reaction. Possible mechanisms for the development of leukopenia are discussed, but there was no evidence for haemophagocytosis.