Children with severe aplastic anaemia should be tested for B19 parvovirus infection, according to a small study that has shown that the two are associated. The study of 30 children with severe aplastic anaemia and healthy matched controls detected active or recent infection with B19 parvovirus with specific viral DNA or antibody, or both, in six anaemic children.

Two of the six had had previous erythema infectiosum—an infection associated with parvovirus B19. The four others had asymptomatic B19 parvovirus infection. Two children died and four recovered with combination treatment with horse antilymphocyte globulin, cyclosporin, and intravenous immunoglobulin.

The children, 18 boys and 12 girls, median age 6.8 years (range 1–14 years) were admitted with severe aplastic anaemia between April 1995 and December 1996. Healthy controls were selected, matched for age, community, and time of presentation. Parvovirus B19 DNA was detected by nested PCR of lysed serum samples and antibody against parvovirus B19 by ELISA.

Human parvovirus B19 is already linked with many other conditions. The commonest and most serious complication is severe aplastic anaemia in sickle cell anaemia and hereditary sphaerocytosis. Asymptomatic B19 parvovirus infection has been recorded with childhood severe aplastic anaemia only in one previous case.

How the virus causes severe aplastic anaemia is not clear. It may act directly, targeting cell lines in the bone marrow involved in blood formation through its attachment to P substance or by immunological means through interference with regulation of the phagocytic system by interferon γ.