Background: Parvovirus B19 infection is a cause of chronic anemia and red cell aplasia in patients with acquired immunodeficiency syndrome (AIDS) and in other immunocompromised hosts. Anemia in AIDS patients has a multifactorial etiology, with parvovirus B19 infection being an infrequent but nevertheless treatable cause. Therapy with intravenous immune globulin can result in rapid improvement of parvovirus-induced anemia. This treatment is expensive, therefore accurate and rapid confirmation of parvovirus infection is important in providing appropriate and cost-effective therapy.
Methods: Bone marrow samples from 2 AIDS patients with severe anemia and reticulocytopenia were studied. Bone marrow morphology and serologic studies were evaluated for parvovirus B19 infection. An immunohistochemical method using a monoclonal antibody, R92F6, to B19 capsid proteins was utilized on decalcified, B5-fixed, paraffin-embedded bone marrow biopsies. Bone marrow aspirate cells were examined by electron microscopy for evidence of viral particles. In addition, polymerase chain reaction (PCR) studies using a nested PCR assay to the parvovirus B19 viral genome were performed in a case for which fresh cells were available.
Results: Bone marrow findings included marked erythroid hypoplasia with characteristic giant pronormoblasts and intranuclear inclusions. Serologic studies were negative in one case, while the second case showed positive parvovirus B19 immunoglobulin M antibody. Immunohistochemical studies for parvovirus B19 were positive in both cases. The presence of intranuclear virions was demonstrated by electron microscopy and was confirmed by PCR analysis. Both patients were treated with intravenous immune globulin, and subsequent improvement was noted.
Conclusions: Both immunohistochemistry and PCR studies on bone marrow specimens from AIDS patients with anemia are rapid and sensitive methods for the confirmation of parvovirus B19 infection. They are valuable tools, particularly when serologic studies are negative. When PCR is not available, immunohistochemical methods can be useful. The rapid confirmation of parvovirus B19 infection will allow for early and cost-effective therapy.