PARVOVIRUS-B19 INFECTION AND BONE-MARROW TRANSPLANTATION

Parvovirus B 19 lytically infects erythroid progenitor cells and thereby causes cessation of erythropoiesis in infected individuals. Anemia develops only if red cell turnover is increased, as in patients with chronic hemolysis (transient aplastic crisis). In addition to transient marrow failure, B 19 can cause chronic anemia and, rarely, pancytopenia in immunodeficient patients who are not able to mount an adequate immune response to clear the virus. Bone marrow transplantation, although causing significant immunosuppression, is rarely complicated by symptomatic B 19 infection. This is probably due to effective passive immunotherapy by immunoglobulin infusions immediately after transplantation and early reconstitution of antibody responses after uncomplicated transplantation.