Transient erythroblastopenia of childhood associated with human herpesvirus type 6, variant B.

Transient erythroblastopenia of childhood (TEC) is a disorder of young children ages 3 months to 4 years that is characterized by anemia associated with reticulOcytopenia and decreased red blood cell precursors in the bone marrow aspirate (BMA). A viral cause has been suspected for TEC. Bone marrow aspirate-derived DNA from 14 children with anemia or another hematologic disorder, including two children with TEC, were analyzed by polymerase chain reaction for human herpesvirus type 6 (HHV-6) DNA and human parvovirus B19 DNA. Testing revealed an HHV-6 variant B DNA in both children with TEC but not in the children who did not have TEC. The BMAs from these two children contained large pronormoblasts and an extensive lymphoid infiltrate. We proposed that HHV-6 may be a causative agent of TEC in immunocompetent children. This hypothesis is based on the demonstrated ability of HHV-6 to suppress the formation of burst-forming units-erythroid (BFU-E) and granulocyte macrophage-colony-forming units (GM-CFU) in vitro, and in vivo in HHV-6-infected patients who undergo bone marrow transplantation.