LATE GRAFT FAILURE DUE TO DUAL BONE-MARROW INFECTION WITH VARIANT-A AND VARIANT-B OF HUMAN HERPESVIRUS-6

Hematopoietic effects of human Herpesvirus-6 (HHV-6) infection followi ng bone marrow transplantation (BMT) include delayed engraftment and e arly myelosuppression. Variant A has not been isolated after BMT. A ca se of graft failure is reported following an HLA-identical BMT for chr onic myelogenous leukemia (CML) in chronic phase. Evaluation of bone m arrow during the period of graft failure revealed variants A and B of HHV-6 by culture, immunofluorescence, polymerase chain reaction (PCR), and immunohistochemistry. Evidence for other cases of graft failure, including cytomegalovirus (CMV), could not be found. A hypothesis is p roposed that late graft failure in this case was clue to variant A of HHV-6.