Hypothesis: Engrafted Human Bone Marrow and Blood Cells in Culture

Lymphoblasts appearing in immunosuppressed patients after bone marrow transfusion are compared to thosethat can be established in vitro as permanent lymphoid cell lines. It is suggested that Epstein-Barr virus (EBV)could be responsible for the recurrent "lymphoblastic leukemia" inthese patients and that the transplanted cells may be a clone of nonmalignant cells that has becomecapable of growing without normalrestraints. It is important that in futurepatients the transplanted cells be characterized as to morphology, chromosome constitution, relative clonabilityand transplantability, the presence ofEBV, T or B cell-like traits, and theirgrowth potential in immunosuppressedheterologous hosts. The antibody titerto EBV should be measured beforeand after leukocyte transfusion.