We have shown in two allogeneic bone marrow transplant recipients that Epstein-Barr virus can be eradicated by the BMT procedure or its complications, and that these patients are susceptible to infection with a new EBV strain. This conclusion was based on a combination of EBV serology and virus strain identification ("Ebnotyping," using the size variations of 5 EBV nuclear antigens). In the present study, we conducted a serological survey of EBV infection in 153 marrow graft recipients and their donors. Ten patients who were positive for IgG antibodies against EBV viral capsid antigens prior to BMT became completely seronegative at a median of 197 days post-BMT (range 106-320 days). Four of these patients, who had received seronegative marrow, remained seronegative during prolonged periods (222 to 2105 days). Six patients had received seropositive marrow. Two of them remained seronegative during their subsequent periods of follow-up (895 and 1437 days). An additional 10 patients showed a 100-fold or greater decrease in VCA IgG antibody titers. Their titers reached a nadir of 10 (the lower limit of positive) at a median of 134 days post BMT (range 83-386 days). The serological patterns of the above 20 patients were particularly frequent among patients with chronic graft-versus-host disease; 12 of 20 patients with decreasing VCA titers (60%) developed chronic GVHD versus only 22 of 73 patients with stable or increasing VCA titers (30%). These results suggest that GVHD may contribute to the elimination of residual EBV-carrying recipient cells. Establishment of EBV-carrying lymphoblastoid cell lines (LCL) was attempted in 60 donor-recipient pairs whose cryopreserved peripheral blood mononuclear cells were available. LCL were established from 18 of 51 EBV-seropositive marrow donors and 10 of 57 seropositive recipients prior to BMT. The same EBV strain was detected in 4 of the 6 cases in which LCL could be established from both the donor and the recipient prior to BMT. The persistence of the original EBV strain was demonstrated in a recipient of a T cell-depleted graft who showed only transient hematological recovery and no GVHD, and was associated with the persistence of B cells of recipient origin.