Augmented natural killer cell activity during neonatal graft-versus-host disease is of predominantly donor origin

Natural killer cells have been postulated to play a role in the immunopathogenesis of graft-versus-host disease (GVHD). This is based on reports of augmented natural killer (NK) activity, both in animal models and in humans. It has not been elucitated from previous reports, however, whether the cells mediating this activity are of donor or recipient origin. We have investigated the origin of the effector cells using highly specific antisera. Our results indicate that the augmented lytic activity seen during the course of GVHD is mediated primarily by donor lymphocytes. Depletion with anti-Class I antisera followed by immuno-staining with anti-asialo GM-1 indicate that the effector cells are also asialo GM-1 positive. We report here that the augmented non-specific lytic activity seen during GVHD is mediated by asialo GM-1 positive lymphocytes predominantly of donor origin.