CYTOTOXIC T-LYMPHOCYTE PRECURSOR FREQUENCY DOES NOT CORRELATE WITH EITHER THE INCIDENCE OR SEVERITY OF GRAFT-VERSUS-HOST DISEASE AFTER MATCHED UNRELATED DONOR BONE-MARROW TRANSPLANTATION

BMT from matched unrelated donors or mismatched family members is asso ciated with an increased risk of graft-versus-host disease (GVHD) comp ared with HLA- identical sibling donors. It has been suggested that th e level of patient-specific CTL precursors (CTLp) present in matched u nrelated donors correlates with the incidence and severity of GVHD aft er BRIT This study group consisted of 17 patients who all received unm anipulated bone marrow from an HLA-A,B,DR-matched unrelated donor. Pat ient-specific CTLp frequencies were estimated in the donor before tran splant. The CTLp frequencies were then compared with the incidence and severity of GVHD experienced by the patient after transplantation. St atistical analysis revealed no correlation between donor precursor fre quencies and the patient developing clinically significant acute GVHD after transplantation (X(2)=1.16). This study suggests that caution sh ould be used before the inclusion of the CTLp frequency result in the clinical decision of selecting the most suitable matched unrelated don or for BMT. CTLp frequency does not correlate with either the incidenc e or severity of GVHD after matched unrelated donor BMT.