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 associated with an increased risk of graft-versus-host disease (GVHD) compared with HLA-identical sibling donors. It has been suggested that the level of patient-specific CTL precursors (CTLp) present in matched unrelated donors correlates with the incidence and severity of GVHD after BMT. This study group consisted of 17 patients who all received unmanipulated bone marrow from an HLA-A,B,DR-matched unrelated donor. Patient-specific CTLp frequencies were estimated in the donor before transplant. The CTLp frequencies were then compared with the incidence and severity of GVHD experienced by the patient after transplantation. Statistical analysis revealed no correlation between donor precursor frequencies and the patient developing clinically significant acute GVHD after transplantation (X2 = 1.16). This study suggests that caution should be used before the inclusion of the CTLp frequency result in the clinical decision of selecting the most suitable matched unrelated donor for BMT. CTLp frequency does not correlate with either the incidence or severity of GVHD after matched unrelated donor BMT.