title: Immature T lymphocytes in the peripheral blood of bone marrow transplant recipients.
abstract: Recipients of allogeneic bone marrow transplants are characterized by an immunodeficiency of varying intensity and duration. We have previously demonstrated the presence of in vivo activated suppressor T lymphocytes in immunodeficient patients with chronic graft-versus-host disease. To determine the basis of the immunodeficiency of transplant recipients early after transplantation, the lymphocytes of transplant recipients were analyzed phenotypically by E-rosette formation and staining with monoclonal antibodies (OKT-3, -6, and -8) and functionally by their blastogenic response to mitogens. Only 15% of transplant recipients' assays 0-3 months and 16% of assays 3-12 months following transplant were in the normal range. Transplant recipients during the first year after transplantation were characterized by an increased percentage (57%) of patients with a normal percentage of E-rosette-forming cells but reduced PHA responsiveness. In vitro coculture experiments demonstrated that their lack of PHA responsiveness was not due to the presence of in vivo activated suppressor cells or a decrease in mitogen-presenting cells. Staining with monoclonal antibodies revealed that the T lymphocytes from the majority of recipients at 0-3 months following transplantation contained a percentage of OKT8-positive cells greater than or equal to the percentage of OKT3-positive cells. This pattern (OKT8 greater than or equal to OKT3) was not found in the peripheral blood T lymphocytes of normal people but was found in 13 of 15 thymuses. Monoclonal staining with OKT6, a thymocyte-specific antibody, revealed positive staining of more than 10% of the peripheral blood leukocytes in the majority of recipients 0-3 months following transplantation, compared with only a few normals. We concluded that the circulating T lymphocytes of transplant recipients are phenotypically and functionally immature, and that their relative immaturity contributes to the transplant recipients' immunodeficiency.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology; D001854:Bone Marrow Cells; D016026:Bone Marrow Transplantation; D005455:Fluorescent Antibody Technique; D006801:Humans; D008213:Lymphocyte Activation; D013601:T-Lymphocytes; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal