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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Acute Disease, Graft Rejection, Histocompatibility Testing, Humans, Immunosuppressive Agents, Kidney Transplantation, Lymphocyte Activation, Lymphocyte Culture Test, Mixed, T-Lymphocytes, Cytotoxic, T-Lymphocytes, Helper-Inducer, Transplantation, Homologous.
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Does donor-specific T-cell reactivity identify kidney transplant patients in whom immunosuppressive therapy can be safely reduced? Context: To reduce the side effects of long-term immunosuppressive therapy, stable renal transplant patients were routinely converted from cyclosporine to either azathioprine or mycophenolate mofetil. Thereafter, the azathioprine and mycophenolate mofetil dose was reduced to 75% at 4 months and to 50% at 8 months after conversion. We questioned whether the T-cell reactivity before conversion was able to predict which patients could be safely converted and tapered in their immunosuppressive load, while remaining free from acute rejection. Before conversion, the T-cell reactivity of peripheral blood mononuclear cells against donor and third-party spleen cells were tested in mixed lymphocyte cultures. We measured the frequency of donor and third-party reactive helper T-lymphocyte (HTLpf) and cytotoxic T-lymphocyte (CTLpf) precursors and their avidity for HLA class I antigens using limiting dilution analysis. Peripheral blood mononuclear cells were also stimulated with tetanus toxoid to test the general immune response. The tetanus toxoid response, reactivity to donor and third-party cells as measured in mixed lymphocyte cultures and HTLpf, and the avidity of cytotoxic T-lymphocyte precursors were not predictive for the development of acute rejection. However, significant differences were found in donor-specific CTLpf before conversion, between patients with and without acute rejection after conversion in immunosuppression. The donor-specific CTLpf was significantly lower in patients without compared to those with acute rejection (P=0.01). Additionally, when no CTLpf was detectable before conversion, acute rejection did not occur after conversion. Acute rejection was only diagnosed in patients with detectable CTLpf before conversion.
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The number of donor-specific cytotoxic T-lymphocytes identifies patients in whom the immunosuppressive load can be safely reduced. Final Decision: yes