Analysis of the immune status in the recipients with long-term well-functioning kidneys allografts

The immune status of thirteen living and related kidney transplant recipients with stable allografts were examined. The immunological assays consisted of a mixed lymphocyte reaction (MLR), cell-mediated lympholysis (CML) assay, interleukin-2 (IL-2) production in mixed lymphocytes culture (MLC) and IL-2 receptor (IL-2 R) expression on MLC cells. The suppression rates of the monoclonal antibodies (mAbs) against IL-2 R were tested on MLRs. The stimulation indices (SI) of the MLR against both donor and third-party cells increased compared with those of pretransplantation. The MLC responder cells stimulated by donor cells produced detectable amounts of IL-2, these amounts were lower than those by third-party cells. The MLC cells against donor cells expressed IL-2 R alpha and beta chains to the same degree as those against third-party cells. Anti-IL-2 R mAbs equally inhibited the MLRs between recipient and donor or third-party cells. Cytotoxic T lymphocytes (CTL) against donor cells were not generated, even with the addition of recombinant IL-2 in any of recipients except one, while anti-donor CTL had been detected prior to transplantation and the CTL against third-party cells were induced in posttranspalnt CML assays. These results indicate that the clonal anergy phenomenon might mediate the specific CTL unresponsiveness observed in kidney transplant recipients and the anergy phenomenon might serve in the long-term acceptance of allograft.