[Immunological analysis of mixed lymphocyte culture reaction inhibitory factor induced by donor specific blood transfusions in potential kidney transplant patients].

There is now overwhelming evidence that preoperative donor specific blood transfusions (DST) improve kidney graft survival remarkably. However, the exact mechanism is as yet unknown. In this study, we compared a DST group with a non-DST and investigate the mechanism of the beneficial effect of DST by using MLR, CML, and the MLR inhibition test. In the DST group, the severity of acute rejection and MLR reactivity was decreased after DST in most cases, but there was no such tendency in CML reaction. In the MLR inhibition test, the MLR serum inhibitory factor was induced in 70% of the cases (7 out of 10) received 3 times of DST. All of them were directed against recipient cell (auto-lymphocyte) and not to the blood donor cell and its activity was found in IgG fraction. The specificity to the stimulator cell was also found in 43% (3 out of 7). The results of MLR inhibition tests were well correlated with clinical findings and changes of MLR and CML. In positive cases of MLR inhibition tests, acute rejection occurred in 14% (1 out of 7), CML decreased in all (3 out of 3) and MLR decreased in 83% (5 out of 6) after DST. On the contrary, in negative cases, acute rejection occurred in 67% (2 out of 3), CML increased in all (3 out of 3) and MLR increased in 67% (2 out of 3). These results suggested that antibodies directed against recognition sites on auto-lymphocytes, so called anti-idiotypic antibodies, will be induced by 3 DST and play an important role in the prolongation of graft survival.