In 28 healthy adults aged 19 to 52 years, normal values of the TG lymphocytes amount to 17.8 +/- 2.3% and 253.1 +/- 96.1 per microliters respectively and the non TG/TG ratio to 4.72 +/- 0.82. When compared with normal controls, patients on dialysis had a disturbed non TG/TG ratio (4.72 +/- 0.82 vs. 6.00 +/- 1.94, p less than 0.05). During the first posttransplant month the total TG cell count was significantly reduced, but the relative TG cell count did not significantly differ from the normal as well as praeoperative TG cell count. In connection with rejection crises we could not observe any changes in the TG subset. Beside this general dynamics we observed two different kinds of changes of the non TG/TG ratio in the individual posttransplant course. Either the non TG/TG ratio were lower than praetransplant or higher. In 9 out of 9 cases the lowering of the non TG/TG ratio (that means a relative or absolute increase of Fc-IgG receptor bearing T cells) were connected with a good graft function. In 4 out of 6 cases a postoperative increase of the non TG/TG ratio were connected with an early graft failure. A change of T subsets for the benefit of TG cells which includes suppressor cells seems to be favourable with regard to the graft survival. Therefore, we think the determination of the prae- and posttransplant non TG/TG ratio is of some prognostic value.