Pretransplant soluble CD30 (sCD30) is a predictor of kidney graft outcome. Its status as a predictor of heart transplant (HT) outcome has not been established. We have studied this question by assessing sCD30 levels and the number of (CCAT)n repeats of the microsatellite in the CD30 promoter region, which is able alone to repress gene transcription, in the sera of 83 HT patients and 77 of their donors. sCD30 was non-significantly increased in the patients, whereas there were no differences in the CD30 microsatellite allele frequencies. A negative correlation between the number of (CCAT)n and sCD30 levels was evident in the donors. Patients with pretransplant sCD30