The responses to dermal antigen testing to a variety of antigens were measured in patients on regular dialysis. Forty-eight patients have received renal allografts and graft survival was assessed at 6 months. The antigens used were mumps, monilia, streptokinase/streptodornase, tuberculin and dinitrochlorobenzene (DNCB). The responses to these antigens were recorded using standard methodology. The response failed to correlate with graft survival in these patients when compared singly or in combination. Matching at the HLA-B locus was also correlated with graft survival. Of 31 patients with a match at this locus, 22 (71 per cent) have functioning grafts at 6 months, compared with only 4 of 13 (31 per cent) of patients with no match at the B locus (P less than 0.05). When matching at the B locus and DNCB scores were taken in combination, it became evident that those patients with no match at the B locus and low DNCB reactivity all rejected their kidneys within 4 months of transplantation.