Prolongation of rat renal allograft survival time by donor pretreatment with 8-methoxypsoralen and longwave ultraviolet irradiation of the graft (PUVA therapy).

Pretreatment of the kidney donor with 8-methoxypsoralen (8-MOP) and ex vivo longwave ultraviolet irradiation (UVA) of the kidney prolonged the subsequent survival on allogeneic recipients. The efficacy of this treatment seems to be dependent on the time and dose of UVA irradiation rather than on the dose of 8-MOP. In conclusion, PUVA treatment is effective in reducing the immunogenicity of the rat kidney allograft, although the mechanism remains unclear. These experimental findings are new and preliminary results in clinical human kidney transplantation are favourable.