Histocompatibility testing for kidney transplantation: an update

Histocompatibility testing prior to kidney transplantation is an established necessity. Recipient sensitization to HLA specificities affects the efficacy of the lymphocytotoxic cross-match and influences the achievable HLA mismatch. Within Europe most cadaver donor kidneys are allocated on the basis of minimum histocompatibility mismatch contrasting with the North American system which allows for exchange of kidneys only where there is no detectable donor/recipient mismatch. There is also a contrast between the immunosuppression protocols used in these continents with, in general, more aggressive regimens used in North America. In the 1990s there has been considerable refinement in the techniques available to histocompatibility laboratories for definition of HLA phenotypes and genotypes and some obstacles to successful transplantation have been overcome. We review some of these changes with particular reference to our own experience.