The relevance of more sensitive ancillary crossmatch techniques in predicting early cadaver renal graft outcome.

ABSTRACT

The predictive value of varying levels of antibody activity, its class and antigen specificity in sera of 81 recipients of cadaver renal allografts was evaluated. Recipients for transplantation were selected on the basis of a negative dye uptake T-cell crossmatch, after which the more sensitive 51Cr release technique was employed in a blind study using unseparated donor target cells. Recipient sera with peak panel reactivity and current samples were evaluated before and after reduction with dithiothreitol to destroy the IgM subclass. Double absorption with pooled platelets allowed antibodies against HLA class I antigens to be distinguished from those against HLA class II/non-HLA antigens. Optimal levels of cytotoxicity were established, giving a sensitivity of 73%. Data were assessed in terms of positive predictive value, and showed that conventional T-cell crossmatching is adequate for the primary transplant group, but more sensitive ancillary tests are indicated for regrafts. In this category of patients, IgG antibodies, whether against HLA class I antigens or HLA class II/non-HLA antigens, were highly predictive of early graft loss (positive predictive value 50%-100%). Using this protocol for patient selection, 1-month graft survival would have improved from 73% to 96%.