Comparison of the HL-A phenotypes of lymphocytes and kidney cells determined by the fluorochromasia cytotoxicity assay

Abstract

Correlation of leukocyte typing with homograft survival suggests that HL-A typing of white blood cells reflects the histocompatibility factors of the kidney, yet some apparently well-matched kidneys are rejected. The latter results may, in part, reflect inadequacies of typing techniques, incomplete expression of HL-A factors on white blood cells as compared with the cells of the rejected organ, or isoantigens not shared with leukocytes. In this study the kidney cells and lymphocytes (from blood or nodes) of 14 individuals were typed for HL-A factors 1, 2, 3, 5, 7, 8, 9, and 12, and factors 4a and 4b by fluorochromasia cytotoxicity. Biopsied kidney cells were prepared with 0.25% trypsin and typed fresh, after varying periods in monolayer culture or after storage in liquid nitrogen, in all cases resulting in cells which were pleomorphic but uniform in reactivity. Reproducibility of lymphocyte typing was 99%, and of kidney cell typing, 93%. The 4a factor was detected on the lymphocytes but not the kidney cells of four individuals. HL-A7 and HL-A8, in contrast, were detected on kidney cells and not lymphocytes of four and three individuals, respectively. Results were consistent within the groups of individual sera used to detect each factor. The HL-A factors detected on both kidney cells and lymphocytes never resulted in more than two alleles at each genetic sublocus. Several examples of post-rejection sera have reacted with donor kidney cells but not with lymphocytes. Kidney cells may thus be useful in compatibility tests to aid in selection of donors for a retransplant. The ability to store donor kidneys by perfusion provides time to employ kidney cells for typing and in compatibility tests, and the use of a standard cytotoxic assay makes their routine use practical. Typing kidney cells as well as lymphocytes thus offers an approach to more complete and accurate HL-A phenotyping.