154 Annual AACHT Meeting, 1985

SENSITIVITY OF AHG-CDC AND FLOW CYTOMETRY IS COMPARABLE IN DETECTING HLA ALLOANTIBODIES. J. Oldfather, B. Duffy, T. Fuller, A. Fuller, and G. Rodey; American Red Cross MO/IL Regional Blood Services. Washington University School of Medicine. St. Louis MO: and Massachusetts General Hospital. Boston. MA

Flow cytometry (CF) is a complement-independent cross-matching technique that can be used to detect lymphocytotoxic antibodies in dialysis patients. The pro- cedure is more sensitive than standard complement-dependent lymphocytoto×- icity (CDC) cross-matches, but there are few published comparisons of CF cross- matches with the antiglobulin-augmented lymphocytotoxic assay (AHG-CDC ~ the most sensitive of the tymphocytotoxicity assays. In this study we compared CDC and A H G - C D C assays with the CF technique. We studied an alloantiserum that was differentially absorbed and known to contain a single public antibody against HLA-A10,A 11. The antiserum displayed the CY N A P phenomenon and reactivity was only demonstrable by AHG-CDC, but not by CDC. This antiserum was tested by all three techniques at dilutions ranging from neat to V,2~ against four relevant and seven irrelevant targets. Target cells were normal human T lymphocytes purified from peripheral whole blood by nylon wool. All three techniques were performed simultaneously, using the same serum dilutions and cell preparations. As expected, all serum/cell combinations were negative by CDC. All relevant cells were positive by A H G - C D C with titers ranging from L;, to ~/4. Reactivity with irrelevant cells was negative ~less than 10%~ by AHG- CDC. Titers determined by CF on the four positive serum/cell combinations were 2-,2-,2-, and eight-fold higher than AHG-CDC. Serum/cell combinations that were negative by A H G - C D C were also negative by CF. While CF is clearly a more sensitive technique than CDC, it does not appear to be significantly more sensitive than AHG-CDC, as reported by Garavoy et al. (Transplant Proc I5:1939~ 1983). This study suggests that AHG-CDC and CF assays have comparable ranges of sensitivity in detection of HLA antibodies. CF is a rapid and sensitive cross- matching procedure, but properly performed A H G - C D C is a practical alternative procedure for laboratories without CF technology.

THE FLOW CYTOMETRY CROSS-MATCH IN CADAVERIC KIDNEY TRANSPLANTA~ TION. M.R. Garovoy, C. Stabile, JIP. Bernhardt, B.W. Colombe, W. Amend, F. Vincenti. j Melzer, N. Feduska, and O. Salvatierra; University of California, San Francisco, CA

We previously demonstrated that cross-match testing using the fluorescent ao tivated cell sorter (FACS XM) is up to 250 times more sensitive than conventional cross-matches. In this retrospective study we evaluated the role of the FACS cross-match on graft survival of 117 cadaveric kidney recipients treated with conventional immunosuppression (steroids and azathioprine). Although all pa- tients were T cytotoxic (antiglobulin) cross,match negative at the time of the transplant, 38% had an anti-T cell antibody by FACS XM. Overall, the estimated graft survival of transfused patients at 1 yr was: FACS T negative ~n = 68): 7 0 ~ survival (p ~ 0.04); FACS T positive (n -- 35): 48% survival (p ~- 0.04). The graft survival in patients whose screening revealed panel reactive antibody > 10% was: FACS T negative (n -- 19): 72% survival (p ~ 0.04); FACS T positive (n = 26): 36% survival (p -~ 0.04). There were no statistically significant differences between patients who were B warm antibody (Ab) p0 s. or neg. How- ever, when stratified according to FACS XM, those who were B warm Ab neg. and FACS T neg. had 72% survival while those with B warm Ab poS. and FACS T pos. had 40% survival (p -~ 0.04). These results suggest that the FACS XM measures a relevant state of presensitization whose detection may facilitate imp. proved graft survival.