A PRETRANSPLANT POSITIVE T CELL FLOW CYTOMETRY CROSSMATCH PREDICTS REDUCED GRAFT SURVIVAL IN RENAL ALLOGRAFT RECIPIENTS RECEIVING THYMOGLOBULIN INDUCTION.

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A PRETRANSPLANT POSITIVE T CELL FLOW CYTOMETRY CROSSMATCH PREDICTS REDUCED GRAFT SURVIVAL IN RENAL ALLOGRAFT RECIPIENTS RECEIVING THYMOGLOBULIN INDUCTION.
A. J. Norin, Ph.D. , M. O. Salifu, MD. , M. Mondragon-Escorpizo MD , S. Konar BS , D. Hochman BS , N. Sumrani MD , M. Markell MD , T. Brown , A. Alam MD , Y. Woredekal MD , J. Hoon MD , E. Friedman MD and D. Distant MD . Brooklyn NY, SUNY Downstate Medical Center, 11203, Transplant Immunology & Immunogenetics Laboratory ; Medicine, Division of Nephrology and Surgery, Division of Organ Transplantation .

We previously reported that the poor outcome of a positive B cell flow cytometry crossmatch (FCXM) in sensitized patients could be overcome by induction therapy with anti - lymphocyte globulin. In the current study we reviewed all renal transplants at our center who received thymoglobulin induction between 1998 and 2001 (mean follow up, 1.7±1.2yrs, range 9-52 mos.) to determine the association of a positive T cell and B cell FCXM (FCXM, T+ B+) compared to a FCXM, T- B+) and a FCXM, T- B-. All recipients were CDC (Amos One –Wash) XM negative against the donors’ T cells.. Of 139 patients, 33% were FCXM, T+ B+, graft survival = 71% (p=0.047), 23% were FCMX, T- B+, GF= 88% and 41% were FCMX, T- B-, GF = 89%. Cox univariate analysis showed an independent increased risk of graft failure for a FCXM, T+ (hazard ratio 2.3 [95% CI 1.04-5.3]; p=0.04). A FCXM, T+ was associated with retransplantation, PRA > 30% and a graft from a deceased donor. Differences among the above FCXM study groups in age, gender, race and HLA matching were not observed. We conclude that renal transplant recipients with a T cell flow cytometry positive crossmatch but not a B cell positive, T cell negative flow cytometry crossmatch are resistant to treatment with thymoglobulin induction therapy and therefore exhibit reduced allograft survival . The etiology of reduced graft survival in patients with a low level of anti -HLA class I antibody is unknown but a T cell+ FCXM is clearly a marker of enhanced humoral and/or cell mediated immune reactivity against the allograft since it is associated with sensitization.