4.2
#119
TRANSPLANT TEST SENSITIVITY: HOW MUCH IS NECESSARY?
C. Thompson , D. Phelan , A. Jaramillo , C. Ceriotti , W. Chapman and T. Mohanakumar . Barnes-Jewish Hospital HLA Laboratory ; Departments of Surgery and St. Louis MO, Washington University School of Medicine, Pathology .

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Sensitive crossmatch (XM) methods using flow cytometry and /or ELISA are predictive of graft outcome in high risk (HR) patients. To evaluate the sensitivity of our methods, we retrospectively analyzed ELISA and microlymphocytotoxicity (CDC) HLA antibody screens, and correlation with graft survival (1,3,and 5 years) in HR living donor renal transplant patients. Since 2000, new patients (1638) were screened by ELISA and CDC. Concordancy between methods was 82%. These two tests demonstrated significant differences (p < 0.00001). Of the 18% discordant results, 14% showed only CDC reactivity, and 4% only ELISA reactivity. ELISA is not a more sensitive assay compared to our CDC. To determine the predictive value of the CDC, we analyzed 10 years of graft outcome in HR populations. Of 380 living donor transplants performed between 1993 and 2002, 59 were HR. Patients were divided into 3 groups: child to mother, husband to wife, and living donor HLA non-identical retransplants.
CDC T and B cell XM and anti-HLA screening were performed using three wash Amos (TWA) and antiglobulin augmented (AHG) techniques. All XM were T cell negative. Positive B cell XM were observed in 7/59 (12%). 6/7 reduced with DTT indicative of IgM; 3 have function >5 yrs, 3 > 3 yrs, and 1 > 1 yr. Of 59 HR transplants, 7 had nonfunction: 2 technical failure, 2 reoccurrence of disease, 2 chronic rejection, and 1 accelerated vascular rejection. Retransplants demonstrated 100% graft survival, child to mother 93%, and husband to wife 90%. We conclude that AHG XM are sensitive enough to predict successful graft function in HR donor recipient pairs. Each center must evaluate their own test methods and correlate with graft function to formulate testing strategy encompassing the level of sensitivity and specificity for transplant testing.