Laura Wozniak¹, Robert Venick^1,2, Yvonne Esmailian², Vilayphone Hwang², Susan Ponthieux², Sue McDiarmid^1,2, Elaine Reed³, Ronald Busuttil², Douglas Farmer²

¹Department of Pediatric Gastroenterology, UCLA, Los Angeles, CA, United States; ²Department of Surgery, UCLA, Los Angeles, CA, United States; ³Department of Pathology, UCLA, Los Angeles, CA, United States

Background: The role of panel reactive antibodies (PRAs), donor specific antibodies (DSAs), and B and T cell crossmatches (BXMs/TXMs) are largely unknown in intestinal transplantation (ITx). Recent evidence indicates their importance both before and after ITx. The aim of this study was to assess the impact of positive PRA, DSA, BXM, and TXM on ITx outcomes.

Methods: An IRB-approved, retrospective review was performed using a prospectively maintained database of all ITx recipients between 2000 and 2010. During this period, 81 patients received 94 ITxs, 71 of which were liver-inclusive. Median follow-up time was 34.5 months. Pre-ITx PRA screening was positive if >20%. BXM and TXM were routinely performed perioperatively. DSA was tested post-ITx if clinical suspicion existed. Univariate logistic regression was used to determine predictors of acute rejection (AR), chronic rejection (CR), graft loss, and patient death. Odds ratios (ORs) and 95% confidence intervals (CIs) are reported. Mean graft and patient survival in each group were compared using t tests.

Results: There were 11 +PRAs, 8 +DSAs, 8 +BXMs, and 5 +TXMs that occurred in 18 different ITxs, 8 of which were re-transplants. All patients with +TXM experienced AR. Mean number of AR episodes was greater in patients with +TXM (1.4±0.5 vs. 0.9±1, p=0.27). +BXM was a predictor of CR (OR 8.6, 95% CI 1.2-61.5, p=0.03). Predictors of graft loss included +PRA (OR 5.1, 95% CI 1.4-19, p=0.02) and +TXM (OR 6.3, 95% CI 0.97-40.8, p=0.05). Predictors of patient death included +DSA (OR 5.4, 95% CI 1.1-25.3, p=0.03) and +PRA (OR 3.3, 95% CI 0.9-12.1, p=0.07). Mean graft survival was shorter in recipients with +PRA (12±15 vs 42±36 months, p=0.01) and +DSA (9±13 vs. 29±26 months, p=0.04). Mean patient survival was shorter in recipients with +DSA (15±15 vs. 34±25 months, p=0.04).

Discussion: This study clearly demonstrates that positive PRA, DSA, BXM, and TXM are associated with increased rates of rejection and worse graft and patient survival. This data supports the avoidance of DSA and positive BXM and TXM when possible using virtual crossmatching. Larger prospective studies are needed to confirm these findings which may be difficult in ITx due to small numbers.