RELEVANCE OF HLA MATCHING AND HLA ANTIBODIES TO REJECTION AND GRAFT LOSS IN LIVER RECIPIENTS

6.4
TITLE: RELEVANCE OF HLA MATCHING AND HLA ANTIBODIES TO REJECTION AND GRAFT LOSS IN LIVER RECIPIENTS

Ronald H. Kerman,¹ Stephen M. Katz,¹ Jacqueline Lappin,¹ Claire F. Ozaki,² Jackie Abrams,² Barry D. Kahan,¹ Patrick R. Wood.²

¹Surgery, University of Texas Medical School – Houston, Houston, Texas; ²Surgery, St. Luke’s Episcopal Hospital, Houston, Texas

The role of donor–recipient (recip) HLA matching for liver transplant (Tx) remains controversial. In our study no benefit was seen in HLA matching . Also, it has been assumed that liver Tx were less susceptible to damage from IgG HLA antibodies (Abs). This was based on data that identified Abs utilizing membrane assays, which may measure non–HLA receptors. We tested for Flow–PRA IgG HLA Abs to determine whether they impact graft rejection (rejxn) or loss. We Flow PRA tested the preTx sera of 257 liver recips. Sixty–four percent (164/257) of the recips displayed a preTx class I Ab Flow PRA of 0% and a 23% incidence of rejxn during the first post Tx year. Recips with 3–10%, 11–50% or ≥51% class I Flow PRAs had comparable incidences of rejxn of 20%, 24% and 35%, respectively. The one, two and three year graft survivals of these various PRA groups were comparable. Similarly, 68% (175/257) of the recips displayed a preTx class II Flow PRA of 0% and a 22% incidence of rejxn. Recips with 11–50% or ≥51% Flow PRAs experienced non–significantly different 34% and 29% incidences of rejxn respectively and graft survivals at one, two and three years were comparable. Since the recips with ≥51% Flow PRA for either class I or class II Abs were near statistical significance we evaluated the rejxn frequency and graft survival for the 37 patients presenting with flow PRAs for both class I and class II ≥51%. There were no graft survival differences at one, two and three years for recips with high or low Flow PRAs. However, the rejxn frequency of 38% (14/37) vs. 23% (50/220) for class I and II Flow PRAs ≥51% vs all others was significantly different p < 0.05. Finally, if patients with ≥51% class I and class II Flow PRA presented with a positive flow cytometry crossmatch (FCXM) their one year graft survival was 55% vs 100%, p < 0.01 for double high patients but with a negative FCXM. Therefore, in our study 14% (37/257) of the patients presented with high (≥51%) Flow PRA class I and II HLA Abs and were at risk for rejxn. If they also displayed a positive FCXM (suggesting donor specific HLA reactivity) they were at high risk for graft loss.