#3-OR
PRE TRANSPLANT DONOR SPECIFIC ANTIBODIES ARE ASSOCIATED WITH POOR GRAFT FUNCTION AFTER ISLET CELL TRANSPLANTATION.
Patricia Campbell MBChB 1, Edmond Ryan MD 2, Anne Halpin MSc 1, Sharleen Imes MSc 2 and James Shapiro MD 2. 1 Dept of Lab. Medicine, Univ of Alberta, Edmonton, AB, Canada and 2 Clinical Islet Program, Univ of Alberta, Edmonton, AB, Canada .
At the time Islet transplantation began in Edmonton in 1999, T cell crossmatch and antibody screening was done by AHG. In 2003 we introduced flow antibody screening and crossmatching and we wanted to determine whether HLA antibodies detected by flow pre-transplant impacted the outcomes of the islet cell transplant.
Pretransplant sera were tested for HLA antibodies by FLOWPRA
and T and B cell flow crossmatches were done with frozen spleen cells. Grafts were excluded from analysis if there were no donor cells or if they had not reached 1 year of follow up.
Unlike kidney transplantation there are no biopsies to confirm rejection in islet cell transplantation. We used the 
Score1 as a marker of cell function post transplant. This is a composite score that provides a measure of islet cell function. A scores of <3 indicates very poor islet cell function.
Two year data was available for 104 grafts and is shown in the table. A positive PRA pre-transplant was associated with a low score at 1 and 2 years whereas a positive crossmatch was not. The presence of donor specific antibodies (DSA) was highly significant for a low score .
At 2 years all the patients with pre-transplant donor specific antibody have a score <3. This is true for both class I and II HLA antibodies. Although many factors contribute to islet cell loss post transplantation, this data strongly suggests that pre transplant HLA antibodies play a role in graft loss.
1.Ryan et al Diabetes Care 28: 2 pgs 343-47,2005 scorescore<3 n=22score
3 n=82p value Pos PRA 15 13 Neg PRA 7 69 4.6E-07 DSA 8 0 No DSA 14 82 1.24E-06