Aim: To assess the presence of anti-HLA antibodies in intestinal transplant candidates and transplanted patients and their relationship with the developing of allograft rejection.

Patients and methods: From January 2012 to January 2013, seventeen candidates and thirty transplanted patients have been evaluated for the presence of anti-HLA antibodies by LUMINEX®. Transplanted patients included seventeen multivisceral grafts, one modified-multivisceral, five combined liver-small bowel transplant and five isolated intestinal transplant. Seven of them were retransplanted patients. In those with positive determination of anti-HLA antibodies, LUMINEX HLA SAB® to determinate donor specific antibodies (DSA) and histological examination with C4d staining was performed in order to rule out the presence of rejection.

Results: 15/17 candidateswere negative for anti-HLA antibodies class I and II. The two patients with positive anti-HLA antibodies were candidates for a third graft. 24/30 transplanted patients were negative for anti-HLA class I and II. 5/6 positive patients were retransplanted (3 with a third graft), four of them were positive for DSA against previous donor (two class I and two class II) without any sign of rejection. One patient (third graft) had positive cross-match test and positive anti-HLA antibody class I (484159 SFI) and II (506416 SFI) with positive DSA against his three donors. There was no signs of rejection and he normalized antibodies levels after desensitizing treatment. The only non-retransplanted patient with positive anti-HLA antibodies class II (465659 SFI) and strongly positive DSA, developed an ulcerative ileitis with C4d positive staining in histological samples. After treatment (Rituximab + IVIG) clinical, histological and immunological normalization was obtained.

Conclusions: Anti-HLA sensitization is unusual in candidates and transplant patients without previous grafts. However, it is a frequent finding in retransplanted patients. We don't know the role of these antibodies in previous lost grafts due to acute or chronic rejection. Only in one patient of our series, an apparent positive relationship can be made between sensitization and rejection.