The prognostic relevance of donor-specific antibodies in facial transplantation - A retrospective cohort study.

Background: Little is known about the prognostic relevance of donor-specific antibodies (DSAs) and C4d tissue deposition for acute and chronic rejection in facial vascularized composite allotransplantation.

Methods: We conducted a retrospective analysis of nine face transplant patients. Outcome measures, such as DSA positivity, were determined by the local tissue typing laboratory, whereas C4d deposition was assessed by immunostaining. Acute rejection events, occurrence of chronic rejection, and transplant-related outcomes were collected.

Results: Five (5/9) patients developed de novo DSAs. Among the 56 time points when rejection grade, DSA, and C4d levels were measured concurrently, 25 (44.6%) had only one positive parameter (DSA or C4d), 23 (41.1%) had two negative values, and 8 (14.3%) had both parameters positive. A trend was observed where acute rejection grades were higher at time points with both DSA positivity and C4d deposition compared with time points where both parameters were negative. Chronic rejection was observed in four patients, two of whom developed DSAs and two who did not. Among the five patients who developed de novo DSAs, graft loss occurred in one patient. The remaining four patients with de novo DSAs retained their allografts [mean follow-up: 118 (63-162) months].

Conclusion: We identified a potential association between DSAs and grade of acute cellular rejection. Chronic rejection was observed in four patients, with no clear association with DSA status. Only one out of five patients who developed DSAs underwent graft loss. Further studies need to explore the mechanistic role of DSAs in the setting of VCA rejection.