Effectiveness of Bortezomib in a Patient with Acute Rejection Associated with an Elevation of Donor-Specific HLA Antibodies after Small-Bowel Transplantation: Case Report

Background A significant association between donor-specific antibody (DSA) and graft rejection has recently been documented. However, confirmed strategy has not been established for DSA-associated rejection after intestinal transplantation (ITx). Case Report A 20-year-old male patient with chronic intestinal obstruction caused by hypoganglionosis of the entire intestine underwent cadaveric donor ITx with grafting performed on 232 cm of the small intestine, cecum, and a part of the ascending colon. On post-operative day (POD) 14, a histological evaluation showed an acute rejection of indeterminate grade. The patient had severe acute rejection on POD 16, which prompted us to administer bolus steroids and polyclonal anti-thymocyte antibody, along with baseline maintenance immunosuppression. The histopathological findings of the graft indicated typical acute cellular rejection, although C4d was positive. We then detected donor-specific HLA antibody. The patient initially responded well to the therapy and showed decreased histological rejection signs. However, the refractory low-grade rejection persisted in the graft. During this period, the patient showed increased levels of DSA, and we speculated that the persistent rejection was associated with DSA; thus, bortezomib was administered at this stage as a salvage therapy. This rejection was thereafter successfully controlled without severe adverse effect. Twenty-three months after ITx, the patient is currently alive with complete enteral autonomy. Conclusions A case of acute graft rejection followed by a marked elevation of DSA is presented. In this particular case, a modified treatment protocol using bortezomib in addition to the typical immunosuppressive agents was effective.