Treatment of Allosensitized Patients Receiving Allogeneic Transplantation

Donor-specific anti-HLA antibodies (DSA) are a major cause of engraftment failure in patients receiving haploidentical stem cell transplantation (HaploSCT). Effective treatments are needed for these patients who often have no other donor options and/or are in need to proceed urgently to transplantation. We studied a multimodality treatment with alternate day plasma exchange, rituximab, intravenous gamma globulin (IvIg) and an irradiated donor buffy coat for patients with DSA at two institutions. Thirty-seven patients with a median age of 51 years were treated with this desensitization protocol. Treatment outcomes were compared with a control group of HaploSCT patients without DSA (N=345). Majority of patients in the DSA group were females (83.8% vs. 37.1% in controls, p 20,000 MFI and with persistent C1q+ after desensitization had a significantly lower engraftment rate, resulted in a significantly higher non-relapse mortality (NRM) and worse overall survival (OS) than controls whereas graft outcome and survivals of patients with initial DSA <20,000 MFI and those with negative C1q after treatment were comparable with controls. In conclusion, treatment with plasma exchange, rituximab, IvIg and donor buffy coat is effective in promoting engraftment in patients with DSA up to 20,000 MFI.