In multivariate analysis, DSAs were the only factor highly associated with graft failure (P ‫؍‬ .0001; odds ratio ‫؍‬ 21.3). Anti-HLA allosensitization was higher overall in women than in men (30.8% vs 12.1%; P < .0001) and higher in women with 1 (P ‫؍‬ .008) and 2 or more pregnancies (P ‫؍‬ .0003) than in men. We conclude that the presence of anti-DPB1 DSAs is associated with graft failure in MUD hematopoietic stem cell transplantation. (Blood. 2011;118(22):5957-5964)

Detection of donor-specific anti-HLA antibodies (DSA) has been associated with graft rejection in all forms of transplantation. The mechanism by which DSA increase the risk of graft failure remains unclear. We hypothesized that complement-binding DSA are associated with engraftment failure in hematopoietic stem-cell transplantation and analyzed 122 haploidentical transplant recipients tested prospectively for DSA. Retrospective C1q testing was done on 22 allosensitized recipients. Twenty-two of 122 patients (18%) had DSA, 19 of which were females (86%). Seven patients with DSA (32%) rejected the graft. Median DSA level at transplant for patients who failed to engraft was 10,055 MFI versus 2,065 MFI for those who engrafted (p=0.007). Nine patients with DSA were C1q positive in the initial samples with median DSA level 15,279 MFI (range 1,554-28,615), compared with 7 C1q negative patients with median DSA level 2,471 MFI (665-12,254) (p=0.016). Of 9 patients, who tested positive for C1q in the initial samples, 5 patients remained C1q positive at time of transplant [all with high DSA levels (median 15,279, range 6,487-22,944)] and experienced engraftment failure, while 4 patients became C1q negative pre-transplant and all engrafted the donor cells (p=0.008). In conclusion, patients with high DSA levels (> 5,000 MFI) and complement-binding antibodies (C1q positive) appear to be at much higher risk of primary graft failure. C1q should be assessed in patients with DSA prior to hematopoietic stem-cell transplantation. Reduction of DSA to non-complement binding levels might prevent engraftment failure in hematopoietic stem cell transplantation.

Summary Major ABO mismatching is not considered a contraindication to allogeneic haematopoietic stem cell transplantation (HSCT). Modern reduced-intensity conditioning and reduced-toxicity regimens cause much less myeloablation than conventional myeloablative regimens, such as cyclophosphamide with busulfan or total body irradiation, which may affect the incidence of pure red cell aplasia (PRCA). We estimated the incidence and described the natural history of PRCA in patients with major ABO-mismatched donor stem cells. Between 2007 and 2008, 161 (27% of all patients undergoing HSCT) underwent allogeneic HSCT with major ABO-mismatched stem cells and 12 (7·5%) of these patients developed PRCA. Thirty and ninety day T-cell and myeloid cell chimerism and neutrophil and platelet engraftment did not differ between patients who developed PRCA and those who did not. The only risk factor associated with PRCA was the use of a fludarabine/busulfan conditioning regimen. All patients with PRCA needed red cell transfusion for several months after HSCT resulting in significant iron overload. Pure red cell aplasia resolved spontaneously in the majority (seven patients) but only resolved after stopping tacrolimus in three patients. Hence, after major ABO-mismatched HSCT, the incidence of PRCA was 7·5% and it resolved spontaneously or after withdrawal of immunosuppression in the majority of patients.

The leprosy agents vary in geographic distribution. Finding M lepromatosis in Brazil and Myanmar suggests wide existence of this newly discovered species. The leprosy manifestations likely vary with the etiologic agents.

Background