Class I and II human leukocyte antibodies in pediatric haploidentical allograft candidates: prevalence and risk factors

Donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) were associated with graft failure (GF) following haploidentical stem cell transplantation (Haplo-HSCT). The prevalence and risk factors of DSAs in pediatric candidates remain to be determined. In a prospective trial (ChiCTR-OPC-15006672), 486 children with hematological diseases were enrolled to screen for the presence of anti-HLA class I and II antibodies of immunoglobulin G type. Fifty two patients (10.7%) demonstrated positive panel-reactive antibody (PRA) for class I; 24 (4.9%), for class II; and 13 (2.7%), for both. Multivariate analysis showed diagnosis was the independent risk factor for antibodies, as acute lymphoblastic leukemia (ALL) patients (HR0.141, 95% CI: 0.037-0.538, p = 0.004) had a lower incidence of class II PRAs and DSAs against HLA-B, DQ, and DR, whereas myelodysplastic syndrome (MDS) patients had a higher incidence of PRAs for both class I and class II (HR4.790, 95% CI: 1.010-22.716, p = 0.049), and DSAs against HLA-A, B, C, DP, and DQ. Older age (>12 vs. ≤12) was associated with DSAs against HLA-DP (HR0.194, 95% CI: 0.041-0.918, p = 0.039). Our findings provided novel evidence for prevalence and risk factors for PRAs and DSAs in pediatric candidates receiving haplo-HSCT, possibly benefiting anti-HLA antibody monitoring and donor selection.