LAUSR

We read with interest the study by Pouliquen et al for the GRAGIL network (1). This seeks to address the important question of the role of donor-directed HLA antibodies (DSAs) after pancreatic islet transplantation by examining samples from multiple centers. This approach has enabled the inclusion of a relatively large number of recipients but with a limited frequency of DSA assessment—annually posttransplantation. This may explain, at least in part, the apparently discrepant findings between this study and an earlier report from our center (2). Additionally, HLA typing of recipients and donors was not always complete and it is not clear whether HLA-DP is considered. Also, the multiplicity of HLA alleles within certain allele groups, for instance, HLA-DR4/(-DQ7/-DQ8), makes ascription of associated alleles imprecise and would potentially introduce some inaccuracy into later calculations.