STAT4 and type 1 diabetes mellitus: We conclude that the nine loci (FCRL3, RASGRP1, SH2B3, STAT4, BACH2, UBASH3A, IL2, PTPN22, and CTLA4) associated with TPOA, which is not a T1D anti-islet autoantibody, may have general effects in adaptive immunity, in the complex interactions between antigen presenting cells and T cells leading to antibody-producing plasma B cells.