HLA-G and type 1 diabetes mellitus: The discovery that DC-10 are present in vivo (7, 14), modulate T-cell responses, induce Tr1 cells in vitro in a HLA-G-dependent manner, and are associated with tolerance (15) prompted us to postulate that DC-10 represent an important subset of naturally occurring HLA-G-expressing DCs involved in promoting tolerance in T1D than can be used as biomarker for staging the disease in conjunction with classical prognostic factors.