P4HB and type 1 diabetes mellitus: ablation of the thioredoxin activity prevents the refolding of denatured and reduced proinsulinincreased carbonylated PDIA1/P4Hb in islets before the onset of hyperglycemiaautoantibodies against PDIA1/P4Hb and carbonylated PDIA1/P4Hb in NOD and T1D serumautoreactive T cells against carbonylated PDIA1/P4Hb peptide in T1D patientsincreased PDIA1/P4Hb level in NOD and T1D plasma