TLR4 and type 1 diabetes mellitus: The underlying mechanisms of BCG vaccination on T1DM may be: 1) BCG vaccination up-regulates Myc, activates nearly 24 Myc target genes under four metabolic pathways, and finally improves glucose metabolism in T1DM patients (94); 2) BCG vaccination induces an increase in the methylation levels of H3K4me3 (Histone 3 Lysine 4) and H3K36me3 (Histone 3 Lysine 36me2), which activates cytokines (TNF, IL-6, and TLR4) related to BCG therapy in T1DM patients (95).