TLR4 and diabetes mellitus: In addition, a recent study performed by Simon et al. found that NOD TLR4−/− animals had an increased risk of progression to diabetes along with higher abundance of Bacteroidetes and lower Firmicutes in the large intestine before the onset of T1D when compared to NOD TLR4+/+ mice, indicating that TLR4 expression status determined early alterations of gut microbial composition (111).