Another study by Alzolibani and colleagues, in 2016, alopecia areata patients expressed several TLRs (namely TLRs 3, 7, 8, and 9), though TLR4 expression was not significantly different from that of the control group [34]; this study paved the way for further investigation about the role of TLR4 in autoimmune diseases of the skin. This evidence concerns the gene TLR4 and alopecia areata.