However, certain combinations of HLAs have been correlated to a higher risk of appearance of autoimmune disorders, such as T1D [173,174], rheumatoid arthritis [174], coeliac disease [175], etc. According to this knowledge, the cell replacement-based approach of T1D treatment must face the immune barrier issue of whether a patient will receive SC-derived-β cells as either auto- or allograft. The gene discussed is HLA-S; the disease is type 1 diabetes mellitus.