In addition, several studies have found a connection between HLA class II molecules and immune-mediated disorders, such as susceptibility loci in HLA-DRB1 for sarcoidosis [41] and pemphigus [42] and susceptibility loci in HLA-DQA1 for achalasia [43] and celiac diseases [44]. This evidence concerns the gene HLA-DRB1 and Achalasia.