In detail, around 38% and 12.5% of healthy blood donors resulted to respectively carry HLA-DQB1*02 and/or HLA-DQB1*03:02 alleles, which encode the β chain of class II MHC heterodimers (respectively, DQ2 and DQ8) known to represent the necessary (but not sufficient) immune-genetic background to develop CD. Here, HLA-C is linked to Cowden disease.