HLA-DRB1 and type 1 diabetes mellitus: Thus, in sharp contrast to DRB1*09:01 (which also has been reported to be associated with predisposition to RA [20,21], SLE [21], type 1 diabetes [22], and myasthenia gravis [23]), DRB1*13:02 or other allele(s) in strong LD appears to have a protective effect against multiple autoimmune rheumatic diseases.