Positions 11 and 26 have been associated previously with seropositive autoimmune disease, such as systemic lupus erythematosus 32, which suggests that these positions may determine properties of the HLA–DRB1 peptide‐binding groove, allowing it to preferentially bind autoantigenic peptides (Figure 3). The gene discussed is HLA-DRB1; the disease is systemic lupus erythematosus.