A recent study found that GAD65-specific immunotherapy had a significant effect on C-peptide retention in individuals with recent-onset type 1 diabetes who had the DR3-DQ2 haplotype, suggesting that antigen-specific immunotherapy may be most effective when targeting a specific HLA haplotype/allele linked to the tolerising antigen [31]. The gene discussed is GAD2; the disease is type 1 diabetes mellitus.