Although the HLA-DRB5 genotype was not significantly more prevalent in ACPA+ RA (49/141, 34.8%) compared with ACPA- RA (15/48, 31.3%) and HCs (10/34,29.4%) (Supplementary Fig. 8a), evidence of disease activity, including DAS28, CRP, and IgM were significantly higher in ACPA+ RA with HLA-DRB5 genotype, whilst this was not observed in ACPA- RA (Supplementary Fig. 8b). This evidence concerns the gene HLA-DRB5 and rheumatoid arthritis.