HLA-DRB1 SE alleles are associated with ACPA-positive RA.41 We found a strong association of anti-cTNC5 antibodies with SE positivity, as has been described for antibodies to other citrullinated antigens, like CEP-1 and cVIM.14, 15 cTNC5 antibodies mainly associated with HLA-DRB1 subtypes DRB1*04 as described for other ACPAs.15, 39 HLA-DR13 alleles protect against ACPA-positive RA,42 and we show here that it is also protective against cTNC5-positive RA. The gene discussed is HLA-DRB1; the disease is rheumatoid arthritis.