In a more recent study from Salliot et al. [28] the use of hormone replacement therapy in women with early undifferentiated arthritis is proposed to protect against the development of criterium-defined RA in individuals carrying HLA-DRB1 SE alleles (OR 0.43, 95 % CI 0.24–0.77) by reducing the risk for the presence of ACPA. This evidence concerns the gene HLA-DRB1 and rheumatoid arthritis.