HLA-DRB1 and rheumatoid arthritis: We have replicated the following characteristics of anti-CarP antibodies: they were specific of RA, but less sensitive than the anti-CCP antibodies and less correlated with them than RF; in addition, the anti-CarP antibodies were not associated with the RA risk factors, the HLA-DRB1 and PTPN22 risk alleles or with smoking; on the contrary, they were associated with the presence of erosions with independence of the ACPA status.