Concerning whether smoker had more MPO releasing into SF and whether smoker shown high carbamylation degree, unfortunately, in the tested RA samples, only 1 smoker, 2 previous smoker (one year before) and 17 non-smoker were collected, it was thus hardly to investigate associations between smoking, MPO releasing, and carbamylation degree in our current studies (Supplementary Figures S3, S4). The gene discussed is MPO; the disease is rheumatoid arthritis.