TNFRSF1A and rheumatoid arthritis: We investigated the relationship between polymorphisms in the tumour necrosis factor receptor I (TNF-RI) and II (TNF-RII) genes and levels of sTNFRs in two groups of Caucasian RA patients: one with early (disease duration ≤2 years; n = 103) and one with established disease (disease duration ≥5 years; n = 151).