We analysed 23 functional polymorphisms in CARD8, IFNGR1, IFNGR2, IL12B, IL12RB1, IL12RB2, IL17A, IL18, JAK2, NLRP1, NLRP3, TBX21, TIRAP, TLR1 and TLR5 in a Danish cohort of 538 RA patients treated with anti-TNF and prospectively monitored for treatment effect using validated clinical scoring methods. The gene discussed is IL18; the disease is rheumatoid arthritis.