IL18 and rheumatoid arthritis: For greater demonstrativeness, the fold change, expressed as log2 in tested cytokine levels in sera of female patients with RA as opposed to healthy females, is presented in Fig. 1 (21 fold for IL-6; 6.1 fold for IL-17A; 2.5 fold for IL-23; 2.3 fold for IL-18; 1.94 fold for TNF-α; 1.7 fold for IL12p40).