TNF and psoriatic arthritis: M: male; F: female; AS: ankylosing spondylitis; RA: rheumatoid arthritis; PSA: psoriatic arthritis; TNFi: tumor necrosis factor inhibitor; anti-dsDNA: anti-double-stranded DNA antibodies; ANA: antinuclear antibodies; ENA: extractable nuclear antigen; AMA-M2: anti-mitochondrial antibody M2; anti-RNP: anti-ribonucleoprotein antibodies; -: negative; +: positive