A review on (1) structure and immunopharmacol. characteristics of anti-TNF antibody drugs and TNF receptor-IgG Fc fusion proteins, (2) clin. effects of infliximab, etanercept, and adalimumab in the treatment of rheumatoid arthritis (RA), (3) optimization of therapeutic efficacy of TNF inhibitors on RA, (4) safety of TNF inhibitors, and (5) clin. efficacy and adverse effects of infliximab in Japan.