Blood test in Rheumatoid Arthritis (RA) patients with good response to anti-Tumor Necrosis Factor (anti-TNF) and in patients with moderate or non-response will be done in the month following the evaluation of clinical response to therapy. Isolation of mononuclear cells and purification of monocyte by negative selection. Cell culture of monocyte in presence or not of anti-TNF for 24 hours and analyze of CD36 (cluster of differentiation antigen 36) expression (principal outcome). For secondary outcomes analyze monocyte phenotype, NRF2 nuclear translocation, and clinical data of patients.