At present, reduction in CD68-positive macrophages of the sublining (sl) represents the most accepted and validated response biomarker in longitudinal studies in RA, applicable to several types of drugs, while the reduction in CD3+/CD68+sl cells applies to tumour necrosis factor-alpha inhibitors (TNFis) treatment in PsA (13, 15). This evidence concerns the gene CD68 and rheumatoid arthritis.