CD4 and rheumatoid arthritis: However, when we compared RA with OA, we found 1085, 69, 1, and 0 differentially accessible regions in monocytes, CD4+ T cells, CD8+ T cells, and B cells, respectively (|log2 fold change | > 1, p < 0.001, FDR < 0.1), and the differentially accessible regions between cell types exhibited barely any overlap (Fig. 2a, b).