CD4 and rheumatoid arthritis: While the interactions of HLA-DRB5+ DC and HLA-DRB5- DC with S100A8hi Cytotoxic CD4 T or NK/CD4 T were similar, HLA-DRB5- pDC, which were more abundant in ACPA- RA, exhibited stronger interactions with cytotoxic T subsets than HLA-DRB5+ pDC (Fig. 10a).