CD4 and rheumatoid arthritis: While the synovial tissue CD4 T cell cytokine response comparison between ACPA− and ACPA+ RA is better served by the PCA analysis of Figure 5D, adding additional variables in the form of peripheral blood CD4 T cell responses and performing new PCA analysis shows the similarities of ACPA+ and ACPA− RA patient peripheral blood response and the separately grouped, more proinflammatory synovial responses influenced by increased expression of TNF-α, IFN-γ, IL-17A, IL-22 and GM-CSF but not IL-2 (Figure S2).