CD4 and rheumatoid arthritis: When looking 2–6 weeks after dose 3, we found that the frequencies of spike-specific Th1 (CXCR3+CCR6−CCR4−), Th2 (CXCR3−CCR6−CCR4+), and Th17 (CXCR3+CCR6+CCR4+) CD4+ T cells did not differ between those on different RA drug treatments, or controls (Fig. 4a–c).