CD4 and Arthritis: Flow cytometry analysis showed significantly increased recruitment of CD45+CD4+Ccr6+ (Th17) cells and CD45+CD4–Ccr6+ (expected as a B cell–rich fraction) cells in arthritis tissue from Uhrf1ΔCol6a1 mice in the late but not early phase of STA (Figure 5K and Supplemental Figure 4G).