Figure 4.

Change in disease activity in relation to change in P. copri abundance. At follow‐up, 3 months after treatment start, change in disease activity is associated with change in P. copri abundance in patients with positive RF (r_s = 0.344, P = 0.046, n = 34) but not patients with negative RF (r_s = −0.17, P = 0.541, n = 16). The majority of patients with positive RF who experienced a positive response to their immunosuppressive therapy also exhibited a decline in P. copri levels (lower left quartile). DAS28‐CRP, disease activity score based on 28‐joint counts; P. copri, Prevotella copri; RF, rheumatoid factor.