Their results showed that oral probiotics lowered the pro-inflammatory cytokine IL-6 (SMD—0.708, 95% CI—1.370 to 0.047, p = 0.036), which is an indicator for joint destruction in RA, but no significant differences were found in disease activity score (DAS) and swollen joint count (SJC) between the probiotic and placebo groups. Here, IL6 is linked to rheumatoid arthritis.