SPN and rheumatoid arthritis: SIN reduces RA disease activity and DAS28 scores by suppressing pro-inflammatory cytokines (e.g., IL-6, TNF-α, IL-1β) and modulates immune cells, including synovial macrophages (CD11b+F4/80+CD64+) and splenic/draining lymph node macrophages (CD11b+Ly6C+CD43+), while lowering CD14+CD16+ monocytes in RA patients.