Arthritic and non-arthritic synovial fluids modulate IL10 and IL1RA gene expression in differentially activated primary human monocytes

A lower expression of IL10 may be regarded as a response to less inflammatory conditions since IL10 expression is higher in response to IFN-γ/TNF-α stimulation, probably as a feedback mechanism. Therefore, the lower expression of IL10 and the higher expression of IL1RA in Mo exposed to arthritic than to non-arthritic SF suggest that arthritic SF is mainly reducing the inflammatory responses in Mo. This may mimic the response of monocytes/macrophages recruited to the joint, where feedback mechanisms counteract pro-inflammatory processes.