The elevated production of IL-6 as well as MMP3 from ERA patients at baseline as compared to adult axial SpA may indicate that the monocytes from ERA patients are more activated and this could be related to higher disease activity as reflected by presence of more active peripheral arthritis and enthesitis in ERA patients as compared to adult axial SpA. This evidence concerns the gene MMP3 and enthesitis-related juvenile idiopathic arthritis.