Additional file 2 of Peptidoglycan in osteoarthritis synovial tissue is associated with joint inflammation

Supplemental figure S2: Cytokine secretion by primary human synovial fibroblasts stimulated with peptidoglycan (PG), stratified by primary diagnosis. Primary human synovial fibroblasts were isolated from 4 patients with Lyme arthritis (LA), 3 with rheumatoid arthritis (RA), 8 patients with osteoarthritis (OA), 2 with joint trauma (OA and trauma combined in ?Other), passaged at least 6 times prior to stimulation. Cells were stimulated with 10 ?g/ml of S. aureus PG muramyl dipeptide (Sigma-Aldrich) or media alone (ctrl) for 24 hours. Shown are mean (+/- SD) of pro-inflammatory and anti-inflammatory/pro-fibrotic cytokines detected in cell culture supernatant by multiplex assay. Statistically significant differences between control and PG-stimulated cells were determined by paired two-tail t test (p values are indicated in figure).