T-cell proliferative responses in patients with juvenile idiopathic arthritis (JIA) and healthy controls. Proliferative responses are presented as interquartile range for each group of data, with horizontal lines showing the median. The aggrecan and fibrillin peptides induced significant differences in responses of peripheral blood mononuclear cells (PBMC) from patients with JIA and healthy controls and are indicated as follows: **p = 0.005, *p = 0.015. The matrix metalloproteinase (MMP)-3 peptide induced proliferative responses in PBMC of patients with JIA as well as in PBMC of controls. Transparent boxes: JIA; gray boxes: healthy controls.