Anti-IL-6 immunotherapy reduced the loss of cartilage matrix components in CIA. Representative images of cartilage matrix component loss during collagen-induced arthritis in mice treated with control antibody (A), 1 mg/week anti-IL-6 (B) or 5 mg/week anti-IL-6 (C). Photomicrographs are 200×. Image analysis of the staining densities was conducted to quantify the matrix protein loss in photomicrographs (D). Bars represent the mean (± SEM) value of staining density based on the matrix degradation scoring system defined in Table 4. Statistical differences between the groups were determined using ANOVA (SPSS Inc, Chicago, IL).