T-cell, B-cell, macrophage, and granulocyte expression in the synovium of mice with collagen-induced arthritis, after 7 days of IFN-β therapy, detected by immunohistochemistry. Sections were scored for CD3 and CD22 as described in Materials and methods. Macrophages and granulocytes were evaluated by morphology. (a) CD3 expression. (b) CD22 expression. (c) Macrophage expression. (d) Granulocyte expression. No significant differences between treated animals and controls were observed for CD3 and CD22 expression (P = 0.4 for both). Statistically significant differences were observed for macrophage and granulocyte expression between IFN-β-treated mice and saline-treated mice (P = 0.04 and 0.009, respectively). *Statistically significant difference.