Fig. 1

Silicosis does not aggravate collagen-induced arthritis. a BAL cells from mice six weeks after booster immunization with collagen type II were isolated and phenotyped by flow cytometry for macrophages (CD45⁺IAq⁺GR-1⁻CD11c⁺) and granulocytes (CD45⁺IAq⁻GR-1⁺CD11c⁻). Boxes show medians and quartiles, p-values were calculated by Mann–Whitney U-test. n = 14. b Neither the arthritis incidence (left panel) nor the macroscopic arthritis score (right panel) differ between silica-treated and control mice. p-values were calculated by Fisher Test (incidence) and Mann–Whitney U-Test (macroscopic score) for each time point. c Histological scores for knee joints and paws do not differ between silica-treated and control mice. Boxes show median and quartiles, each dot represents one mouse. P-values were calculated by Mann–Whitney U-Test. d Examples for the H&E staining of thin-sections from femorotibial joints in control mice without immunization with collagen type II (upper left panel), silica-treated mice immunized with collagen type II (upper right panel) and PBS-treated mice immunized with collagen type II (lower panels) showing a high (lower right panel) or a low (lower left panel) histological score are shown. Asterisks indicate inflammatory infiltrates. Arrowheads point at sites of cartilage or bone destruction