To further assess the contribution of ILCs to arthritis development, we x-irradiated Thy1.1+Rag2−/− mice, reconstituted them with BM cells from Thy1.1+Rag2−/− mice and Thy1.2+Csf2−/− SKG mice at a 1:1 ratio, and treated the mice 6 weeks later with a single injection of 20 mg mannan and subsequently with 500 μg anti-Thy1.1 mAb once a week. This evidence concerns the gene CSF2 and arthritic joint disease.