The analysis of both disease incidence and the T-cell subsets involved indicates that, while the behavior of WT mice in terms of immune response to chicken type II collagen is similar to that repeatedly published by other authors, emphasizing the role of Th17 cells, IL4-producing cells and Treg cells in the development of RA [25, 46], the mice deficient in EphB2 or EphB3 seem to exhibit altered functional properties that affect their reactivity to type II collagen or other immune stimuli, or their migratory capacities. Here, IL4 is linked to rheumatoid arthritis.