ICAM1 and arthritic joint disease: In conclusion, recruitment of leukocytes into the joints and the ensuing arthritis in the K/BxN STA model seem to be dependent on the expression of LFA-1 on leukocytes, especially neutrophils, and the binding to its ligands, ICAM-1, ICAM-2, and JAM-A, expressed on the activated vascular endothelium (Figure 2).