Sequential analysis of adhesion molecules and their ligands in rat renal allografts during the development of chronic rejection

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molec ule-1 (VCAM-1) are important in endothelial cell-leukocyte interactions. In this sequential study, the expression of ICAM-1 and VCAM-1 and their ligan ds LFA-1 and VLA-4 as well as major histocompatibility complex class II ant igens (MHC class II), and interleukin-2-receptor (IL-2R) were investigated during the development of chronic renal allograft rejection in a rat model. The time-related expression of adhesion molecules and their ligands in the graft was correlated to the chronic allograft damage index (CADI). In asso ciation with an initial short immune activation, there was a significant IC AM-1 and VCAM-1 induction in the vascular endothelium and the tubular epith elium. In the interstitium, there was infiltration of lymphocytes expressin g ligand molecules VLA-4 and LFA-1, as well as activation markers MHC class II and IL-2R. Thereafter, the expression declined together with the increa se of CADI-values. In end-stage chronic rejection, there was practically no expression of ICAM-1 and VCAM-1. In the interstitium, there were only few ligand-expressing leukocytes. In conclusion, adhesion molecules and their l igands are involved in the induction phase of the process but no longer in the later stages of chronic rejection.