Cyclosporin A reduces expression of adhesion molecules in the kidney of rats with chronic serum sickness.

Treatment with cyclosporin A (CsA) improves proteinuria and reduces renal cellular infiltration in chronic serum sickness (CSS). We examined if these effects were associated with a reduced renal expression of CD54 and its ligands, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and MHC class II molecules. We studied two groups of rats in which CSS was induced by daily injections of ovalbumin (OVA): a group treated with CsA (OVA.CsA group, n = 11) and a group that received no treatment (OVA.CSS group, n = 11). An additional group of five rats (control group) received only phosphate buffer. Immunostaining techniques were used to follow CSS and to study the expression of CD54, CD18, CD11b/c, IFN-gamma, TNF-alpha and MHC class molecules. Proteinuria (mg/24 h) was reduced from 248.2 +/- 73.1 (OVA.CCS group) to 14.5 +/- 13.1 with CsA treatment (P < 0.0001). The renal expression of CD54 and its ligands (CD18 and CD11b/c) was reduced by 50% to 75%. Correspondingly, there was a 60% to 85% reduction in the number of infiltrating leucocytes. The number of cells expressing TNF-alpha, IFN-gamma and MHC II molecules was also reduced. CsA reduces expression of CD54 and its ligands. This effect is associated with a reduction of cellular infiltration, IFN-gamma, TNF-alpha-producing cells and with MHC II expression in the kidney. These findings suggest that expression of adhesion molecules plays a critical role in CSS and underline the importance of cellular immunity in this experimental model.