Long-term anti-CD154 dosing in nephritic mice is required to maintain survival and inhibit mediators of renal fibrosis

The CD154/CD40 pathway is required for the development and progression of disease in a variety of autoimmune model systems. We have demonstrated previously that long-term anti-CD154 treatment of nephritic (SWRxNZB)F-1 mice prolonged survival and preserved kidney function. Herein we ask if long-term treatment is required and further characterize the protective effect on renal pathology by examining alpha -smooth muscle actin, collagen and TGF-beta1 expression in renal tissue. The effects of anti-CD154 on brain and heart inflammation are also examined. Three dosing strategies of anti-CD154 mAb were compared in SNF1 mice that exhibited moderate or severe nephritis: (1) weekly for 6 weeks; (2) monthly; (3) weekly for 6-12 weeks followed by monthly dosing. Proteinuria, serum anti-DNA, anti-CD154 pharmacokinetics and serum soluble CD154 analyses were performed. Anti-CD154 treatment of moderate disease increased survival across all regimens, although weekly followed by monthly maintenance dosing proved most efficacious. This regime also inhibited renal alpha -smooth muscle actin and collagen deposition. Only the most aggressive anti-CD154 treatment protocol increased survival in severely nephritic mice. Long-term anti-CD154 treatment significantly inhibits key mediators of kidney fibrosis and is required to maximize survival and renal function. Potential reasons for differential therapeutic efficacy in moderately vs severely nephritic mice are discussed.