Cytomegalovirus accelerates chronic allograft nephropathy in a rat renal transplant model with associated provocative chemokine profiles

Background. Studies have shown that rat cytornegalovirus (RCMV) infection accelerates transplant vascular sclerosis (TVS) in rat heart and small bowel allotransplants. In these models, RCMV-accelerated TVS results from increased graft infiltration of inflammatory cells through up-regulation of chemokine expression. The aim of this study was to determine if RCMV infection accelerates renal transplant chronic allograft nephropathy (CAN), and the role of chemokines in this process. Methods. F344 kidneys were transplanted into Lewis recipients with and without RCMV infection. To monitor CAN, serum creatinine (Cr) levels were measured starting at 4 weeks posttransplantation. At 7 and 21 days, and at terminal rejection, grafts were examined for histologic changes, inflammatory cell infiltrates, viral load, and chemokine expression profiles. Results. By week 8, serum Cr showed significant elevation (P < .01) in the RCMV-infected group vs uninfected group, and remained significantly elevated through the end of the study. RCMV+ renal allografts had significant inflammatory cell infiltration and increased CAN at postoperative day (POD) 28. The CC chemokines RANTES, MCP-1, and MIP-1 alpha, and the CXC chemokine IP-10 were up-regulated in RCMV-infected vs uninfected allografts. IP-10 was significantly up-regulated early in the process, whereas RANTES and MCP-1 were induced at a later time. Conclusions. RCMV infection accelerates CAN, with associated graft inflammatory infiltrates, which is paralleled by an increase in expression of CC and CXC chemokines. Our findings suggest that the early induction of IP-10 in the infected allografts promotes alterations in T-cell and monocyte migration to the graft, which initiates accelerated inflammatory and fibrotic changes associated with CAN.