Expression of Carcinoembryonic Antigen–Related Cell Adhesion Molecule 1 in Acute Rejection of Human Renal Allografts

Abstract

Background Carcinoembryonic antigen–related cell adhesion molecule 1 (CEACAM1) is expressed on various cell types and mediates homophilic cell adhesion. CEACAM1 plays an important role in cell morphogenesis and angiogenesis. Furthermore, CEACAM1 regulates adhesive activity of immune-competent cells, suggesting an additional role in inflammatory processes. Methods Therefore, in the present study the expression of CEACAM1 was analysed retrospectively in renal biopsies from kidney transplant recipients (stable graft [Ctr; n = 18], acute vascular rejection [AVR; n = 14], acute tubulointerstitial rejection [AIR; n = 9], and combined vascular and interstitial rejection [AVIR; n = 7]). Expression patterns of CEACAM1 were determined using immunohistochemistry and quantitative morphometry. Results All biopsy specimens from patients with stable grafts showed low CEACAM1 levels, suggesting a constitutive expression in renal transplants. In patients with acute rejection, CEACAM1 was markedly up-regulated. AVR revealed the highest tubular CEACAM1 levels (4.9 ± 0.5% [AVR] vs 2.2 ± 0.3% [Ctr] of tubular area; P < .05), whereas interstitial rejections showed the highest glomerular expressions (4.5 ± 0.5% [AIR] vs 0.9 ± 0.1% [Ctr] of glomerular area; P < .05). Conclusions An up-regulated expression of CEACAM1 in tubular and/or glomerular cells is an indicator of acute inflammatory processes in biopsy specimens from patients with acute renal allograft rejections and, therefore, might be used as a new clinical marker.