IMMUNOHISTOCHEMICAL DEMONSTRATION OF THE CALCIUM-BINDING PROTEINS MRP8 AND MRP14 AND THEIR HETERODIMER (27E10 ANTIGEN) IN CROHNS-DISEASE

Monospecific antibodies against the calcium-binding proteins MRP8 and MRP14 and their heterodimer MRP8/14 (epitope 27E10) were used to inves tigate immunohistochemically the distribution of these proteins in rou tinely processed small and large bowel tissues from patients with Croh n's disease. MRP8, MRP14, and complex MRP8/14 were demonstrated in mos t granulocytes and macrophages in active Crohn's disease. Additionally , a strong complex MRP8/14 immunoreactivity was present in epithelial cells of the terminal ileum adjacent to ulcerative and fissuring lesio ns, whereas epithelial cells in large bowel tissues were consistently negative. Our results morphologically confirm the clinical finding of increased MRP8/14 serum levels in patients with active Crohn's disease ; there is evidence that the serum MRP8/14 increase is caused by activ e secretion from granulocytes, monocytes, and epithelial cells. Copyri ght (C) 1995 by W.B. Saunders Company