THE MYELOIC RELATED PROTEIN MRP8 14 (27E10 ANTIGEN) - USEFULNESS AS APOTENTIAL MARKER FOR DISEASE-ACTIVITY IN ULCERATIVE-COLITIS AND PUTATIVE BIOLOGICAL FUNCTION/

MRP8, MRP14 and their heterodimer MRP8/14 (27E10 antigen) are myeloic related proteins which have been shown to have a major role in inflamm atory and immunological responses. In the present study monospecific a ntibodies against MRPs were used to investigate immunohistochemically the distribution of these proteins in routinely processed bowel tissue s from 23 patients with ulcerative colitis (UC). MRP8, MRP14 and their heterocomplex MRP8/14 were demonstrated in the majority of granulocyt es and macrophages in tissues of patients with active UC. Furthermore by employing the ELISA technique we measured MRP8/14 serum levels in 6 2 patients with UC and the results were compared with those for health y controls. Disease activities were determined;by established clinical activity indices. Serum MRP8/14 concentrations were significantly (P < 0.0001) increased in patients with active ulcerative colitis. No enh ancement of serum levels were found for MRP14 and MRP8 alone, respecti vely. The follow-up of individual patients with initially active disea se showed a decrease of MRP8/14 serum levels in parallel with clinical improvement following the start of therapy. It is thus concluded that MRP8/14 accurately reflects the degree of disease activity in UC. Fur ther, possible biological function of MRPs seems to be associated with the heterodimeric form (27E10 antigen) rather than with individual pr oteins. Our morphological results confirm the finding of enhanced MRP8 /14 serum levels in patients with active UC.