Expression of the High-Affinity IgG Receptor FcRI (CD64) in Patients With Inflammatory Bowel Disease: A New Biomarker for Gastroenterologic Diagnostics

Abstract

We sought to determine the quantitative expression of the high-affinity Fc receptor (CD64) on polymorphonuclear neutrophils (PMNs) in inflammatory and functional conditions of the intestine and investigated its correlation with clinical and biological parameters of inflammation. The quantitative expression of CD64 was determined by fluorescence-activated cell sorting analysis in patients with active or inactive inflammatory bowel disease (IBD, n=76), infectious enterocolitis, lactose and/or fructose intolerance, and healthy subjects. The quantitative expression of CD64 in patients with active IBD (3,398+/-3,589 molecules per PMN, n=27) was significantly higher than in healthy subjects (607+/-265, n=28, P<0.001) or in patients with lactose/fructose intolerance (531+/-150, n=32, P<0.001). The expression of CD64 correlated significantly with C-reactive protein (CRP, 0.65, P<0.0001), Crohn's disease activity index (CDAI, 0.53, P<0.0001), and colitis activity index (CAI, 0.63, P<0.0001) in patients with IBD. With a cutoff point of 800, CD64 had a sensitivity of 88% and a specificity of 93% in discriminating between lactose/fructose intolerance and active IBD. The quantitative expression of CD64 in patients with infectious enterocolitis (19,190+/-8,920, n=22) was significantly higher than in patients with active IBD (P<0.001). With a cutoff point of 10,000, CD64 showed a sensitivity of 96% and a specificity of 97% in discriminating between infectious enterocolitis and active IBD. CD64 could serve as a valuable tool to discriminate between IBD, infectious enterocolitis, and functional intestinal disorders.