Prevalence and Clinical Relevance of Anti-FcεRI Autoantibody in Crohn's Disease.

Background: Mast cells can be activated in various ways and were shown to be involved in the development of Crohn's disease (CD). The diagnosis of CD is still challenging, and seeking novel biomarkers is a worthwhile endeavor.

Methods: An indirect enzyme-linked immunosorbent assay (ELISA) was successfully established for semi-quantitative detection of IgG anti-FcεRI in serum using human FcεRIα coated microplates and an enzyme-labeled anti-human IgG as secondary antibodies. The optimal working conditions were explored, followed by conducting the method evaluation. The serum samples and clinical data of 117 CD patients and 75 healthy controls were collected. IgE was measured by the rate turbidity turbidimetry; IgG anti-IgE and IgG anti-FcεRI were detected by ELISA. IgG anti-pancreatic antibody (PAB) and anti-Saccharomyces cerevisiae antibody (ASCA) were determined by indirect immunofluorescence assay. Data were analyzed concerning the clinical characteristics.

Results: IgG anti-FcεRI was an effective marker for CD ( < 0.001), but IgE and IgG anti-IgE ( = 0.089, 0.219, respectively) were not. There was a positive correlation between anti-IgE and anti-FcεRI (R = 0.380, < 0.001). Anti-FcεRI positive patients behaved with higher disease activity [OR: 1.478 (1.200~1.821), < 0.001], but were less likely to be located in L4 among Montreal classification [OR: 0.253 (0.077~0.837), = 0.024]. Existing indicators, PAB and ASCA, behaved with high specificity (both > 95%) with low sensitivity (both < 30%). The combination of anti-FcεRI with existing markers significantly improved the diagnostic efficiency [AUC: 0.879 (0.831~0.928)].

Conclusion: An ELISA for the detection of anti-FcεRI was established and validated, which may contribute to facilitating research on Crohn's diseases. Anti-FcεRI positive CD patients were associated with higher disease activity indices, suggesting its potential value in the diagnosis and management of CD.