Serological investigation of IgG and IgE antibodies against food antigens in patients with inflammatory bowel disease

BACKGROUND Food antigens have been shown to participate in the etiopathogenesis of inflammatory bowel disease (IBD), but their clinical value in IBD is still unclear. AIM To analyze the levels of specific immunoglobulin G (IgG) and E (IgE) antibodies against food antigens in IBD patients and to determine their clinical value in the pathogenesis of IBD. METHODS We performed a retrospective study based on patients who visited the First Affiliated Hospital of Nanjing Medical University between August 2016 and January 2018. A total of 137 IBD patients, including 40 patients with ulcerative colitis (UC) and 97 patients with Crohn's disease (CD), and 50 healthy controls (HCs), were recruited. Serum food-specific IgG antibodies were detected by semi-quantitative enzyme-linked immunosorbent assay, and serum food-specific IgE antibodies were measured by Western blot. The value of food-specific IgG antibodies was compared among different groups, and potent factors related to these antibodies were explored by binary logistic regression. RESULTS Food-specific IgG antibodies were detected in 57.5% of UC patients, in 90.72% of CD patients and in 42% of HCs. A significantly high prevalence and titer of food-specific IgG antibodies were observed in CD patients compared to UC patients and HCs. The number of IgG-positive foods was greater in CD and UC patients than in HCs (CD vs HCs, P = 0.000; UC vs HCs, P = 0.029). The top five food antigens that caused positive specific IgG antibodies in CD patients were tomato (80.68%), corn (69.32%), egg (63.64%), rice (61.36%), and soybean (46.59%). The foods that caused positive specific IgG antibodies in UC patients were egg (60.87%), corn (47.83%), tomato (47.83%), rice (26.09%), and soybean (21.74%). Significantly higher levels of total food-specific IgG were detected in IBD patients treated with anti-TNF alpha therapy compared to patients receiving steroids and immunosuppressants (anti-TNFa vs steroids, P = 0.000; anti-TNF alpha vs immunosuppressants, P = 0.000; anti-TNF alpha vs steroids + immunosuppressants, P = 0.003). A decrease in food-specific IgG levels was detected in IBD patients after receiving anti-TNF alpha therapy (P = 0.007). Patients who smoked and CD patients were prone to developing serum food-specific IgG antibodies [Smoke: OR (95% CI): 17.6 (1.91-162.26), P = 0.011; CD patients: OR (95% CI): 12.48 (3.45-45.09), P = 0.000]. There was no difference in the prevalence of food-specific IgE antibodies among CD patients (57.1%), UC patients (65.2%) and HCs (60%) (P = 0.831). CONCLUSION CD patients have a higher prevalence of food-specific IgG antibodies than UC patients and HCs. IBD patients are prone to rice, corn, tomato and soybean intolerance. Smoking may be a risk factor in the occurrence of food-specific IgG antibodies. Food-specific IgG antibodies may be a potential method in the diagnosis and management of food intolerance in IBD.