Patients with subjective food hypersensitivity: the value of analyzing intestinal permeability and inflammation markers in gut lavage fluid

Background/Aim: Subjective food hypersensitivity is prevalent in the general population. The aim of this study was to seek objective evidence of food hypersensitivity by analyzing intestinal permeability and inflammation markers in gut lavage fluid. Methods: Fifty-two patients with abdominal complaints self-attributed to food hypersensitivity were examined by skin prick test, serum IgE analysis, double-blind, placebo-controlled food challenge (DBPCFC), and intestinal lavage. The results were compared with those of 44 patients without food hypersensitivity. Neither the patients nor the controls had organic diseases that could explain their symptoms. Intestinal lavage was performed by administering 2 liters of isotonic polyethylene glycol (molecular weight 3,350 daltons) solution containing 50 µCi of [51Cr]EDTA through a nasoduodenal tube. The first clear fluid passed per rectum was collected and analyzed for histamine, eosinophilic cationic protein (ECP), tryptase, and calprotectin. The intestinal permeability was assessed by determining the 5-hour urinary excretion of [51Cr]EDTA. Calprotectin was also analyzed in native faecal samples. Results: The ECP concentration in gut lavage fluid was significantly higher in the patients than in the controls (p = 0.007), but the overlap between groups was large. Food hypersensitivity was confirmed by positive DBPCFC in only 4 patients. On average, histamine and ECP concentrations were high in these patients. Tryptase, intestinal permeability, and faecal and lavage calprotectin levels were normal. Conclusions: Very few patients had objective evidence of food hypersensitivity. Analyzing intestinal permeability and inflammation markers in gut lavage fluid did not contribute to the diagnosis, but further studies on histamine and ECP are warranted.