[Changes in plasma histamine concentrations following food challenges in children with food allergy]

This study was undertaken to determine whether the measurement of plasma histamine concentrations after food challenges provides an additional predictive marker for the diagnosis of food allergy. In 13 patients who were positive to food antigen-specific IgE, 21 oral food challenges were performed. In 5 non-atopic subjects (controls), 5 oral food challenges were performed in the same way. Plasma histamine concentration was measured by RIA before the challenges and 5, 15, 30, 60, 120, 240 min afterwards. Significant rises in plasma histamine concentrations were observed 120 and 240 min after the challenges in the group of patients who were positive to food challenges. The late onset of the plasma histamine elevation suggests that antigenic macromolecules are absorbed from the small intestine and then reach the target tissues where mast cells release histamine. Even in the group of patients who were negative to food challenges, the peak concentration of the plasma histamine in each patient was significantly higher than it was before challenge. No significant change in plasma histamine concentrations was observed after the challenges in the controls. The results confirmed the strong connection between food allergy and the elevation of plasma histamine concentration, and furthermore they implied the existence of allergic reaction in patients who are negative to food challenges as well as in those who are positive to food challenges. Therefore, plasma histamine concentration following food challenges might be useful markers in the detection of food allergy.