Objectives: Specific food antigens, such as gliadins and caseins, have been well documented as triggering immune reactivity to human tissues, due to cross-reactivity or molecular mimicry. Food antigens, such as agglutinins, are known to bind to human tissues, which can result in autoantibodies. This study aimed to examine the correlation between food protein antibodies and tissue antibodies.

Method: We selected 118 patients on whom food and tissue antibodies were simultaneously measured in our laboratory. Data was collected on patient IgG reactivity to wheat gliadins and glutenin; IgG+IgA reactivity to caseins, milk butryophilin and other milk proteins; and IgG reactivity to wheat germ agglutinin (WGA) and IgG+IgA reactivity to other food lectins/agglutinins. We compared the tissue IgG+IgA positivity between patients positive for food antibodies versus patients negative for food antibodies. Results: Of 45 patients negative for IgG against gluten proteins, 16 (35%) were reactive against one or more tissues, while of 45 positive for IgG against gluten proteins, 29 (64%) were reactive against tissues.

Of 30 patients negative for dairy proteins antibodies, 9 (30%) were reactive against one or more tissues, while of 30 patients positive for dairy antibodies, 22 (73%) were reactive against tissues. Of 25 patients negative for IgG against WGA, 8 (22%) were reactive against one or more tissues, while of 25 patients positive for IgG against WGA, 19 (76%) were reactive against tissues. Conclusion: Patients with antibody reactivity to specific food proteins showed higher co-occurrence of tissue autoantibodies than patients without food reactivities. More studies are needed to assess the long-term role of diet on the onset and management of autoimmunity.