The Pathogenesis of Rheumatoid Arthritis is Associated with Milk or Egg Allergy

Background: Rheumatoid arthritis (RA) is a very complicated autoimmune disease with apparent synovial hyperplasia and cartilage and bone destruction. Aims: In the present study, we aimed to determine whether the pathogenesis of RA correlates with food allergy and which allergen(s) are relevant. Materials and Methods: We used type-II collagen (CII) to induce arthritis (collagen-induced arthritis, CIA) model in Wistar rats, and the development of arthritis was evaluated accordingly by scoring system. Proinflammatory cytokine levels in plasma were measured by enzyme-linked immunosorbent assay (ELISA), and concentrations of circulating immune complexes (CICs) were analyzed by C1q solid phase method. Furthermore, food-specific immunoglobulin G (IgG) and immunoglobulin E (IgE) levels were determined in the CIA model. Results: In the CIA model, we found that levels of tumor necrosis factor-alpha (TNF-a), interleukin (IL)-1, IL-6, and IL-17, as well as CICs, were elevated significantly. Moreover, concentrations of milk- or egg-specific IgG and IgE were enhanced strikingly in CIA rats. Conclusion: The results suggest that pathogenesis of RA correlates closely to increased egg- or milk-specific antibodies.