To compare serum antibody activity against dietary antigens in patients with rheumatoid arthritis (RA) and healthy controls, and to examine whether anti-food antibody activity fluctuated with disease activity during a trial of fasting followed by a one-year vegetarian diet.
Serum IgG, IgA and IgM antibody activity against several food antigens was measured by an enzyme immunoassay. Abnormally high antibody activity was defined as values above the 90th percentile of the measurements in 30 healthy controls. Serum IgE antibody activity was measured by a radioallergosorbent test.
During the trial 10 of 27 patients suspected that certain food items aggravated their arthritis symptoms. Elevated antibody activity against one or more of the dietary antigens was found in all RA patients, but these measurements could not be used to predict which food would aggravate the symptoms. Elevated IgG and IgA antibody activity against alpha-lactalbumin was found in a significantly larger number of RA patients than in controls. With the exception of one patient, there was no concordance between the clinical course and antibody activity against the various dietary antigens.
The results indicate that a systemic humoral immune response against food items is probably not involved in the pathogenesis of RA.