Diclofenac enhances allergic responses in a mouse peanut allergy model.

Abstract

BACKGROUND: Diclofenac and other non-steroidal anti-inflammatory drugs (NSAIDs) interfere with cyclo-oxygenase-mediated synthesis of prostaglandins, resulting in the inhibition of inflammatory immune responses. In contrast, it is known that NSAIDs are able to induce gastrointestinal damage. OBJECTIVE: Our aim was to investigate whether NSAIDs are able to enhance sensitization or abrogate tolerance to food antigens. METHODS: Mice were exposed to diclofenac and sensitized to peanut using cholera toxin as a mucosal adjuvant. In a tolerance model, oral tolerance was induced via feeding of peanut 3 weeks before sensitization with peanut. Diclofenac was administered before peanut feeding. After 4 weeks, peanut-specific antibodies in the serum and cytokine production in the spleen were measured. Induction of intestinal damage after oral exposure with diclofenac and peanut + cholera toxin was examined microscopically. RESULTS: Diclofenac-exposed animals showed increased levels of peanut-specific IgG1, IgG2a and IgE in the serum compared with vehicle-treated animals. Furthermore, peanut-induced cytokine production in the spleen was elevated upon diclofenac treatment. Importantly, diclofenac did not induce peanut-allergic responses in the absence of the cholera toxin, although exposure to diclofenac and peanut + cholera toxin resulted in intestinal epithelial damage. Reduced peanut-specific antibody production in the case of oral tolerance was not reversed after diclofenac exposure. However, oral tolerance, as measured by inhibition of peanut-specific cytokine responses, was reverted by diclofenac. CONCLUSIONS: These data point towards an increased risk for induction of food-allergic responses by diclofenac, when other circumstances are also in favour of induction of allergy.