Immunomodulating effects of 13-cis-Retinoic acid on the IgE response of BALB/c mice.

The results reported here are an extension of our previously reported studies on the adjuvant effects of 13-cis-retinoic acid (13-cRA). Previous results, as well as those reported herein, show the lack of a primary IgE response with elevated and sustained secondary IgE responses in animals treated with 13-cRA. It was determined that this lack of a primary IgE response was not due to overt immunotoxicity by 13-cRA, suggesting that 13-cRA is priming a population of memory cells; however, either the formation of suppressor cells or the lack of an appropriate stimulus at the time of primary immunization also prevented a demonstrable primary IgE antibody response. It was also demonstrated that the absence of a primary response was not due to a sensitivity of the immune system to the timing of the administration of 13-cRA relative to immunization, as all animals given 13-cRA at either day -2, -1, 0, 1, 2 or 3 relative to primary immunization showed no primary response but high secondary IgE responses. These experiments, which closely mimic the clinical treatment regimen, indicate that patients receiving retinoid therapy should be closely monitored for immunological side effects, such as immediate hypersensitivity to environmental allergens.