[Recurrent aphthous stomatitis: which role for viruses, food, and dental materials?].

Recurrent aphthous stomatitis is a frequently occurring disorder which may be a clinical feature of systemic disease. For many other patients, it is a tedious problem often having no known cause. The aim of this study was to verify if immune responses to common foods and/or viruses are involved in the etiopathogenesis of recurrent aphthous stomatitis. Sixteen patients with this disorder were studied by measurement of immunoglobulin classes (IgG, IgA, IgM), blood lymphocyte subpopulations, blood circulating immune complexes, and complement fractions (C3 and C4). Intradermal skin tests for common food and inhalant allergens were performed in all cases. In 5 patients with positive skin tests, serum specific IgE were tested for the same allergens by radioallergosorbent test. Skin patch tests for dental material were performed in all cases. Oral mucosal biopsies and/or cytology samples were taken in 10 cases for histopathological evaluation and in situ hybridization for Papillomavirus, Cytomegalovirus, Herpes simplex virus I and II, Epstein Barr virus. In 13 patients, lymphocyte subpopulations were altered, with a reduced CD4/CD8 ratio. No other alterations of serum immunological parameters were observed. Skin patch tests for dental material were negative in all cases, while skin tests for food allergens were positive in 5 cases (not confirmed by radioallergosorbent test or food challenge tests). Virus antigen and DNA were not found in mucosal specimens, although one patient was positive for Epstein Barr virus DNA by in situ hybridization. An alteration of the CD4/CD8 ratio was demonstrated in most of the patients with recurrent aphthous stomatitis, although immune responses to food and/or dental material and/or common viruses did not seem to be involved in the etiopathogenesis of this disorder.