Immunohistological findings in lip biopsy specimens from patients with Crohn's disease and healthy subjects.

Biopsies of apparently normal buccal mucosa were taken from 14 patients with Crohn's disease and 13 healthy controls who were matched for dental status. Most patients had an increased number of lymphocytes around vessels in the subepithelial tissue and two showed fibrosis with moderate atrophy of minor glands. Plasma cells which contained immunoglobulin, predominantly IgA, were only found around minor salivary glands in both patients and controls. Quantitative studies showed a significant increase in the number of cells containing IgA in patients compared with controls. No correlation was found between immunoglobulin pattern and disease activity, age, sex, or duration of Crohn's disease. A significant correlation was found between the activity of the disease, as defined by the Crohn's Disease Activity Index, and the number of plasma cells containing IgM.