Interferon-alpha affects the tumour necrosis factor-alpha content of mast cells in human nasal mucosa. A pilot study in allergic patients.

Human nasal mucosal mast cells contain and secrete tumour necrosis factor (TNF)-alpha, which in turn can stimulate histamine secretion by these cells. Interferon (IFN)-alpha can inhibit TNF-alpha secretion by mast cells in vitro. We have addressed the interrelationships between IFN-alpha and the content in TNF-alpha and number of mast cells in vivo, in the human nasal mucosa. Biopsies were taken from two healthy control patients, two allergic patients and two more allergic patients treated topically with IFN-alpha for two weeks; biopsies from the last two patients were taken both before and after stimulation with the specific allergen. Mast cells were counted upon tagging with rhodaminated avidin and by indirect immunofluorescence for TNF-alpha. Data were subjected to analysis of variance. Mast cell numbers were significantly lower in all allergic patients than in controls (P<0.001). Upon IFN-alpha treatment, TNF-alpha positive mast cells were less than in allergic, untreated patients and the opposite was true for TNF-alpha negative mast cells (p<0.05). Allergen challenge caused selective, significant decrease only in the number of TNF-alpha negative mast cells (p<0.05). The results suggest that upon topical IFN-alpha treatment: (1) mast cells stores of TNF-alpha in the nasal mucosa of allergic patients are decreased; and (2) only TNF-alpha negative cells degranulate in response to allergen challenge. Therefore, one may expect that such a treatment reduces the TNF-alpha burden to the mucosa in these patients.