Immunopathologie de la rhinite allergique

Nasal response to allergen and hyperosmolar challenge

Rhinitis causes both clinical and social discomfort to patients, and in clinical practice is often underdiagnosed. We have examined a simple method for the assessment of a positive nasal provocation test to help in the diagnosis of rhinitis. In patients with histories suggestive of house dust mite (HDM) sensitivity and positive skin-prick tests or specific IgE to Dermatophagoides pteronyssinus, there was a fall in nasal inspiratory peak flow (NIPF) following nasal challenge with allergen. This was not seen in control subjects or in pollen-sensitive patients when challenged with house dust mite. Frequency of sneezing and degree of rhinorrhoea increased in these patients following challenge, and based on these findings we propose a simplified scoring system for the diagnosis of allergic rhinitis. We examined non-specific nasal reactivity using hyperosmolar solutions as a challenge system and found that allergic subjects responded with a fall in NIPF, although the clinical response was not identical to that seen with allergen. Control subjects did not respond to hyperosmolar challenge.

Nasal challenge with serotonin in asymptomatic hay fever patients

To study the nasal response to serotonin, 14 asymptomatic hay fever patients received intranasal serotonin in increasing doses. Itching and the number of sneezes were noted, and the amount of secretion was measured and assayed for substance P. Nasal airway resistance was recorded by active posterior rhinomanometry. Serotonin induced a dose-dependent increase in nasal itching, number of sneezes and secretion. Substance P was found in 41 of 42 secretions. The median concentration was 10.3 pmol/l (range 0-28.9), and increased parallel to increasing doses of serotonin (P less than 0.001).