Nasal eosinophilia in children: its use in the nasal allergen provocation test

Examen virologique des sécrétions nasopharyngées et examen cytobactériologique de l'expectoration

Les sécrétions nasopharyngées et bronchiques se prêtent à différents examens bactériologiques, virologiques et autres. Assez courants à l'hôpital, ils sont beaucoup moins utilisés en pédiatrie ambulatoire. Néanmoins, pour que leurs résultats soient interprétables et utiles au diagnostic, la technique de prélèvement doit être soigneuse. L'intérêt pratique de ces examens mérite également d'être précisé pour que les demandes soient justifiées.

Diagnostic value of nasal provocation challenge with allergens in children

A total of 106 children suffering from perennial rhinitis and/or asthma, and all allergic to Dermatophagoides pteronyssinus (DP), underwent nasal provocation challenge (NPC) with DP to determine the best method of diagnosis. Posterior rhinomanometry was uninterpretable in 17 patients and gave negative results in 31. Clinical scores for sneezing and rhinorrhea were more effective but did not diagnose the disorder in 11 children. However, nine of the 11 had significant increases in eosinophil count in the late phase. Clinical scores and cytology were also useful for assessing whether NPC with allergens was positive in children. The feasibility and safety of NPC with DP are high for rhinitic and stable asthmatic patients, but mild reactions may occur during the late phase.

Nasal cytology in rhinitis children: comparison between brushing and blowing the nose

Allergic rhinitis is a common disease in childhood, but nasal cytology is rarely used by pediatricians. We compared two techniques of cell sampling, brushing and blowing the nose, among 77 children suffering from chronic rhinitis, of whom 59 were allergic. Staining by the May-Grunwald-Giemsa method enabled the evaluation of the density of cells and especially differential counting of the inflammatory cells. Staining by the Luna method was used as a control for the eosinophils. For the eosinophil count, we found a strong correlation between the two methods of collecting the nasal secretions (r = 0.96). Because blowing the nose is painless and easy to perform, it is more appropriate than brushing in routine use for the diagnosis of allergic rhinitis in children and in nasal challenge with allergens.

Diagnostic value of the nasal provocation test with Dermatophagoides pteronyssinus in childhood asthma

We aimed to determine whether the nasal provocation test (NPT) with allergen could be used as a diagnostic test in asthmatic children with or without allergic rhinitis, and whether it had any effects on pulmonary function tests and arterial oxygen saturation (SaO2) values. Therefore, 25 asthmatic outpatients sensitive to Dermatophagoides pteronyssinus (Dp), aged 6-17 years, 12 having allergic rhinitis, and 10 nonatopic children as a control group were challenged intranasally with solution containing Dp extract by administration of a total dose of 800-1000 AU to both nasal cavities. Before the test and 10 min and 20 min after the administration of the allergen intranasally, the nasal expiratory peak flow (NEPF), pulmonary function tests, and SaO2 were measured. In the NPT, a decrease of 20% or more in NEPF and occurrence of nasal symptoms were considered to be positive. NPT was positive in all the asthmatic patients with or without allergic rhinitis, while all the children in the control group had a negative test. Compared to values prior to the test, values of FEV1 (forced expiratory volume in 1 s) and SaO2 showed no statistically significant decrease, and no clinically significant asthmatic reaction was observed in any of the groups. Our study suggests that in asthmatic children with or without allergic rhinitis, the NPT with allergen is a simple, safe, and useful diagnostic test.

Mast cells and eosinophils in the allergic mucosal response to allergen challenge: changes in distribution and signs of activation in relation to symptoms

An allergen challenge was performed in 10 asymptomatic patients with strictly seasonal allergic rhinitis. For comparison; seven nonallergic subjects were challenged with allergen, and seven allergic patients were challenged with diluent. Cell samples, obtained with use of a brush technique to recover cells from within the epithelium and nasal lavage to collect cells from the epithelial surface, and symptom scores were taken before challenge and at 2-hour intervals during 12 hours. The cell suspensions were cytocentrifuged onto object slides for light microscopy. Histamine was determined in the cell pellets. In brush samples from the allergic patients challenged with allergen, eosinophils, expressed as a percentage of the total granulocytes, increased from 4.3% +/- 2.7% (mean +/- SEM) to 10.3% +/- 3.8% (p < 0.05) 4 hours after challenge. This level was maintained for up to 12 hours. A similar increase was noted in the lavage specimens 2, 6, and 8 hours after the challenge. In the brush samples the proportion of eosinophils containing two or more cytoplasmic vacuoles, taken as a sign of activation, increased from 20% to 72% (p < 0.05) 8 hours after provocation. In brush samples from the allergic patients challenged with allergen, the numbers of metachromatic cells increased to a maximum of eightfold at 10 hours. In the lavage specimens, no metachromatic cells were observed before provocation, but they progressively increased in number 2 to 12 hours after provocation. Cell pellet histamine content decreased temporarily 2 to 4 hours after challenge (p < 0.05) in brush samples from allergen-challenged allergic patients. The local metachromatic cell density before challenge, as reflected in the brush specimens, correlated with nasal congestion, sneezing, and the degree of eosinophilia.