Effect of seasonal allergen exposure on mucosal IL-16 and CD4+ cells in patients with allergic rhinitis.
BACKGROUND
CD4+ T cells constitute a major source of cytokines in allergic diseases such as allergic rhinitis. Interleukin (IL)-16 selectively recruits CD4+ cells.


METHODS
We evaluated the effect of natural allergen exposure during a grass-pollen season on IL-16 expression and number of CD4+ cells in nasal mucosa. Patients with allergic rhinitis (n=16) were treated with either a nasal glucocorticoid beclomethasone (BDP; 400 microg/day) or placebo, and gave nasal biopsies prior to and during the grass-pollen season. The evaluated markers in allergic rhinitis patients were also compared to those in healthy control subjects (n=5).


RESULTS
Prior to the pollen season, the expression of IL-16, but not the number of CD4+ cells, was significantly higher in patients with allergic rhinitis than in healthy control subjects. The grass-pollen season further increased IL-16 expression and also increased the number of CD4+ cells in placebo-treated, but not in BDP-treated, allergic rhinitis patients. The pollen-season-induced change in IL-16 expression and in CD4+ cells was significantly more pronounced in placebo- than in BDP-treated patients. There was a significant correlation between the change in IL-16 expression and the number of CD4+ cells.


CONCLUSIONS
These data suggest that local upregulation of IL-16 expression contributes to the inflammation observed in seasonal allergic rhinitis. Hypothetically, inhibition of IL-16 expression can be one of several mechanisms by which nasal glucocorticoids achieve their anti-inflammatory effect in allergic rhinitis.
Pullerits
T
T
Lung Pharmacology Group, Institute of Heart and Lung Diseases, Department of Respiratory Medicine and Allergology, Göteborg University, Gothenburg, Sweden.
Lindén
A
A
Malmhäll
C
C
Lötvall
J
J
D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000009:adverse effects*; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000918:Antibody Specificity / Q000276:immunology; D001507:Beclomethasone / Q000627:therapeutic use; D001706:Biopsy; D018791:CD4 Lymphocyte Count; D004311:Double-Blind Method; D004781:Environmental Exposure; D005260:Female; D005938:Glucocorticoids; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D019410:Interleukin-16 / Q000032:analysis / Q000502:physiology; D008297:Male; D009297:Nasal Mucosa / Q000737:chemistry* / Q000187:drug effects / Q000473:pathology; D006109:Poaceae / Q000009:adverse effects*; D011058:Pollen / Q000009:adverse effects*; D006255:Rhinitis, Allergic, Seasonal / Q000139:chemically induced* / Q000188:drug therapy / Q000276:immunology*; D012680:Sensitivity and Specificity; D012882:Skin Tests
D000485:Allergens; D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; D019410:Interleukin-16; D007073:Immunoglobulin E; D001507:Beclomethasone