Pollen starch granules in bronchial inflammation.
BACKGROUND
Pollen grains with a diameter of more than 10 μm preferentially deposit in the upper airways. Their contribution to lower airway inflammation is unclear. One hypothesis is that lower airway inflammation is mainly caused by allergen containing pollen starch granules, which are released from the pollen grains and can easily enter the peripheral airways because of their smaller size.


OBJECTIVE
To investigate the differential effect of pollen grains and pollen starch granules on nasal symptoms and lower airway inflammation.


METHODS
In a 2-period crossover design, 30 patients with allergic rhinitis and mild intermittent asthma underwent 2 allergen challenges on consecutive days in an environmental challenge chamber with either a mixture of pollen grains plus starch granules or starch granules only. End points were the total nasal symptom score (TNSS), nasal secretion weight, nasal flow, spirometry, and exhaled nitric oxide (eNO).


RESULTS
The presence of pollen grains had a significant and considerable effect on increase in TNSS and secretion weight and on decrease in nasal flow. Starch granules alone only had minimal effects on nasal symptoms. Challenges with starch granules significantly increased eNO. Pollen had no effect on eNO.


CONCLUSIONS
Pollen grains cause nasal symptoms but do not augment lower airway inflammation, whereas starch granules trigger lower airway inflammation but hardly induce nasal symptoms.
Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany. philipp.badorrek@item.fraunhofer.de
Philipp
P
Badorrek
Melanie
M
Dick
Lorenz
L
Emmert
Frank
F
Schaumann
Wolfgang
W
Koch
Hartmut
H
Hecker
Robert
R
Murdoch
Jens M
JM
Hohlfeld
Norbert
N
Krug
D000328:Adult; D000485:Allergens / Q000276:immunology*; D001249:Asthma / Q000276:immunology / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009299:Nasal Provocation Tests; D009569:Nitric Oxide / Q000096:biosynthesis; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology / Q000503:physiopathology*; D013213:Starch / Q000276:immunology*; D055815:Young Adult
D000485:Allergens; D009569:Nitric Oxide; D013213:Starch