Protein nitration in chronic sinusitis and nasal polyposis: role of eosinophils.
OBJECTIVE
To investigate the possible role of eosinophil peroxidase (EPO) in 3-nitrotyrosine (3NT) formation.


METHODS
Observational study employing immunocytochemistry to assess the presence of 3NT, inducible nitric oxide synthase (iNOS), eosinophils, mast cells, neutrophils, and lymphocytes in ethmoid sinus mucosal biopsies from normal controls and subjects with allergic and nonallergic chronic sinusitis and nasal polyposis.


RESULTS
3NT was more evident in biopsies from sinusitis patients (2.67 +/- 0.14, n = 21) than in healthy mucosa (0.43 +/- 0.2, n = 7, P < 0.01), but scores in atopic and nonatopic subjects were similar. Colocalization studies confirmed that 3NT was largely confined to eosinophils. No relationship was found between 3NT and other immune cells. 3NT detection was not correlated with the amount of immunostaining for iNOS.


CONCLUSIONS
Chronic sinusitis is accompanied by 3NT formation, which is largely restricted to the eosinophils, and likely driven by the action of eosinophil peroxidase, rather than by nitric oxide levels.


METHODS
B-2.
Bernardes
Julio Freire
JF
Meakins-Christie Laboratories, Respiratory Division, Department of Medicine, McGill University Health Centre, Montreal, QC H2X 2P2, Canada.
Shan
Jichuan
J
Tewfik
Marc
M
Hamid
Qutayba
Q
Frenkiel
Saul
S
Eidelman
David H
DH
D000328:Adult; D000368:Aged; D002908:Chronic Disease; D047209:Eosinophil Peroxidase / Q000378:metabolism*; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000276:immunology*; D012852:Sinusitis / Q000276:immunology*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000096:biosynthesis*
C002744:3-nitrotyrosine; D014443:Tyrosine; D047209:Eosinophil Peroxidase