Inflammatory subtypes in cough-variant asthma: association with maintenance doses of inhaled corticosteroids.
BACKGROUND
Sputum cell-subtype profiles in cough-variant asthma (CVA) are unknown.


METHODS
Ninety-eight inhaled corticosteroid (ICS)-naive CVA patients were classified according to sputum eosinophil (eos)/neutrophil (neu) counts, as reported in subjects with asthma, as eosinophilic (E) (eos ≥ 1.0%, neu < 61%; n = 28), neutrophilic (N) (eos < 1.0%, neu ≥ 61%; n = 31), mixed granulocytic (M) (eos ≥ 1.0%, neu ≥ 61%; n = 12), and paucigranulocytic (P) (eos < 1.0%, neu < 61%; n = 27) subtypes. Patient characteristics; sputum levels of eosinophil cationic protein (ECP), IL-8, and neutrophil elastase (NE); and daily ICS doses required to maintain control during follow-up (6, 12, 18, and 24 months) were compared, retrospectively.


RESULTS
Subtype N patients, predominantly women, were marginally older than the other subtypes, but FEV(1), airway responsiveness, and total and specific IgE results did not differ. ECP levels were higher in M and E than in N and P subtypes, being similar between M and E or N and P subtypes. Levels of IL-8 and NE were higher in M than in other subtypes, being similar among the latter. ICS doses were initially similar in all subtypes (800 μg equivalent of beclomethasone) but were higher in M than in N and P subtypes throughout follow-up, with E being intermediate between M and N or P subtypes. ICS doses decreased (halved or quartered) in E, N, and P patients followed for 24 months (P < .0001 for all) but remained unchanged in M subjects. IL-8 and NE levels correlated positively with ECP levels.


CONCLUSIONS
In addition to eosinophils, neutrophils, which are possibly activated in the presence of eosinophils, may participate in the pathophysiology of CVA.
Matsuoka
Hirofumi
H
Department of Respiratory Medicine, Kyoto University Graduate School of Medicine, Shogoin, Sakyoku, Kyoto 606-8507, Japan.
Niimi
Akio
A
Matsumoto
Hisako
H
Takemura
Masaya
M
Ueda
Tetsuya
T
Yamaguchi
Masafumi
M
Jinnai
Makiko
M
Inoue
Hideki
H
Ito
Isao
I
Chin
Kazuo
K
Mishima
Michiaki
M
D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000328:Adult; D000704:Analysis of Variance; D001249:Asthma / Q000150:complications / Q000188:drug therapy* / Q000276:immunology / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D015331:Cohort Studies; D003371:Cough / Q000145:classification* / Q000150:complications / Q000276:immunology / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004804:Eosinophils; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009504:Neutrophils; D011014:Pneumonia / Q000150:complications / Q000175:diagnosis*; D012720:Severity of Illness Index; D013183:Sputum / Q000166:cytology* / Q000276:immunology; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D000305:Adrenal Cortex Hormones