Substance P-immunoreactive nerves in endobronchial biopsies in cough-variant asthma and classic asthma.
BACKGROUND
Unlike classic asthma, cough-variant asthma does not show any evidence of airway obstruction. The main symptom is a dry cough with little known pathophysiology. Hypersensitivity of the cough receptors in cough-variant asthma and an increase in the sensory nerve density of the airway epithelium in persistent dry cough patients have been reported. Therefore, it is possible that there is a higher sensory nerve density in cough-variant asthma patients than in classic asthma patients.


OBJECTIVE
This study was undertaken to compare the substance P (SP)-immunoreactive nerve density in mucosal biopsies of cough-variant asthma patients, classic asthma patients, and in control subjects.


METHODS
Bronchoscopic biopsies were performed in 6 cough-variant asthma patients, 14 classic asthma patients, and 5 normal controls. The tissues obtained were stained immunohistochemically. The SP-immunoreactive nerve density was measured in the bronchial epithelium using a light microscope at 400 x magnification.


RESULTS
SP- immunoreactive nerve density for the cough-variant asthma group was significantly higher than that of the classic asthma group (p = 0.001), and of the normal control group (p = 0.006).


CONCLUSIONS
It is possible that a sensory nerve abnormality within the airway may be related to hypersensitivity of the cough receptor, and that this may be one of the pathophysiologies of cough-variant asthma.
Lee
Sang Yeub
SY
Pulmonary Division, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Korea.
Kim
Min Kyung
MK
Shin
Chol
C
Shim
Jae Jeong
JJ
Kim
Han Kyeom
HK
Kang
Kyung Ho
KH
Yoo
Se Hwa
SH
In
Kwang Ho
KH
D000328:Adult; D001249:Asthma / Q000145:classification / Q000378:metabolism*; D001706:Biopsy; D001980:Bronchi / Q000294:innervation / Q000378:metabolism*; D016085:Bronchoconstrictor Agents; D003371:Cough / Q000378:metabolism*; D003627:Data Interpretation, Statistical; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008853:Microscopy; D008875:Middle Aged; D009412:Nerve Fibers / Q000378:metabolism / Q000648:ultrastructure*; D012720:Severity of Illness Index; D013373:Substance P / Q000378:metabolism*
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D013373:Substance P