Green tea-induced asthma: relationship between immunological reactivity, specific and non-specific bronchial responsiveness.
BACKGROUND
The relationships between immunological reactivity and bronchial responsiveness to allergen and non-specific bronchial responsiveness are unclear in occupational asthma caused by low molecular weight substances.


OBJECTIVE
We assessed the above relationships in green tea-induced asthma, an occupational asthma of green tea factory workers, in which epigallocatechin gallate (EGCg), a low molecular weight component of green tea leaves, is the causative agent.


METHODS
Subjects consisted of 21 patients suspected of having green tea-induced asthma, on whom skin test and inhalation challenge with EGCg were performed. The skin sensitivity or end-point titration to EGCg as a measure of immunological reactivity, together with the provocative concentrations causing a 20% or greater fall in forced expiratory volume in 1 s (PC20) of EGCg and methacholine, were determined.


RESULTS
We found that 11 patients had green tea-induced asthma, with immediate asthmatic reactions in eight and dual asthmatic reactions in three. We also found that 11 of 13 patients (85%) with immunological reactivity and bronchial hyper-responsiveness to methacholine experienced an asthmatic reaction and that no subject without immunological reactivity reacted. There were significant correlations among skin sensitivity, EGCg PC20 and methacholine PC20. Multiple linear regression analysis showed the relationship: log (EGCg PC20)=0.42 log (skin sensitivity)+1.17 log (methacholine PC20)+0.93 (r=0.796, P<0.05).


CONCLUSIONS
It is concluded that bronchial responsiveness to EGCg can be highly satisfactorily predicted by skin sensitivity to EGCg and bronchial responsiveness to methacholine.
Shirai
T
T
Department of Internal Medicine, Fujinomiya City General Hospital, Fujinomiya, Japan. fmyhsp@lilac.ocn.ne.jp
Reshad
K
K
Yoshitomi
A
A
Chida
K
K
Nakamura
H
H
Taniguchi
M
M
D000328:Adult; D001249:Asthma / Q000276:immunology*; D001980:Bronchi / Q000276:immunology*; D001985:Bronchial Provocation Tests / Q000379:methods; D002392:Catechin / Q000009:adverse effects* / Q000031:analogs & derivatives*; D005260:Female; D005525:Food-Processing Industry; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000276:immunology; D008875:Middle Aged; D008970:Molecular Weight; D009784:Occupational Diseases / Q000276:immunology*; D016273:Occupational Exposure; D011480:Protease Inhibitors / Q000009:adverse effects*; D012867:Skin / Q000276:immunology; D012882:Skin Tests / Q000379:methods; D013662:Tea / Q000009:adverse effects*
D011480:Protease Inhibitors; D013662:Tea; D016210:Methacholine Chloride; D002392:Catechin; C045651:epigallocatechin gallate