Inhaled formaldehyde exposure: effect on bronchial response to mite allergen in sensitized asthma patients.
BACKGROUND
Formaldehyde, an indoor air pollutant, is known to be an irritant and an etiologic factor in occupational asthma. An epidemiologic study suggests that it may also increase the risk of childhood asthma for concentrations above 60 microg/m(3).


OBJECTIVE
To evaluate the influence of pre-exposure to low-dose formaldehyde (100 microg/m(3) in 30 min according to the World Health Organization's recommended maximum value for indoor environments) on bronchial response to Dermatophagoides pteronyssinus.


METHODS
Nineteen asthmatic subjects were included. Each subject underwent a mite allergen bronchial challenge test immediately after a standardized exposure in a chamber to formaldehyde or air (random order). Induced sputum were collected 24 h before and after mite challenge.


RESULTS
After formaldehyde inhalation, patients developed an immediate bronchial response at a significantly lower dose of mite allergen than after air exposure (the geometric mean PD(20) for Der p 1 was 34.3 ng after formaldehyde and 45.4 ng after placebo, P = 0.05). The late-phase reaction, expressed as the maximum fall in forced expiratory volume in 1 s (FEV(1)) from baseline, was significantly higher after formaldehyde (15%vs 11%, P = 0.046).


CONCLUSIONS
Our study demonstrated that exposure to low levels of formaldehyde significantly enhanced bronchial responsiveness to mite allergen in mite-sensitized subjects with asthma.
Casset
A
A
Département de Pneumologie, Hôpital Lyautey, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Marchand
C
C
Purohit
A
A
le Calve
S
S
Uring-Lambert
B
B
Donnay
C
C
Meyer
P
P
de Blay
F
F
D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000276:immunology*; D060829:Arthropod Proteins; D001249:Asthma / Q000139:chemically induced / Q000209:etiology* / Q000276:immunology; D001980:Bronchi / Q000187:drug effects / Q000276:immunology; D003546:Cysteine Endopeptidases; D040002:Dermatophagoides pteronyssinus / Q000276:immunology; D047150:Eosinophil Cationic Protein / Q000097:blood; D005260:Female; D005557:Formaldehyde / Q000633:toxicity*; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D013183:Sputum / Q000166:cytology
D000393:Air Pollutants; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D016210:Methacholine Chloride; D005557:Formaldehyde; D047150:Eosinophil Cationic Protein; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1