Smoking and HP

Q: Cigarette smoking may have a preventive effect on hypersensitivity pneumonitis (HP).

A) True

B) False

Answer: A

Cigarette smoking has a paradoxical effect on HP, meaning it is associated with a decreased risk of HP! This was found universal on all forms of HP, including farmer's lung, pigeon breeder's disease, contaminated air conditioners induced HP, and Japanese summer-type HP (Trichosporon cutaneum). 

This paradox gets trickier in the sense that once HP occurs, smoking does not attenuate its severity, but rather may cause a more chronic and severe course. This predisposition to a chronic course appears to be associated with a less pronounced production of IgG antibody in smokers.  Fortunately, this effect of smoking is reversible.

#pulmonary

#immunology

References:

1. Murin S, Bilello KS, Matthay R. Other smoking-affected pulmonary diseases. Clin Chest Med 2000; 21:121.

2. Arima K, Ando M, Ito K, et al. Effect of cigarette smoking on prevalence of summer-type hypersensitivity pneumonitis caused by Trichosporon cutaneum. Arch Environ Health 1992; 47:274.

3. McSharry C, Banham SW, Boyd G. Effect of cigarette smoking on the antibody response to inhaled antigens and the prevalence of extrinsic allergic alveolitis among pigeon breeders. Clin Allergy 1985; 15:487.

4. Ohtsuka Y, Munakata M, Tanimura K, et al. Smoking promotes insidious and chronic farmer's lung disease, and deteriorates the clinical outcome. Intern Med 1995; 34:966.