Cessation of passive smoking reduces allergic responses and plasma neurotrophin

Sir, Passive smoking enhanced allergic sensitization in the general population, while it enhanced allergic skin wheal responses in patients with atopic eczema/dermatitis syndrome (AEDS) [1,2]. Blood levels of neurotrophins, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), were elevated in atopic patients [3,4]. Moreover, NT-4 expression in epidermal keratinocytes was markedly augmented in patients with AEDS [5]. The effect of cessation of passive smoking on allergic responses and plasma neurotrophin was studied. After obtaining informed consent from the patients’ parents, who smoked 10–15 cigarettes per day at home, 25 normal children and 50 children with mild AEDS were studied. All of the patients had mild skin symptoms according to the Scoring Atopic Dermatitis (SCORAD) index and were allergic to house dust mite and cat dander, although they never had cats in their houses (Table 1) [2]. It is well known that atopic patients are sensitive to cat dander or dog dander despite not having these pets at home. All of the patients and control subjects were recruited from the outpatients’ clinic of the Department of Allergy & Pediatrics. Fifty patients with AEDS were randomly divided into (1) continuation of passive smoking group (12 female and 13 male, mean age 12 years, range 11–14 years) and (2) cessation of passive smoking group (13 female and 12 male, mean age 12 years, range 10–14 years), while 25 normal children (12 female and 13 male, mean age 12 years, range 11–14 years) were assigned to cessation of passive smoking group. A total of different 75 persons were administered in the study. Parents of the cessation of passive smoking group agreed to stop smoking. Urinary cotinine levels (mean ± SD) in the children at baseline vs. after 1 month: 274 ± 42 ng mL − 1