[1] Univ Catania, Azienda Osped Univ Policlin V Emanuele, Ctr Prevenz & Cura Tabagismo, Via S Sofia 78, I-95123 Catania, Italy
[2] Univ Catania, Azienda Osped Univ Policlin Vittorio Ema Nuele, Dipartimento Med Clin & Sperimentale, Via S Sofia 78, I-95123 Catania, Italy
[3] Natl Res Council Italy, Inst Biomed & Mol Immunol, Via Ugo La Malfa 153, I-0146 Palermo, Italy
[4] Univ Hull, Hull York Med Sch, Castle Hill Hosp, Dept Acad Resp Med, Castle Rd, Cottingham HU16 5JQ, England
[5] Univ Brescia, Dept Internal Med, Piazzale Spedali Civili 1, I-25121 Brescia, Italy
[6] AOU Spedali Civili, Piazzale Spedali Civili 1, I-25121 Brescia, Italy