title: Authors' reply.
authors.affiliation: Department of Pulmonary Medicine, Nil Ratan Sircar Medical College and Hospital, Shealdah, Kolkata, West Bengal, India.
authors.forename: Amitabha
authors.initials: A
authors.lastname: Sengupta
authors.affiliation: Department of Pulmonary Medicine, Burdwan Medical College and Hospital, Burdwan, West Bengal, India E-mail: doctorkaushiksaha@gmail.com.
authors.forename: Kaushik
authors.initials: K
authors.lastname: Saha
authors.affiliation: Department of Pulmonary Medicine, Nil Ratan Sircar Medical College and Hospital, Shealdah, Kolkata, West Bengal, India.
authors.forename: Debraj
authors.initials: D
authors.lastname: Jash
authors.affiliation: Department of Pulmonary Medicine, Nil Ratan Sircar Medical College and Hospital, Shealdah, Kolkata, West Bengal, India.
authors.forename: Sourindra Nath
authors.initials: SN
authors.lastname: Banerjee
authors.affiliation: Department of Pulmonary Medicine, Nil Ratan Sircar Medical College and Hospital, Shealdah, Kolkata, West Bengal, India.
authors.forename: Nirendra Mohan
authors.initials: NM
authors.lastname: Biswas
authors.affiliation: Department of Pulmonary Medicine, R G Kar Medical College and Hospital, Kolkata, West Bengal, India.
authors.forename: Atin
authors.initials: A
authors.lastname: Dey