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Abstract Chronic Obstructive Pulmonary Disease (COPD), a common disease, is characterized by persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung to noxious particles or gases. Exacerbations and co morbidities contribute to the overall severity in individual patients. Pulmonary surfactant consists of about 3% of two hydrophobic lipoproteins (SP-B and SP-C), 3-6% of two hydrophilic lipoproteins (SP-A and SP-D) and approximately 90% of lipids which consist of equimolar amounts of saturated and unsaturated phospholipid species and cholesterol. SP-D is thought to play an important role in the pathogenesis of COPD by oxidant production, inflammatory responses in alveolar macrophages and apoptotic cell clearance. Within the SP-D gene, the three SNPs Met11Thr, Ala160Thr and Ser270Thr are of potential functional relevance. Rs721917 is a missense substitution which leads the replacement in position 11 of an ancestral methionine by a threonine (Met11Thr). Subjects carrying TT -genotype (Met/Met) have increased concentrations of SP-D in plasma, and show multimers, dodecamers, and monomers of subunits, whereas CC -carriers (Thr/Thr) produce almost exclusively monomers. The SNP rs3088308 causes a substitution of nucleotide adenine (A) in place of a thymidine (T) in the seventh exon of the SFTPD gene leading to the replacement of serine (Ser) by threonine (Thr) at position number 270 in the CRD of SP-D protein molecule. Theis residue corresponds to the carbohydrate recognition domain of the mature protein which binds various pathogens as well as apoptotic cells. Rs721917 is associated with increased susceptibility to tuberculosis, Influenza A virus, infection, allergic rhinitis,COPD, RSV infection in infants, atopy and blood levels of SP-D. The current study was carried out at Medical Biochemistry and Chest diseases & Tuberculosis Departments, Faculty of Medicine, Menoufia University. The study was carried out on76 subjects.The patients were attendants of outpatient and inpatients of Chest diseases and Tuberculosis Department, Menoufia University Hospitals during the period from April 2014 to April 2015. |