PT - JOURNAL ARTICLE AU - Dalia Fakih AU - Soulaima Chamat AU - Myrna Medlej-Hashim AU - Mirna Waked AU - Pascale Salameh AU - Grith Sorensen AU - Rania Jounblat TI - Polymorphism in <em>SFTPD</em> gene affects assembly and constitutional serum levels of surfactant protein D in a Lebanese population DP - 2014 Sep 01 TA - European Respiratory Journal PG - P4784 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P4784.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P4784.full SO - Eur Respir J2014 Sep 01; 44 AB - Surfactant protein D (SP-D), an oligomeric lung-derived lectin, has essential roles in innate immunity. It can be measured in serum. Previous studies have shown that constitutional SP-D serum levels and the protein degree of multimerization are genetically influenced. We aimed to establish the distribution profile of serum constitutional SP-D in the Lebanese population and to investigate the genetic influence of single nucleotide polymorphism (SNP) rs721917 within SP-D gene (SFTPD) on its multimerization and its serum basal level. The C/T alleles at this SNP level lead respectively either to a threonine or methionine at position 11 of the SP-D protein. SP-D was measured by ELISA in serum taken from 97 healthy subjects. The p.Met11Thr SNP was genotyped. Different forms of SP-D were separated by gel filtration chromatography. Basal serum SP-D levels varied extensively, over a range of 108.3 ng/ml to 2995 ng/ml. The p.Met11Thr SNP was significantly associated with the serum SP-D levels (p=0.01). Individuals homozygous for the T wild-type allele had the highest mean SP-D serum levels (1423 ng/ml) compared to heterozygous individuals (1139 ng/ml) and homozygous individuals for the C allele (671.4 ng/ml). Serum from heterozygous individuals showed two different molecular weight peaks corresponding to different forms of SP-D of ratio high/low 1:07. However, data showed a remarkable predominance of the low molecular weight form of SP-D (ratio high/low 1:4.65) in serum of individuals carrying the CC genotype. Our preliminary findings validate previous observations of the influence of the p.Met11Thr SNP on assembly and serum concentration of SP-D.