CD209 (DC-SIGN) −336A>G promoter polymorphism and severe acute respiratory syndrome in Hong Kong Chinese

CD209 (DC-SIGN) is an important C-type lectin which acts a receptor of many pathogens. The single nucleotide polymorphism (SNP) −336A>G in the CD209 promoter has been demonstrated to regulate promoter activity and to be associated with several important infectious diseases, such as human immunodeficiency virus–1 (HIV-1), Mycobacterium tuberculosis, and Dengue fever. CD209 facilitates severe acute respiratory syndrome (SARS)–coronavirus spike protein-bearing pseudotype driven infection of permissive cells in vitro. In keeping with previously published findings, our in vitro studies confirmed that this SNP modulates gene promoter activity. Genetic association analysis of this SNP with clinico-pathologic outcomes in 824 serologic confirmed SARS patients showed that the −336AG/GG genotype SARS patients was associated with lower standardized lactate-dehydrogenase (LDH) levels compared with the −336AA patients (p = 0.014, odds ratio = 0.40). High LDH levels are known to be an independent predictor for poor clinical outcome, probably related to tissue destruction from immune hyperactivity. Hence, SARS patients with the CD209 −336 AA genotype carry a 60% chance of having a poorer prognosis. This association is in keeping with the role of CD209 in modulating immune response to viral infection. The relevance of these findings for other infectious diseases and inflammatory conditions would be worth investigating.