Role of polymorphisms of the inflammatory response genes and DC-SIGNR in genetic susceptibility to SARS and other infections.

1. A genetic risk-association study involving more than 1200 subjects showed individuals homozygous for L-SIGN tandem repeats are less susceptible to SARS infection. 2. This was supported by in vitro binding studies that demonstrated homozygous L-SIGN, compared to heterozygous, had higher binding capacity for SARS coronavirus (SARS-CoV), with higher proteasome-dependent viral degradation. In contrast, homozygous L-SIGN demonstrated lower binding capacity for HIV1-gp120.3. Genetic-association studies for single nucleotide polymorphisms of the inflammatory response genes, namely TNF-alpha, INF-alpha, INF-beta, INF-gamma, IL1-alpha, IL1-beta, IL-4, IL-6 and iNOS, failed to show a significant association with SARS clinical outcomes or susceptibility.