SARS-CoV virus-host interactions and comparative etiologies of acute respiratory distress syndrome as determined by transcriptional and cytokine profiling of formalin-fixed paraffin-embedded tissues

These studies attempt to understand more fully the host response and pathogenesis associated with severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) by monitoring gene expression using formalin-fixed paraffin-embedded (FFPE) pulmonary autopsy tissues. These tissues were from patients in different hospitals in Singapore who were diagnosed with various microbial infections, including SARS-CoV, that caused acute respiratory distress syndrome (ARDS). Global expression patterns showed limited correlation between end-stage ARDS and the initiating pathogen, but when focusing on a subset of genes implicated in pulmonary pathogenesis, molecular signatures of pulmonary disease were obtained and appeared to be influenced by preexisting pulmonary complications and also bacterial components of infection. Many factors detected during pulmonary damage and repair, such as extracellular matrix (ECM) components, transforming growth factor (TGF) enhancers, acute-phase proteins, and antioxidants, were included in the molecular profiles of these ARDS lung tissues. In addition, differential expression of cytokines within these pulmonary tissues were observed, including notable genes involved in the interferon (IFN) pathway, such as Stat1, IFN regulatory factor-1 (IRF-1), interleukin-6 (IL-6), IL-8, and IL-18, that are often characterized as elevated in ARDS patients.