AIM: To investigate the role of inflammatory and anti-viral genes in the pathogenesis of SARS. METHODS: cDNA microarrays were used to screen the gene expression profiles of peripheral blood mononuclear cells (PBMCs) in two SARS patients (one in the acute severe phase and the other in the convalescent phase) and a healthy donor. In addition, real-time qualitative PCR was also performed to verify the reproducibility of the microarray results. The data were further analyzed. RESULTS: Many inflammatory and anti-viral genes were differentially expressed in SARS patients. Compared to the healthy control or the convalescent case, plenty of pro-inflammatory cytokines such as IL-1, TNF-α, IL-8, and MAPK signaling pathway were significantly upregulated in the acute severe case. However, anti-inflammatory agents such as IL-4 receptor, IL-13 receptor, IL-1Ra, and TNF-α-induced proteins 3 and 6 also increased dramatically in the acute severe case. On the contrary, a lot of IFN-stimulated genes like PKR, GBP-1 and 2, CXCL-10 and 11, and JAK/STAT signal pathway were downregulated in the acute severe case compared to the convalescent case. CONCLUSION: Gene expression in SARS patients mirrors a host state of inflammation and anti-viral immunity at the transcription level, and understanding of gene expression profiles may make contribution to further studies of the SARS pathogenesis. A: To investigate the role of inflammatory and anti-viral genes in the pathogenesis of SARS. METHODS: cDNA microarrays were used to screen the gene expression profiles of peripheral blood mononuclear cells (PBMCs) in two SARS patients (one in the acute severe phase and the other in the convalescent phase) and a healthy donor. In addition, real-time qualitative PCR was also performed to verify the reproducibility of the microarray results. RESULTS: Many inflammatory and anti-viral genes were differentially expressed in SARS patients. Compared to the healthy control or the convalescent case, plenty of pro-inflammatory cytokines such as IL-1, TNF-α, IL-8, and MAPK signaling pathway were significantly upregulated in the acute severe case. However, anti-inflammatory agents such as IL-4 receptor, IL-13 receptor, IL-1Ra, and TNF-α-induced proteins 3 and 6 also increased dramatically in the acute severe case. On the contrary, a lot of IFN-stimulated genes li ke PKR, GBP-1 and 2, CXCL-10 and 11, and JAK / STAT signaling pathway were downregulated in the acute severe case compared to the convalescent case. CONCLUSION: Gene expression in SARS patients mirrors a host state of inflammation and anti- viral immunity at the transcription level, and understanding of gene expression profiles may make contribution to further studies of the SARS pathogenesis.