In this context, increased levels of proinflammatory cytokines have been reported, not only in the acute phase of SARS, particularly interleukin-6 (IL-6), but also in advanced stages of the disease, even in patients requiring invasive mechanical ventilation (IMV), such as IL-6, interleukin-8 (IL-8), interleukin-9 (IL-9), interleukin-17 (IL-17), interferon gamma-induced protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1), granulocyte-colony stimulating factor (G-CSF), macrophage inflammatory protein-1-alpha (MIP-1) and chemokine ligand 5 (RANTES) [6,7]. This evidence concerns the gene IL9 and severe acute respiratory syndrome.