A study reported a high ratio of monokine induced by IFN-γ (Mig), and IFN-γ inducible protein 10 (IP 10) in the blood of patients with SARS, and an increase in Mig but not IP-10 in brain tissue, which in turn seems to attract CD68+ macrophages and CD3+ lymphocytes to the sites of virus infection; contributing to brain damage (43). This evidence concerns the gene CXCL9 and severe acute respiratory syndrome.