Cyclosporin H: a Novel Anti-inflammatory Therapy for Influenza Flu Patients

Relatively little is known about the inflammatory mediators and mechanisms that drive the progression of influenza flu infection to cytokine storm, lung dysfunction, organ failure, and ultimately death. Vaccines and antiviral medications cannot control the excessive host inflammatory response associated with severe influenza flu infection. Studies by Elgebaly et al demonstrated the rapid release of a potent inflammatory mediator, recently named Nourin, by local mammalian tissues in response to injury and infection. Nourin is a formyl peptide that acts through the formyl peptide receptor (FPR) on phagocytic leukocytes. As an initial signal in the innate immunity, Nourin stimulates leukocyte chemotaxis, induces acute and chronic inflammation, and stimulates the release of a number of the cytokine storm mediators from monocytes, neutrophils and endothelial cells. Furthermore, Nourin detected in plasma samples from patients with severe influenza infection was much higher compared to moderate influenza. The Nourin antagonist, Cyclosporin H, is a potent anti-inflammatory compound, which acts as a specific competitive antagonist of formyl peptides on the formyl peptide receptor (FPR) on phagocytic leukocytes. Cyclosporin H completely blocked neutrophil chemotaxis induced by: (a) the standard formyl peptide, f-MLF, (b) the Staphylococcus aureus bacteria-derived formyl peptide Phenol-soluble modulins, such as PSM3a, plus(c) the host-derived Nourin released by: (1) cultured epithelial cells infected with the PR8 H1N1 influenza virus for 6 to 24 hours, (2) Nourin detected in the serum of mouse model of H1N1 Swine flu influenza infection for 6 hours , along with (3) Nourin detected in plasma samples collected from severe and moderate influenza patients. Furthermore, in-vivo treatment by Cyclosporin H in the mouse model of H1N1 Swine flu influenza infection for 5 days markedly reduced lung inflammation and endothelial cell damage. Thus, two clinical applications for Nourin and its antagonist Cyclosporin H are proposed: Diagnostic Application: The blood Nourin test can be used as a key inflammatory biomarker for “early” detection and monitoring of influenza flu patients proceeding to hyperactive inflammation and, thus, permitting early crucial anti-inflammatory therapy. Therapeutic Application: Cyclosporin H will specifically block Nourin as an important initial stimulant of cytokine mediators, and thus can control the development and progression of cytokine storm plus organ inflammation, which usually initiates 3 to 8 days post influenza. Since Cyclosporin H does not target the virus, it will not develop drug resistance and will reduce the host uncontrolled inflammatory response, induced by both new strains of flu viruses and existing viruses with mutations.