Proposed mechanism of benefit
The Italian study findings that biologics boost the risk of infection with the SARS-CoV-2 virus in psoriasis patients while potentially protecting them against ICU admission and death are backed by a biologically plausible albeit as yet unproven mechanism of action, Dr. Damiani asserted.
He elaborated: A vast body of high-quality clinical trials data demonstrates that these targeted immunosuppressive agents are associated with modestly increased risk of viral infections, including both skin and respiratory tract infections. So there is no reason to suppose these agents would offer protection against the first phase of COVID-19, involving SARS-CoV-2 infection, nor protect against the second (pulmonary phase), whose hallmarks are dyspnea with or without hypoxia. But progression to the third phase, involving hyperinflammation and hypercoagulation – dubbed the cytokine storm – could be a different matter.
“Of particular interest was that our patients on IL-17 inhibitors displayed a really great outcome. Interleukin-17 has procoagulant and prothrombotic effects, organizes bronchoalveolar remodeling, has a profibrotic effect, induces mitochondrial dysfunction, and encourages dendritic cell migration in peribronchial lymph nodes. Therefore, by antagonizing this interleukin, we may have a better prognosis, although further studies are needed to be certain,” Dr. Damiani commented.
Publication of his preliminary findings drew the attention of a group of highly respected thought leaders in psoriasis, including James G. Krueger, MD, head of the laboratory for investigative dermatology and codirector of the center for clinical and investigative science at Rockefeller University, New York.
The Italian report prompted them to analyze data from the phase 4, double-blind, randomized ObePso-S study investigating the effects of the IL-17 inhibitor secukinumab (Cosentyx) on systemic inflammatory markers and gene expression in psoriasis patients. The investigators demonstrated that IL-17–mediated inflammation in psoriasis patients was associated with increased expression of the angiotensin-converting enzyme 2 (ACE2) receptor in lesional skin, and that treatment with secukinumab dropped ACE2 expression to levels seen in nonlesional skin. Given that ACE2 is the chief portal of entry for SARS-CoV-2 and that IL-17 exerts systemic proinflammatory effects, it’s plausible that inhibition of IL-17–mediated inflammation via dampening of ACE2 expression in noncutaneous epithelia “could prove to be advantageous in patients with psoriasis who are at risk for SARS-CoV-2 infection,” according to Dr. Krueger and his coinvestigators in the Journal of Allergy and Clinical Immunology.
Dr. Damiani and Dr. Fougerousse reported having no financial conflicts regarding their studies. The secukinumab/ACE2 receptor study was funded by Novartis.
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