Immune suppressants might play a role in the early treatment of Covid-19, one expert has suggested amid several studies highlighting the body’s over-reaction to the virus.
One study, at the University of South California, USA, found an interaction between the innate and adaptive immune responses, triggered by the "slow" disease progression of Covid-19. They reported their findings in the Journal of Medical Virology.
Professor Wieming Yuan, an immunologist at the University’s School of Medicine, said: "The danger is, as the infection keeps going on, it will mobilise the whole of the adaptive immune response with its multiple layers.
"This longer duration of viral activity may lead to an overreaction of the immune system, called a cytokine storm, which kills healthy cells, causing tissue damage."
Fellow researcher Dr Sean Du said: "Based on the results of the mathematical modelling, we proposed a counterintuitive idea that a short regimen of a proper immunosuppressant drug applied early in the disease process may improve a patient’s outcome.
"With the right suppressive agent, we may be able to delay the adaptive immune response and prevent it from interfering with the innate immune response, which enables faster elimination of the virus and the infected cells."
* A study from China reports in detail the impact of cytokine "storms" on patients. Researchers reported a significantly reduced number of T cells in infected patients – with counts being lowest among the most severely ill patients.
The researchers compared 522 treated in Wuhan earlier this year with 40 health people. Their findings were reported in Frontiers of Medicine.
They report that T cells that survived were "exhausted".
Dr Yongwen Chen, of Third Military Medical University, China, said: "We should pay more attention to T cell counts and their function, rather than respiratory function of patients."
* British neurologists have raised new concerns about how the virus causes blood clotting.
Doctors at the National Hospital for Neurology and Neurosurgery, London, call for early testing for D-dimer in Covid-19 patients in a report published in the Journal of Neurology, Neurosurgery, and Psychiatry.
Their conclusions come from a study of six successive patients with acute ischaemic stroke and virus infection. In five cases stroke occurred at least eight days after onset of symptoms.
Mathematical Modeling of Interaction between Innate and Adaptive Immune Responses in COVID?19 and Implications for Viral Pathogenesis. Journal of Medical Virology 1 May 2020
https://onlinelibrary.wiley.com/doi/abs/10.1002/jmv.25866
Reduction and Functional Exhaustion of T Cells in Patients With Coronavirus Disease 2019 (COVID-19). Frontiers in Immunology 1 May 2020
https://www.frontiersin.org/articles/10.3389/fimmu.2020.00827/full
Characteristics of ischaemic stroke associated with COVID-19
Journal of Neurology, Neurosurgery, and Psychiatry 30 April 2020
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