Science Sub-Journal: Reveals that OVERactivation of MAIT cells is associated with severe COVID-19.

Oct 6, 2020 /--- -- The new coronavirus SARS-CoV-2, which causes coronavirus disease (COVID-19) in 2019, is now wreaking havoc around the world.
in a new study, researchers from Sweden's Karolinska Institute found that an antibacterial T cell, called mucosal-related constant T cells (mucosal-associated invariant T cells, MAIT), was strongly activated in moderate to severe COVID-19 patients.
findings could help increase understanding of how our immune system responds to SARS-CoV-2 infections.
study was published in the September 28, 2020 issue of the journal Science Immunology under the title "MAIT cell activation and dynamics associated with COVID-19 disease severity".
significant decline in MAIT cells in the blood of patients with COVID-19, pictured is Science Immunology, 2020, doi:10.1126/sciimmunol.abe1670.
"In order to find a potential treatment for COVID-19, it is important to learn more about how our immune system responds, which in some cases can lead to disease exacerbation," said Johan Sandberg, co-author of the paper and a professor in the Department of Medicine at the Karolinska Institute.
"T cells are white blood cells that specifically identify infected cells and are an important part of the immune system.
1 to 5 percent of T-cells in healthy people's blood are made up of MAIT cells, which are mainly used to control bacteria, but can also be recruited by the immune system to fight some viral infections.
study, the researchers hope to find out what role MAIT cells play in the onset of COVID-19 disease.
they studied the presence and characteristics of MAIT cells in blood samples from 24 moderate to severe COVID-19 patients treated at the Karolinska Institute Hospital and compared them with blood samples from 14 healthy controls and 45 COVID-19 rehabilitation patients.
four of the 24 patients died in hospital.
their results showed a sharp decline in the number of MAIT cells in the blood of moderate or severe COVID-19 patients, while the remaining circulating MAIT cells were highly activated, indicating that they were involved in an immune response to SARS-CoV-2.
pattern of reducing and activating MAIT cells in the blood is stronger than that of other T-cells.
the researchers also noted that inflammatory MAIT cells accumulate more in the airdoor in COVID-19 patients than in healthy people.
, these analyses suggest that the decrease in the number of MAIT cells in the blood of COVID-19 patients is at least partly due to their increased accumulation in the air, " Sandberg said.
, the researchers said, the number of MAIT cells in the blood recovered from COVID-19 recovered at least partially within a few weeks of being the disease, which may be important for controlling bacterial infections in COVID-19 patients.
note that MAIT cells tend to be extremely active and the expression of the subject CXCR3 is lower in patients who die than in patients who survive COVID-19.
, "Our results suggest that MAIT cells are highly involved in the immune response to COVID-19."
possible explanation is that the properties of MAIT cells make them involved in systemic immune responses and local immune responses in the airways at an early stage, so they are recruited into the airways by inflammatory signals.
, they are likely to rapidly promote a congenital immune response to the coronavirus.
in some COVID-19 patients, MAIT cells are overactive, which is associated with severe COVID-19.
(bioon.com) Reference: 1. Jean-Baptiste Gorin et al. MAIT cell activation and dynamics associated with COVID-19 disease severity. Science Immunology, 2020, doi:10.1126/sciimmunol.abe1670.2.Strong activation of anti-bic T cells linked to severe COVID-19.