Covid and Immunity of High Risk Patients
What’s in the news?
Studies have found why older people and people with underlying conditions at particular risk have severe Covid-19.
Findings of the study
- While these risk groups produce greater quantities of the immune cell known as ‘T-helper cells’, their T-helper cells show impaired function.
- Advancing age and overall comorbidity scores were linked to a decrease in the proportion of cells producing an important messenger molecule.
- This stimulates other components of the immune response. In patients with risk factors, some of the SARS-CoV-2-specific T cells no longer function properly.
- The researchers were able to show a correlation between the frequency of virus-specific T-helper cells and the patients’ age.
- The same positive correlation was also found in relation to the ‘Comorbidity Index’, a measure expressing the severity of 19 different underlying medical conditions. The higher the patient’s Comorbidity Index, the higher the number of SARS-CoV-2-specific T-helper cells in their blood.
- A protein called PD-1 is known to act as a molecular ‘brake’ on the immune system. It regulates the immune response so as to prevent the immune system attacking the body.
- The researchers showed that the virus-specific T-helper cells produced more PD-1 in patients with acute infection, than in those with milder symptoms.
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