Scientists are using a new genetic technique to screen more than 3,000 proteins and identify 6 that underlie an increased risk of severe COVID-19 and 8 that appear to contribute to protection once morest severe forms of COVID-19. This is how the ABO protein, which determines blood groups, is identified as having a causal link with the risk of developing severe COVID-19.
Blood type might therefore play a determining role in the development of COVID
Lead author Dr Alish Palmos from the Institute of Psychiatry, Psychology and Neuroscience at King’s College explains: “We use a purely genetic and computational approach to study a large number of blood proteins and we identify a handful as having causal links with the development of severe forms of COVID-19.
Mendelian randomization, a method for comparing causal relationships between different risk factors and health outcomes, uses large genetic data sets, and can assess the relationship between exposure-related genetic variants (in this case, high levels of individual blood proteins and genetic variants linked to the course of severe COVID-19 disease). Here, the study considered 2 levels of COVID-19 severity: hospitalization and respiratory support, or death. The analysis thus identifies:
- 6 proteins causally linked to increased risk of hospitalization or respiratory support as well as death from COVID-19;
- 8 protective proteins once morest hospitalization or respiratory assistance and death;
- a “distinction” between the types of proteins linked to hospitalization and those linked to respiratory assistance and death, which suggests that different mechanisms are at work in these 2 stages of disease severity ;
- the enzyme (ABO) that determines blood group appears to be causally associated with both an increased risk of hospitalization and the need for respiratory support. These different data, combined with those of previous showing that the proportion of group A is higher in subjects positive for COVID-19, suggest that
- blood group A is a good “candidate” group for future follow-up studies.
Dr Christopher Hübel of King’s College London, co-author of the study summarizes this result: “The ABO enzyme helps determine an individual’s blood type and is linked to both the risk of hospitalization and the need for respiratory support or death. Our study does not link specific blood type to risk of severe COVID-19, but as previous research has shown that the incidence of COVID infection is higher in people with type A, this suggests that blood type A is probably more vulnerable. We’ll have to figure out why.”
A new step towards novel therapeutic targets: Identifying these proteins and assessing how they relate to disease can help understand the underlying mechanisms and identify new targets for drug development or repurposing.
- 3 adhesion molecules are also identified as causally linked to a reduced risk of hospitalization and the need for respiratory assistance. As these adhesion molecules mediate the interaction between immune cells and blood vessels, this is consistent with previous research suggesting that the late stage of COVID-19 also involves the endothelial walls of blood vessels.
By identifying this series of proteins, the research highlights, in an “original” way, a number of possible targets for treating severe COVID-19.
