COMMENT: DPP9 enzyme deficit could be key to severe COVID-19 infection

The first study of human gene associations with severe COVID-19 has just been accepted for publication in the highly prestigious journal ‘Nature’.

In the study, led by Dr Kenneth Baillie at the University of Edinburgh, five genetic sequences associated with severe COVID-19 illness were found. The sequences are known to be involved with inflammation and the body’s defence mechanisms.

Professor Mark Gorrell, Head of the Centenary Institute’s Liver Enzymes in Metabolism and Inflammation Program, comments, “I’m particularly interested in this study because one of the proteins identified by this large UK consortium as being associated with severe COVID is an enzyme that we discovered and which we are continuing to investigate at the Centenary Institute, called dipeptidyl peptidase 9 or DPP9.”

“DPP9, an enzyme encoded by the DPP9 gene, has many functions including several related to immune responses and cell growth and cell movement. Potentially most significant to COVID-19, in which inflammation can get out of control, is that DPP9 restrains inflammation. So, we think that possibly a deficit in DPP9 may be exacerbating inflammation.”

Professor Gorrell says that his ongoing work with DPP9 and this Nature paper show that few people have a deficit in DPP9.

“This may be one of the reasons as to why many people experience no symptoms from the illness, while a small minority of others become critically ill.”

Professor Gorrell and his group first discovered the enzyme DPP9 in 1999.