Scientists from the University of Manchester have discovered an alteration in the immune system of COVID-19 patients 6 months after hospitalisation, which could be linked to poorer health outcomes
The study, published in the journal Med, examines the impact of COVID-19 on the immune system and the association with long COVID after a patient has been discharged from the hospital.
The research team compiled the immune cell characteristics of over 80 convalescent patients recruited from Manchester hospitals between July and October 2020.
They found that changes to B cells that occur during the peak of COVID-19 hospitalisation were largely restored by 6 months of convalescence, however, changes to T cells persisted into COVID-19 convalescence.
Study author Dr Joanne Konkel from The University of Manchester said: “Our study details persistent immune alterations in previously hospitalised COVID-19 patients up to 6 months after hospital discharge. Significantly, we outline an immune signature associated with poorer clinical outcomes in convalescent patients.
“Association, however, is not a causation, and what we now want to understand is what other long COVID symptoms this signature could be associated with and whether it could be used to identify the patients that should be most closely followed after hospital discharge.”
The signature present in the group of patients with the poorer clinical outcome was characterised by the team as having high levels of cytotoxic T cells – which can destroy other cells – as well as elevated production of special types of proteins called type-1 cytokines.
Study author Dr Madhvi Menon from The University of Manchester said: “It remains to be established if these immune alterations are unique to COVID-19, or whether they are also observed following other severe respiratory infections.”
“Follow-up studies will determine whether this signature can provide a tool to identify acute COVID-19 patients at risk of Long COVID, enabling close monitoring and improved clinical management.”, said Dr Menon.
Study author Dr John Grainger from The University of Manchester and deputy Director of the Lydia Becker Institute said: “Given the vast numbers of previously infected individuals across the globe, it is vital to understand the impact of COVID-19 on the phenotype and functional potential of all immune cells.
“This will allow for better understanding of the long-term impacts of being hospitalised with COVID-19 on subsequent anti-pathogen or auto-inflammatory responses.”
Read the full study here.