Covid-19 patients have differing immune responses that lead to disease outcomes ranging from asymptomatic SARS-CoV-2 infection to death.After examining the blood samples from nearly 200 Covid-19 patients, researchers have uncovered underlying metabolic changes that regulate how immune cells react to the disease.These changes are associated with disease severity and could be used to predict patient survival. The findings were published in the journal Nature Biotechnology."We analysed thousands of biological markers linked to metabolic pathways that underlie the immune system and found some clues as to what immune-metabolic changes may be pivotal in severe disease,"said Jihoon Lee, a graduate student at Fred Hutchinson Cancer Research Center."Our hope is that these observations of immune function will help others piece together the body's response to Covid-19," Lee added.
The researchers collected 374 blood samples -- two draws per patient during the first week after being diagnosed with SARS-CoV-2 infection -- and analysed their plasma and single immune cells.The analysis included 1,387 genes involved in metabolic pathways and 1,050 plasma metabolites.In plasma samples, the team found that increased Covid-19 severity is associated with metabolite alterations, suggesting increased immune-related activity.Furthermore, through single-cell sequencing, researchers found that each major immune cell type has a distinct metabolic signature."We have found metabolic reprogramming that is highly specific to individual immune cell classes (eg 'killer' CD8+ T cells, 'helper' CD4+ T cells, antibody-secreting B cells, etc) and even cell subtypes, and the complex metabolic reprogramming of the immune system is associated with the plasma global metabolome and are predictive of disease severity and even patient death," said Dr Yapeng Su, a research scientist at Institute for Systems Biology."This work provides significant insights for developing more effective treatments against Covid-19. It also represents a major technological hurdle," the researchers noted.