Despite the increased risk of severe disease for transplant recipients, there have been few studies focused on the immune response of transplant recipients with COVID-19. But a new study, published in Nature Communications, found that transplant recipients demonstrated a distinct immune response compared to non-transplant recipients.
Patients with a solid organ transplant (SOT) are required to take numerous immunosuppressants to prevent rejection of their donated organ. But the medications also weaken the immune system, leaving patients more vulnerable to infections. As COVID-19 emerged, researchers from UCLA Health and UC San Francisco aimed to study the unique immunologic and viral microbial biomarkers, and the clinical outcomes of patients with SOT who were hospitalized with COVID-19.
“It’s an exciting study because we were focused on a vulnerable patient group,” said Dr. Elaine Reed, professor of pathology and laboratory medicine in the Division of Immunogenetics at the David Geffen School of Medicine at UCLA and co-senior author of the paper.
To conduct the study, the researchers investigated 86 SOT patients and 172 matched controls: COVID patients who had not received a transplant. The patients were selected from a multicenter cohort study funded by the National Institutes of Health that tracks the immune responses of people hospitalized with COVID-19. These individuals underwent multi-omic and computational analysis, meaning their gene, protein, and immune activity was examined, along with the viral abundance and the airway microbiome in their bodies.
The study found that patients with SOT had an activated immune response and amplified inflammatory signaling. “We were initially very surprised by the findings because these patients have suppressed immune systems,” said Dr. Chaz Langelier, an associate professor of medicine in UCSF’s Division of Infectious Diseases and co-senior author of the paper. “Interestingly, we found that this amplified inflammatory signal didn’t change that much between mild and severe COVID-19 in the SOT recipients, in contrast to the control group which experienced a dramatic increase in the levels of inflammatory cytokines during severe disease – the so-called ‘cytokine storm.’” The patients with SOT also had a higher abundance of COVID-19 in their nasal cavity and lower antibody levels.
Beyond the biological markers, the study found that the patients with SOT did not have higher mortality rates compared to the matched controls. “This may be because of their distinct immune state of lacking gene and protein expression linked to severe COVID-19,” said Reed. “Moving forward, we can leverage this information to better activate the immune system against infectious diseases for this patient group.”
“We hope that these results will lead to new and better infectious disease treatment and prognostic approaches in patients who have received organ transplants,” Langelier added.
