Liver transplanted patients who acquired COVID-19 recovered faster without serious inflammation while compared to the kidney and heart transplant recipients, moreover, some of the liver transplanted patients did even better than the non-transplant patients, finds a study conducted at Hospital das Clínicas (HC), the hospital complex run by the University of São Paulo's Medical School (FM-USP) in Brazil.
A study published in the journal Transplantology reports that the researchers looked at COVID-19 progression in 39 solid organ transplant recipients, 25 of whom had received kidney transplants, and each heart and liver went to seven.
The findings were compared to data from a control group of 25 non-transplant COVID-19 patients who were matched for age and had no comorbidities. To track disease progression, all participants in the study were tested every day for biomarkers of SARS-CoV-2 infection. Organs received age and time since transplantation were used to divide the volunteers.
"A hypothesis that could explain this unequal progression of the disease among transplant patients relates to different amounts of immunosuppressants used to prevent organ rejection," Ricardo Wesley Alberca, first author of the article, told Agência FAPESP. Alberca has a postdoctoral scholarship from FAPESP.
Heart and kidney transplants require larger amounts of immunosuppressants needed for liver transplant patients, which are lesser compared to kidney and heart transplanted patients. "In light of this difference, besides the conclusion that not all transplant recipients respond to COVID-19 in the same manner, our study also points to a possibility of testing certain immunosuppressants to treat COVID-19 patients, whether or not they are transplant recipients," he said.
On the contrary, the possible link between the progression of COVID-19 among organ transplanted patients and a load of immune-suppressing medications is just a hypothesis that needs further investigation and study.
"These patients receive different immunosuppression treatments. Kidney and heart recipients receive a much larger amount of immunosuppressants than liver recipients. A clinical trial now being conducted by a group of researchers outside Brazil involves a very well-known immunosuppression treatment administered to liver recipients," he said.
The FM-USP researcher team assumes that less strong doses of immune-suppressing medications for SARS-CoV-2 can give positive results."This has yet to be investigated, but in theory, mild immunosuppression might be beneficial in cases of immune system hyperactivation, such as the so-called cytokine storm typical of severe COVID-19, where the organism responds exaggeratedly, potentially leading to death," he said.
Patients with comorbidities, the elderly, and transplant recipients have all been considered high-risk groups for severe COVID-19 since the outbreak began. Transplant recipients, on the other hand, are a distinct subset of the general population, and the limited research done on them hasn't compared the effects of the disease in recipients of various organs.
In the first half of 2020, the FM-USP study will be part of a larger epidemiological survey of more than 500 COVID-19 patients treated at the HC. FAPESP and CAPES, the Ministry of Education's Coordination for the Improvement of Higher Education Personnel, are both supporting it.
The researchers intend to look into SARS-CoV-2 infection rates in the subjects who are undergoing treatment with prescribed immunosuppressants as well as the immunomodulators, like the patients with atopic dermatitis, psoriasis, or HIV/AIDS.
We're looking at how different comorbidities affect the immune response to COVID-19, and we hope that the research will lead to a better understanding of the disease's immunopathogenesis concerning diseases or conditions that require immunosuppressive treatment, such as organ transplants," said Maria Notomi Sato, an FM-USP professor.