SARS-CoV-2 viral antigen found in non-lung tissue of recovering patients

A team of Singaporean researchers, led by Dr. Joe Yeong and Professor Tony Kiat Hon Lim, reported that SARS-CoV-2 ribonucleic acid (RNA), the genetic material of the virus, remains in the stool sample and gastrointestinal tract. Tissue of patients recovering from 2019 coronavirus disease (COVID-19).

Intestinal lesions of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are already known. However, detection of viral antigens in the “recovery” gastrointestinal and hepatic organs has not yet been reported.

COVID-19 was declared a pandemic by the World Health Organization (WHO) in March 2020. SARS-CoV-2 was first detected in Wuhan, China in late December 2019. Since then, it has infected more than 50 million people and killed 1.25 million people.

Rapid research into the disease is being conducted around the world to better understand the virus, find remedies or strategies, control its infection, and develop safe medical policies. Direct gastrointestinal infections and the resulting fecal-oral route of transmission are serious concerns for the condition of COVID-19.

In this regard, a Singapore research team investigated the presence of SARS-CoV-2 virus particles and SARS-CoV-2 specific immunity in intestinal and liver tissues.They recently reported their glorious discoveries medRxiv* Preprint paper.

Immunohistochemical staining of SARS-CoV-2 nucleocapsid protein in normal colon and liver tissue.

The study cohort consists of two COVID-19 patients-both were middle-aged men diagnosed with COVID-19 and recovered from it. Patient 1 underwent laparoscopic right hemicolectomy (for a malignant mass around a large colon).

Patient 2 had an important history of chronic hepatitis B virus-related cirrhosis and segment VII hepatocellular carcinoma (HCC). He underwent a curative resection of HCC.

Colon, ileum, appendix, And lymph node tissue was removed from patient 1 during surgery, and liver tissue was removed from patient 2.

Using immunohistochemistry, the researchers detected SARS-CoV-2 nucleocapsid in the intestinal and liver tissues of both patients. The SARS-CoV-2 nucleocapsid and the angiotensin converting enzyme 2 (ACE2) receptor were in close proximity.They also found SAR-CoV-2 Spike protein (Or S protein). However, the viral RNA detected by the reverse transcription-polymerase chain reaction (RT-PCR) test was not present in liver tissue, probably due to the long recovery period.

Although many postmortem studies have shown SARS-CoV-2 in a variety of organs, findings from patients with mild COVID-19 differ from these postmortem studies. Patients infected with COVID-19 may not represent the general population because they have a more severe course of illness. As in this case in the two patients here, these men suffered from a mild infection and recovered months before this study.

Researcher ran ex vivo A peptide stimulation assay containing a cocktail of viral nucleocapsides, spikes, and membrane proteins to examine SARS-CoV-2 specific immunity in the tissues of recovered patients. The results indicate that SARS-CoV-2 specific CD38 + granzyme B + CD4 + T cells were induced, and SARS-CoV-2 specific memory T cells are maintained in both tissue and blood. It suggests that there is a possibility. This discovery is the first report.

SARS-CoV-2 virus particles have been detected in the respiratory tract of patients recovered from COVID-19, raising concerns about potential viral reservoirs.

“In summary, it seems that SARS-CoV-2 can be cleared later in the gastrointestinal tract than in the respiratory tract, so negative. Nasopharyngeal swab Results do not necessarily indicate complete viral clearance from the body. “

This study is the first report of SARS-CoV-2 antigen detection in non-lung tissue of clinically recovered COVID-19 patients. Conducted in non-postmortem situations, it presents an important preliminary study that sheds light on the necessary attention around patients who have recovered with COVID-19 and disease management plans. Further investigation is needed to test whether a viral antigen is infectious-its ability and stability in the environment, and abundance of shedding.

“Care should be taken when dealing with tissues from patients with a recent history of COVID-19, especially during aerosol production procedures such as ultrasound anatomical surgery.”

Little is known about the prevalence and prognosis of SARS-CoV-2 virus antigens involved in daily life. This initial evidence of the presence of RNA particles in recovered COVID-19 patients may affect public health policies regarding the transmission of COVID-19 infections other than the respiratory pathway.

*Important Notices

medRxiv publishes unpeer-reviewed preliminary scientific reports and should not be considered definitive, guide clinical / health-related behaviors, or be treated as established information.