Background Persistence of SARS-CoV-2 virus particles in recovered COVID-19 patients remains a challenge as we continue to fight the ongoing pandemic. For instance, despite three negative consecutive nasopharyngeal swab PCR tests, residual SARS-CoV-2 was reported in the lungs of a deceased patient.1 Moreover, viral RNA could also be detected in rectal tissues that were obtained during incubation period.2 To date, there is no data regarding residual viral particles present in tissues from recovered COVID-19 patients. Hereby, we reported our findings of SARS-CoV-2 viral antigen in liver tissues from a recovered COVID-19 patient. These findings raise concern for potential transmissibility in recovered individuals.
Methods A 49-year-old South Asian male diagnosed with COVID-19 in June 2020, with incidental discovery of hepatitis B virus (HBV)-associated R0 Grade 2 hepatocellular carcinoma (HCC), was consented for our study. He did not develop significant acute respiratory symptoms throughout the course of the disease. He underwent curative resection of HCC 85 days after being tested COVID-19 negative where his blood, normal tissue and tumour samples were obtained for further analysis (figure 1). We performed deep immunopathological profiling on the specimens using multiplex immunohistochemistry and 25-colour flow cytometry to study SARS-CoV-2-elicited immune response.
Results Multiplex immunohistochemistry detected SARS-CoV-2 nucleocapsid protein only in adjacent normal liver tissue but not within tumour core (figure 2). We also observed SARS-CoV-2 in some immune cells such as sinusoidal Kupffer cells (figure 2). Additionally, upon stimulation with SARS-CoV-2 peptides, we successfully elicited SARS-CoV-2-specific memory response which is distinct from the response upon challenge with HBV peptides. These findings were similar to our previous discovery in a patient with colorectal adenocarcinoma where we have shown viral antigen detection, validated with PCR to detect viral RNA, as well as the detection of SARS-CoV-2 memory-like T cells in situ (figure 2). Deep profiling of the samples is on-going with single-cell analysis and digital spatial profiling.
Conclusions We believe this is the first immune profiling report of the in situ tumour microenvironment in a cancer patient with COVID-19. Our findings demonstrated the presence of viral proteins in the liver despite negative swab test result and the ability to elicit ex vivo SARS-CoV-2-specific immune responses through peptide stimulation assays. We also detected same immune cell phenotypes in situ in the cancer tissues. Taken together, we propose caution when handling tissues from patients who have a recent history of COVID-19, particularly during aerosol-generating procedures such as ultrasonic dissection surgery.
Ethics Approval This study was approved by Centralised Institutional Review Board of SingHealth, approval number 2019/2653.
Consent Written informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.
Yao XH, He ZC, Li TY, Zhang HR, Wang Y, Mou H, et al. Pathological evidence for residual SARS-CoV-2 in pulmonary tissues of a ready-for-discharge patient. Cell Res 2020;30(6):541-3.
Qian Q, Fan L, Liu W, Li J, Yue J, Wang M, et al. Direct evidence of active SARS-CoV-2 replication in the intestine. Clin Infect Dis 2020.
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