You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

Acute graft-versus-host disease (aGVHD) is a rare complication after liver transplantation that characterized by high mortality. We presented a case of aGVHD after orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC). The patient suffered from fever, oral ulcer, rashes and diarrhea and had a co-infection with Cytomegalovirus (CMV). Short tandem repeat (STR) analysis for cluster of differentiation (CD3) cells and skin biopsy indicated aGVHD. His regimens included high dose of steroids, ruxolitinib, basiliximab, local liver radiotherapy and antibiotics prophylaxis, with the withdrawal of tacrolimus and MMF. Unfortunately, he developed an acute rejection followed by cytomegalovirus infection and lung infection. Soon afterwards he was sent to "isolation ward" due to high suspicion for clinical coronavirus disease 2019 (COVID-19). Fortunately, He was excluded from COVID-19 after nucleic acid and antibody tests. Though closely contact with other COVID-19 patients for a month, the patient was not affected with COVID-19 through his careful protective measures. Finally, the patient recovered after antiviral and antifungal treatment. To our knowledge, this is the first case report of a patient recovered from aGVHD as a close contact.
["Case Report"]