Part A. Reports (16 point/each; total 80 points) Please make a report on each of the following five topics: hypersensitivity, autoimmune diseases, immunodeficiency, tumor immunology and transplantation immunology. Each report should include at least the following points: definition of disease, etiology, clinical symptoms, and immune mechanism and immunotherapy involved in the disease. Part B. Question and answer (20 points) Please describe the contributions of immunology to the diagnosis, treatment and prevention of the COVID-19.