A 25-year-old patient complains of heavy gingival hemorrhages, pain in the oral cavity, weakness, fatigue, fever up to 38°C. These presentations appeared a week ago. Objectively: the patient is pale, adynamic. Examination of the oral mucosa reveals multiple hemorrhages, friable gums, necrotic areas on the tops of gingival papillae, as well as enlarged, soft, painless lymph nodes. The oral mucosal lesion can be a symptom of the following disease: