A 7-year-old child became ill again 2 weeks after a case of tonsillitis. There are the following complaints: temperature rise up to 38°C, hemorrhagic rash on the extremities, enlargement of the ankle joints. Blood test: hemoglobin is 120 g/l, platelets are 170 × 109/l, ESR is 30 mm/hour. Urine test: proteinuria up to 0,7 g/l, cylinders - 5-6 in the field of vision, erythrocytes - 8-10 in the field of vision. What mechanism of hemorrhagic syndrome is present in the given case?