A 32-year-old male from Delhi presents with a 3-month history of productive cough with blood-tinged sputum, fever in the evenings, and night sweats drenching his clothes. On examination, he is cachectic with a body mass index of 18 kg/m². Chest X-ray shows a cavitary lesion in the right upper lobe with surrounding consolidation. Sputum smear microscopy is positive for acid-fast bacilli (AFB). Histopathology of a lung biopsy specimen shows caseating granulomas with central acellular necrosis surrounded by epithelioid histiocytes and Langhans giant cells. Which of the following pathological features is MOST characteristic of the granulomatous response in tuberculosis?