A 67-Year-Old Man Comes to the Physician Because of a 6-Month

A 67-year-old man comes to the physician because of a 6-month history of increasing shortness of breath on exertion, dry cough, and fatigue. He has night sweats and weight loss. Chest x-ray shows pulmonary infiltrates and an area of cavitation in the right upper lobe.  Sputum microscopy shows acid-fast bacilli.  Which of the following is the most accurate statement concerning this patient's pulmonary infection?

A) First exposure to the bacilli occurred recently
B) Healing of the lung lesion would result in Ghon complex formation
C) It originated from reactivation of an old infection
D) It was facilitated by low levels of protective antibodies
E) Negative tuberculin skin test would signify strong cell-mediated immunity