HIV Pathology

A 38-year-old man from Mumbai presents with a 3-week history of progressive dyspnea, fever, and dry cough. He reports unprotected sexual contact 18 months ago. On examination, he is tachypneic (respiratory rate 28/min) and oxygen saturation is 88% on room air. Chest X-ray shows bilateral interstitial infiltrates. CD4+ T-cell count is 85 cells/μL. Sputum examination is negative for acid-fast bacilli. Chest CT shows ground-glass opacities. Bronchoalveolar lavage fluid is positive for Pneumocystis jirovecii cysts on silver stain. What is the primary pathophysiologic mechanism underlying this opportunistic infection in this patient?

A 42-year-old woman from Delhi with a known CD4+ count of 120 cells/μL presents with a 2-week history of progressive headache, fever, and neck stiffness. Lumbar puncture shows clear cerebrospinal fluid (CSF) with elevated protein (180 mg/dL), normal glucose (48 mg/dL with simultaneous blood glucose 95 mg/dL), and no cells. CSF India ink stain is positive. Blood cultures are negative. What is the pathophysiologic basis for the CSF abnormalities in this patient's condition?

Which CD4+ T cell count threshold defines the transition from asymptomatic HIV infection to AIDS in a patient without opportunistic infections?

Which HIV protein is responsible for binding to the CD4 receptor on target cells, and what is its molecular weight?