CT scan report is showing multiple lymph nodes swelling extensive mediastinal, bilateral hilar and supraclavicular lymphadenopathy. Multiple small bilateral lung nodules & small hypodensities in the spleen. As per lymph node excision biopsy report it's showing necrotizing granulomatous inflammation. TB-PCR and Genexpert MTB both are negative result. Patient is having dry cough, loss of appetite, excessive fatigue and no fever. What would be the suspected cause and direction to be followed?