In a patient with newly diagnosed with antisynthetase syndrome without clinical myositis who presents with organizing pneumonia and improves on high-dose corticosteroids, what factors should guide the selection of long-term immunosuppressive therapy?
Additionally, how common is diffuse hilar, axillary, or mediastinal lymphadenopathy seen in antisynthetase syndrome and can a reactive pattern on transbronchial biopsy reliably exclude alternative etiologies?