Diagnostic Utility of Bronchoalveolar Lavage Lymphocytosis in Patients with Interstitial Lung Diseases

Interstitial lung diseases (ILDs) are extremely challenging in terms of diagnosis. Extreme bronchoalveolar lavage (BAL) lymphocytosis is thought to strongly point towards the diagnosis of hypersensitivity pneumonitis (HP).Explore the range of different ILD that can present with BAL lymphocytosis, including cases of pronounced lymphocytosis and its diagnostic utility.Patients with ILD that were subjected to BAL were identified retrospectively from a cohort of consecutive patients.BAL lymphocytosis ≥20% was recorded in 106 patients (27%), while pronounced BAL lymphocytosis ≥40% was recorded in 49 patients (12.5%). The most common diagnoses in patients with BAL lymphocytosis ≥20% and ≥40%, were HP (32.1%), connective tissue disease (CTD)-ILD (26.4%), sarcoidosis (16%), and HP (38.8%), CTD-ILD (24.5%), sarcoidosis (14.3%), respectively.Neither the presence nor the degree of BAL lymphocytosis can point to a specific diagnosis.