Correlation of high-resolution computed tomography and immunological bronchoalveolar lavage in interstitial lung disease at the onset of inflammatory rheumatic diseases: implications for diagnosis and therapeutic strategies

Inflammatory rheumatic diseases (IRD) are often associated with interstitial lung disease (ILD). The aim of the present study was to establish a correlation between the findings on HRCT and the immunological bronchoalveolar lavage (BAL). The study included 74 patients with newly diagnosed IRD and evidence of ILD on HRCT with the following pattern: ground-glass opacities (GGO), non-specific interstitial pneumonia (NSIP) and usual interstitial pneumonia (UIP). Patients with other HRCT pattern were excluded. No patient received any immunosuppressive therapy. In addition to HRCT, immunological BAL was performed and the American Thoracic Society clinical practice guideline were used to define BAL patterns (lymphocytic cellular pattern, neutrophilic cellular pattern, eosinophilic cellular pattern and unspecified pattern). The main HRCT patterns were NSIP (47.3%), GGO (33.8%), and UIP (18.9%). BAL patterns showed the following distribution: 41.9% lymphocytic cellular pattern, 23.0% neutrophilic cellular pattern, 18.9% eosinophilic cellular pattern, and 16.2% unspecific cellular pattern. Placing these data in the context of the HRCT findings, the lymphocytic cellular BAL pattern (48%) was most commonly BAL pattern associated with GGO pattern in HRCT, whereas neutrophilic and lymphocytic cellular BAL patterns were the dominant feature in NSIP and UIP. In patients with new-onset IRD and ILD, inflammatory pulmonary changes are predominate, reflected by GGO on HRCT and a mainly lymphocytic cell profile in the immunological BAL. In NSIP or UIP on HRCT, the percentages of lymphocytes and neutrophils were higher in BAL fluid, representing a fibrotic component in addition to the inflammation. Consequently, patients with evidence of GGO on HRCT should primarily be treated with anti-inflammatory/immunosuppressive therapy, whereas in patients with NSIP and UIP a combination of anti-inflammatory and anti-fibrotic agents would be the appropriate treatment.