Usual interstitial pneumonia: idiopathic pulmonary fibrosis versus collagen vascular diseases.

BACKGROUND

Bronchoalveolar lavage fluid (BALF) lymphocytosis was found in patients with usual interstitial pneumonia (UIP) associated with collagen vascular diseases (CVD) other than diffuse systemic sclerosis (SSc), but it was not found in patients with idiopathic pulmonary fibrosis (IPF), a disease histologically diagnosed as UIP. This difference could be partly due to variations of UIP spectrums between IPF and interstitial pneumonia associated with CVD.

METHODS

We scored histopathological findings of lung specimens obtained from 31 cases (16 IPF, 9 CVD other than SSc and 6 SSc) using a semiquantitative scoring method. All cases were diagnosed as UIP by surgical lung biopsy. None of the patients were current smokers.

RESULTS

Compared with IPF and SSc cases, CVD patients without SSc presented decreased scores of fibrosis (p < 0.01) and alveolar space cellularity (severity, p < 0.05). Lymphocytes were mainly localized in the alveolar walls and the majority of cells in the alveolar spaces were macrophages. On the other hand, other scores such as cellularity and alveolar wall cell infiltrate did not vary among these three groups.

CONCLUSION

Fewer macrophages in the alveolar spaces and a decrease in the degree of fibrosis may contribute to BALF lymphocytosis more in patients with UIP/CVD non-SSc than in patients with IPF/UIP and UIP-SSc.