Usual Interstitial Pneumonia: Idiopathic Pulmonary Fibrosis versus Collagen Vascular Diseases

Abstract

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.

Cellular and Humoral Autoreactivity in Idiopathic Pulmonary Fibrosis

“…However, multiple investigations also demonstrate mononuclear collections (including activated effector T cells) are unmistakably present in IPF lungs (1, 26, 27, 36 -39). Moreover, similar or even lesser degrees of T cell infiltration are frequently noted in other adaptive immune diseases, including lung allograft rejection (40) and various autoimmune syndromes (1,36,37,(41)(42)(43)(44), particularly in late fibrotic stages.…”

Progression of Fibrosis in Usual Interstitial Pneumonia: Serial Evaluation of the Native Lung after Single Lung Transplantation

“…However, with the use of finer classified scores we seemed to lose improved simplicity and reliability in the assessment of the FS and GGS. It is conceivable that the ground-glass opacities do not always represent cellular inflammation in the IPF population [32]. Nagao et al [32 ]demonstrated that the UIP histology showed a greater paucity of bronchoalveolar lavage fluid lymphocytosis in the IPF patient group than in the UIP patient group with associated collagen vascular disease.…”

“…It is conceivable that the ground-glass opacities do not always represent cellular inflammation in the IPF population [32]. Nagao et al [32 ]demonstrated that the UIP histology showed a greater paucity of bronchoalveolar lavage fluid lymphocytosis in the IPF patient group than in the UIP patient group with associated collagen vascular disease. In addition, most IPF patients in our group presented at later stages of the disease with advanced fibrotic changes, whereas ground-glass opacity was expected to be minimal.…”

Role of Broncoalveolar Lavage in Diagnosis

“…The BAL findings are also somewhat different from IPF. The general pattern is increased neutrophils, with or without eosinophils, but increased lymphocytes are more commonly seen than in IPF [31]. In general, BAL seems to have a limited value in the diagnosis of CVD affecting the lungs because the BAL profile is very nonspecific.…”