Serum B cell-activating factor (BAFF) level in connective tissue disease associated interstitial lung disease.

BACKGROUND: Interstitial lung diseases (ILDs) are common in patients with connective tissue diseases (CTDs). Although the diagnosis of an underlying CTD in ILD (CTD-ILD) affects both prognosis and treatment, it is sometimes difficult to distinguish CTD-ILD from chronic fibrosing interstitial pneumonia (CFIP). B cell-activating factor belonging to the tumour necrosis factor family (BAFF) plays a crucial role in B cell development, survival, and antibody production. METHODS: We examined serum levels of BAFF, surfactant protein D (SP-D), and Krebs von den Lungen-6 (KL-6) in 33 patients with CTD-ILD, 16 patients with undifferentiated CTD-ILD, 19 patients with CFIP, and 26 healthy volunteers. And we analysed the relationship between serum BAFF levels and pulmonary function, as well as the expression of BAFF in the lung tissue of patients with CTD-ILD. RESULTS: Serum levels of BAFF were significantly higher in CTD-ILD patients compared to healthy subjects and CFIP patients. However, there were no significant differences in serum levels of SP-D and KL-6. Furthermore, serum BAFF levels in CTD-ILD patients were inversely correlated with pulmonary function. BAFF was strongly expressed in the lungs of CTD-ILD patients, but weakly in normal lungs. DISCUSSION: This is the first study to demonstrate that serum BAFF levels were significantly higher in CTD-ILD patients compared to healthy subjects and CFIP patients. Furthermore, serum BAFF levels were correlated with pulmonary function. We consider that serum BAFF levels in patients with CTD-ILD reflect the presence of ILDs disease activity and severity. CONCLUSION: These finding suggest that BAFF may be a useful marker for distinguishing CTD-ILD from CFIP.

Validation of a COPD screening questionnaire and establishment of diagnostic cut-points in a Japanese general population: the Hisayama study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is highly prevalent worldwide. COPD is a treatable disease and it is important to identify COPD subjects, highlighting the need for an efficient screening measure. Although the COPD screening questionnaire (COPD Population Screener, COPD-PS) was developed as a screening tool, its validity is not clear in population-based studies. This study determines the validity of the COPD-PS in the general Japanese population. METHODS: All registered residents living in the town of Hisayama aged above 40 were solicited to participate in a health check-up in 2012. All subjects aged 40-79 without physician-diagnosed asthma or lung resection were recruited, and 2357 subjects with the COPD-PS recorded and valid spirometry measurements were analyzed. Persistent airflow obstruction (AO) was defined by post-bronchodilator FEV1/FVC < 0.7. The sensitivity and specificity of the COPD-PS score for identifying AO was assessed by logistic regression analysis. RESULTS: The prevalence of AO in this population was 6.5%. The overall area under the receiver operating characteristic (ROC) curve for the continuous COPD-PS score was 0.748. A cut-point of 4-points is recommended, resulting in a sensitivity of 67.1% and specificity of 72.9% with an area under the ROC curve of 0.70. The positive predictive value was 14.6% and negative predictive value was 97.0%. CONCLUSIONS: The COPD-PS appears to be an adequate measure for large scale screening of possible airflow obstruction requiring further testing with spirometry.

The elevation of serum napsin A in idiopathic pulmonary fibrosis, compared with KL-6, surfactant protein-A and surfactant protein-D.

BACKGROUND: Napsin A, an aspartic protease, is mainly expressed in alveolar type-II cells and renal proximal tubules and is a putative immunohistochemical marker for pulmonary adenocarcinomas. This study sought to determine whether napsin A could be measured in the serum to evaluate its relationship to idiopathic pulmonary fibrosis (IPF) and determine whether renal dysfunction might affect serum napsin A levels. METHODS: Serum levels of napsin A were measured in 20 patients with IPF, 34 patients with lung primary adenocarcinoma, 12 patients with kidney diseases, and 20 healthy volunteers. Surfactant protein (SP)-A, SP-D, and Krebs von den Lungen-6 (KL-6) levels in serum and pulmonary function tests were also evaluated in IPF patients. RESULTS: Circulating levels of napsin A were increased in patients with IPF, as compared with healthy controls, and they correlated with the severity of disease. Moreover, the serum napsin A levels were not elevated in patients with pulmonary adenocarcinoma or renal dysfunction. The distinguishing point between IPF and the controls was that the area under the receiver operating characteristic curve (ROC) of napsin A was larger than that of KL-6, SP-A, or SP-D. CONCLUSION: These findings suggest that serum napsin A may be a candidate biomarker for IPF.