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Abstract

We appreciate the reader’s interest in our study1Hu Y. Wang L.S. Wei Y.R. et al.Clinical characteristics of connective tissue disease-associated interstitial lung disease in 1,044 Chinese patients.Chest. 2016; 149: 201-208Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar and have prepared the following response to the reader’s questions. First, we used line immunoassay to detect autoantibodies. The kits for line immunoassay and enzyme-linked immunosorbent assay are all from HUMAN-IMTEC. The clinical application of the kits have been approved by the China Food and Drug Administration. All of the tests were conducted in the Department of Laboratory Medicine of Shanghai Pulmonary Hospital according to the kit manuals provided by the manufacturer. Second, an antinuclear antibody (ANA) test is included in our routine laboratory test to diagnose connective tissue disease (CTD). However, the ANA test is not specific for CTD. A positive ANA test does not confirm CTD, and a negative ANA test cannot exclude CTD. Therefore, we did not include the data of the ANA test result. In our study we analyzed the test results of the HUMEN-IMTEC diagnostic kits, which include a relatively full list of autoantibodies.1Hu Y. Wang L.S. Wei Y.R. et al.Clinical characteristics of connective tissue disease-associated interstitial lung disease in 1,044 Chinese patients.Chest. 2016; 149: 201-208Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar Third, clinical tests for anticitrullinated protein antibodies (ACPAs), such as anticyclic citrullinated peptide, antiperinuclear factor, and antikeratin antibody, are currently not available in our hospital. In addition, Jearn and Kim2Jearn L.H. Kim T.Y. Level of anticitrullinated peptide/protein antibody is not associated with lung diseases in rheumatoid arthritis.J Rheumatol. 2012; 39: 1493-1494Crossref PubMed Scopus (10) Google Scholar found that ACPA levels did not correlate with the presence of lung disease in patients with rheumatoid arthritis. Contrarily, Yin et al3Yin Y. Liang D. Zhao L. et al.Anti-cyclic citrullinated peptide antibody is associated with interstitial lung disease in patients with rheumatoid arthritis.PLoS One. 2014; 9: e92449Crossref PubMed Scopus (41) Google Scholar demonstrated that positive serum anticyclic citrullinated peptide 2 was associated with an increased risk of ILD in patients with rheumatoid arthritis. We will test ACPAs in our future studies. The positive rate for autoantibodies is usually very high in patients with confirmed rheumatic disease. In our study, patients who first presented with extrapulmonary symptoms and then exhibited pulmonary symptoms were diagnosed as having CTD-associated interstitial lung disease (CTD-ILD). The positive rate for autoantibodies in those patients was 80.2%,1Hu Y. Wang L.S. Wei Y.R. et al.Clinical characteristics of connective tissue disease-associated interstitial lung disease in 1,044 Chinese patients.Chest. 2016; 149: 201-208Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar which is close to the rate (98.1%) in the correspondence by Jearn and Kim.2Jearn L.H. Kim T.Y. Level of anticitrullinated peptide/protein antibody is not associated with lung diseases in rheumatoid arthritis.J Rheumatol. 2012; 39: 1493-1494Crossref PubMed Scopus (10) Google Scholar Patients with CTD-ILD treated in the Department of Respiratory Medicine of Shanghai Pulmonary Hospital were often originally admitted because of pulmonary disorders. At hospital admission, the clinical presentations of those patients were mainly pulmonary disorders, and systemic symptoms of CTD-ILD did not appear yet. Therefore, the positive rate for autoantibody in those patients at hospital admission was low. The 2015 European Respiratory Society/American Thoracic Society statement recommends that patients with ILD should be routinely tested for autoantibodies during follow-up.4Fischer A. Antoniou K.M. Brown K.K. et al.An official European Respiratory Society/American Thoracic Society research statement: interstitial pneumonia with autoimmune features.Eur Respir J. 2015; 46: 976-987Crossref PubMed Scopus (627) Google Scholar Indeed, we have been routinely testing autoantibodies in our patients at hospital admission and during follow-up. Clinical Characteristics of Connective Tissue Disease-Associated Interstitial Lung Disease in 1,044 Chinese PatientsCHESTVol. 149Issue 1PreviewBecause the prevalence of connective tissue disease (CTD)-associated interstitial lung disease (ILD; CTD-ILD) in China is unknown, we wanted to analyze the clinical characteristics of this disease in Chinese patients. Full-Text PDF Autoantibodies Are Already Found in Connective Tissue Disease-Associated Interstitial Lung DiseaseCHESTVol. 150Issue 3PreviewWe read with interest the article by Hu and colleagues in a recent issue of CHEST (January 2016).1 However, we noted several key omissions, which are subsequently discussed. Full-Text PDF