title: The differing patterns of subclinical pulmonary involvement in connective tissue diseases as shown by application of factor analysis.
abstract: To explore common patterns of interstitial lung disease (ILD) in symptomless patients with connective tissue disease (CTD), we applied factorial analysis to determine the relationship among the factors. A selected cohort of 71 non-smoking patients with a confirmed diagnosis of CTD [24 with primary Sjögren's syndrome (pSS), 21 with systemic sclerosis (SS), 20 with rheumatoid arthritis (RA) and six with polymyositis/ dermatomyositis (PM/DM)] were identified. The diagnostic techniques included pulmonary function tests, bronchoalveolar lavage (BAL), chest radiographs and high-resolution computed tomography (HRCT). Disease extent and severity were assessed by a radiological and HRCT grading system. Three factors, accounting for 67% of the total variance, were extracted. The first factor (disease duration, diffusing lung capacity, neutrophils and CD8+ T cells on BAL, radiographic score and HRCT reticular score), with the highest percentage of variance (36.5%), defines a fibrotic lung pattern. The second factor (17.9% of variance) identifies an inflammatory lung pattern (macrophages, lymphocytes and eosinophils on BAL and HRCT ground-glass score). The third factor (12.6% of variance) represents a ventilatory function pattern (forced vital capacity, total lung capacity and forced respiratory volume in 1 s). The negative correlation between the fibrotic lung pattern and ventilatory function pattern, but not with the inflammatory lung pattern, suggests the presence of a significant derangement of the alveolar structures. In conclusion, application of factor analysis reveals various lung disease patterns in patients with CTD that might have different prognostic implications.
authors.affiliation: Clinica Reumatologica, Università di Ancona, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Salaffi
authors.forename: P
authors.initials: P
authors.lastname: Manganelli
authors.forename: M
authors.initials: M
authors.lastname: Carotti
authors.forename: S
authors.initials: S
authors.lastname: Baldelli
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000276:immunology; D018893:Bronchoalveolar Lavage; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D003240:Connective Tissue Diseases / Q000150:complications* / Q000175:diagnosis; D003937:Diagnosis, Differential; D004804:Eosinophils / Q000473:pathology; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000175:diagnosis / Q000209:etiology*; D016131:Lymphocyte Subsets / Q000276:immunology / Q000473:pathology; D016676:Macrophages, Alveolar / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000473:pathology; D011379:Prognosis; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D015703:Antigens, CD