Lung involvement in primary Sjogren's syndrome is mainly related to the small airway disease

Objective-To evaluate lung involvement in patients with primary Sjogren's s yndrome. Methods-Sixty one consecutive, nonsmoking patients, 58 women and three men, were evaluated clinically, physiologically, and radiologically. A bronchia l and/or transbronchial biopsy was performed on 13 of the patients. Physiol ogical data were compared with that of a control group of 53 healthy non-sm oking subjects matched for age and sex. Results-In 41% of the patients the main symptom was dry cough. Physiologica l studies revealed that the patients presented significantly lower expirato ry flow values (% pred) when compared with those of the control group: the forced expiratory volume in one second (FEV1) (mean (SD)) was 96% (16) v 11 1% (13) (p<0.0001), the maximal expiratory flow at the 50% of the vital cap acity (MEF50) was 72% (24) v 103% (17) (p<0.0001), and the maximal expirato ry flow at the 25% of the vital capacity (MEF25) was 49% (25) v 98% (20) (p <0.0001). No significant difference was noted for the carbon monoxide diffu sion value (% pred), between patients and controls. Blood gases were evalua ted in 44 patients: mild hypoxemia was observed, and the alveolo-arterial o xygen difference (P(A- a)o(2)) correlated significantly with MEF50 (r=0.35, p<0.01) and MEF25 (r=0.33, p<0.01) values. Chest radiography showed mild, interstitial-like changes in 27 patients while slightly increased markings were present in 21. High resolution computed tomography of the lungs was pe rformed in 32 patients (four with a normal chest radiograph, six with suspe cted interstitial pattern, 19 with apparent interstitial pattern, and three with hyperinflation) and revealed predominantly wall thickening at the seg mental bronchi. All positive findings by computed tomography derived from t he patients with abnormal chest radiographs. Transbronchial and/or endobron chial biopsy specimens in 10 of the 11 sufficient tissue samples revealed p eribronchial and/or peribronchiolar mononuclear inflammation, while interst itial inflammation coexisted in two patients. Conclusion-The airway epithelia seem to be the main target of the inflammat ory lesion of the lung in patients with primary Sjogren's syndrome. It seem s to be common, subclinically leading to obstructive small airway physiolog ical abnormalities.