Clinical and laboratory features of lupus patients with complicating pulmonary disease

The objective of this study was to determine the incidence of pulmonary involvement in patients with systemic lupus erythematosus (SLE) and to clarify the clinical and laboratory characteristics in SLE patients with various pulmonary involvements. A retrospective study (n = 137) revealed that the types of pulmonary involvement found in SLE patients were: pleuritis (9%), interstitial pneumonia (8%), pulmonary infarction (7%), pulmonary infection (4%), pulmonary hypertension (2%), restrictive dysfunction (28%) and decreased diffusion capacity (43%). The incidences of pericarditis (P < 0.01), arthralgia (P < 0.05) and hypoalbuminemia (P < 0.05) were significantly greater in patients with pleuritis than in those without, while in patients with interstitial pneumonia, the incidence of anti-SS-A antibody (P < 0.05) and sicca syndrome (P < 0.05) were significantly greater than in those without. A longitudinal follow-up study of patient groups with various pulmonary involvements revealed: 1. significant changes of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), lactate dehydrogenase (LDH) and thrombomodulin (TM) in patients with pleuritis, and 2. significant changes of WBC and LDH in patients with interstitial pneumonia. The increased ESR, CRP and TM levels during disease episodes suggest that the involvement of inflammatory processes is related to vasculitic events in the pathogenesis of lupus pleuritis. A higher incidence of anti-SS-A antibody in lupus patients with interstitial pneumonia suggests a potential role for this autoantibody in the pathogenesis of this complication.