Plasma polymorphonuclear neutrophil elastase in systemic sclerosis: clinical correlative study

To measure the plasma level, of polymorphonuclear neutrophil [PMN] elastase in patients with systemic sclerosis [SSc] and to study its relation to interstitial pulmonary fibrosis, extent of skin sclerosis, and other clinical manifestations of the disease. Seventeen patients with SSc [7 diffuse SSc [dSSc] and 10 limited SSc [lSSc]] and 13 controls were included. The degree of skin involvement was quantified by modified Rodnan skin thickness score [mRSS]. Pulmonary involvement was assessed in all patients by high resolution computerized tomography [HRCT] and pulmonary function tests [PET]. Plasma PMN elastase was measured in all patients and controls. There was a significant increase of plasma PMN elastase levels in SSc patients compared to controls. Elevated plasma PMN elastase levels were observed in 47.05% of all SSc patients especially in dSSc subtype and were significantly associated with the more frequent presence of arthritis [P=0.049]. Pulmonary fibrosis was detected in 82.35% of SSc patients by HRCT and restrictive lung disease, defined by FVC <80%, was detected in 70.58% of patients. Ground glass opacification [GGO] was detected more frequently in SSc patients with elevated PMN elastase levels compared to patients with normal levels. The presence elevated plasma PMN elastase in SSc patients had a positive predictive value PV] of 83.3% in detecting early interstitial lung fibrosis. Plasma PMN elastase correlated with CRP but not with the extent of skin involvement or PFT results. Elevated PMN elastase may be used as a simple screening test to predict early interstitial pulmonary fibrosis in patients with SSc