High acute phase protein levels correlate with pulmonary and skin involvement in patients with diffuse systemic sclerosis

OBJECTIVE: This study was performed to evaluate the serum amyloid A (SAA) and C-reactive protein (CRP) levels in patients with diffuse systemic sclerosis (dSSc) in relation to a control group, disease duration, and skin and pulmonary involvement. METHODS: This case-control study included 18 patients with early dSSc, 15 patients with late dSSc, and 15 healthy controls. The SAA and CRP levels, modified Rodnan skin score (mRSS), and diffusing capacity of the lungs for carbon monoxide (DLCO) were determined in all patients. RESULTS: The SAA and CRP levels were significantly higher in patients with early and late dSSc than in healthy controls. The frequency of detection of elevated SAA and CRP levels was approximately 66% and 85%, respectively. A significant correlation was found between the SAA and CRP levels in patients with dSSc. The SAA and CRP levels were inversely correlated with DLCO. The CRP level was positively correlated with the mRSS. CONCLUSIONS: High SAA and CRP levels could serve as biomarkers for pulmonary involvement. The serum CRP level accurately reflects the extension of skin thickening in patients with dSSc.