Procollagen Type I and III Aminoterminal Propeptide Levels and Severity of Interstitial Lung Disease in Mexican Women With Progressive Systemic Sclerosis.

BACKGROUND Interstitial lung disease (ILD) is a frequent complication in progressive systemic sclerosis (SSc), being present in 25% to 90% of cases. OBJECTIVES To evaluate whether serum levels of procollagen typei and iii aminoterminal propeptide (PINP and PIIINP) correlate with severity and patterns of ILD in Mexican women with SSc. METHODS Thirty three SSc patients were assessed for disease characteristics and anti-topoisomerase antibodies (topoi), and also underwent pulmonary function tests and high-resolution computed tomography (HRCT). Nineteen patients had ILD+SSc, and 14 had no lung involvement (no ILD-SSc); data were compared with those from 45 healthy controls. PINP and PIIINP were assessed in all 3 groups. RESULTS Patients with SSc had higher PINP and PIIINP vs controls (P=.001, P<.001, respectively). Compared to no ILD-SSc patients, those with ILD+SSc had longer disease duration in years (P=.005), higher modified Rodnan skin score (P<.001), higher Health Assessment Questionnaire-Disability-Index scores (P<.001), higher topoi U/mL (P<.001), PINP (49.28±28.63 vs. 32.12±18.58μg/L, P=.05), and PIIINP (4.33±1.03 vs. 2.67±1.26μg/L, P<.001) levels. ILD severity based on total HRCT correlated with PINP (r=.388, P=.03) and PIIINP (P=.594, P<.001). On adjusted analysis, ILD severity was associated with disease duration (P=.037), PIIINP (P=.038), and topoi (P=.045). CONCLUSIONS PINP and PIIINP are useful markers for severe ILD+SSc, suggesting they could play a role in the follow-up of this complication in SSc.