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.