Telomere Length of Peripheral Blood Leukocytes Predicts Disease Severity and Worse Survival in Systemic Sclerosis.

OBJECTIVE Peripheral blood leukocyte telomere length (PBL-TL) shortening is associated with systemic sclerosis related interstitial lung disease (SSc-ILD). However, its association with other organ involvement, disease severity, and survival remains unclear. This study aimed to define the relationship of TL with SSc-specific disease manifestations and outcomes. METHOD PBL-TL was measured by quantitative PCR in 244 patients with SSc and 314 healthy controls. Multivariate modeling was utilized to assess the association of PBL-TL with disease severity and event-free survival. Longitudinal changes in PBL-TL were measured in a subset of patients. Telomere length was quantified in SSc skin and lung tissues by telomere fluorescence in situ hybridization. RESULTS PBL-TL was significantly shorter in patients with SSc than healthy controls. Shortened PBL-TL was associated with presence and severity of ILD and pulmonary hypertension (PH) with the shortest PBL-TL found in subjects with concurrent ILD and PH (p=0.04). PBL-TL was not associated with skin disease or peripheral vascular disease. Shorter PBL-TL was associated with hospitalizations (p<0.01) and worse event-free survival (p=0.03). Patients with early SSc had a faster rate of PBL-TL shortening compared to patients with longer disease duration (p = 0.04). TL was shorter in SSc-ILD lung epithelial cells (p=0.01) while no difference was found in epithelial cells of SSc skin (p=0.82). CONCLUSION Short PBL-TL is associated with pulmonary disease severity and predicts worse SSc clinical outcomes. This study provides rationale to further investigate the role of telomere dysfunction in SSc pathogenesis and validate TL as a prognostic biomarker in SSc.