Eva Petrow, Changyong Feng, Ashley Frazer-Abel, Roberta Goncalves Marangoni, Katie Lutz, William C. Nichols, V. Michael Holers, Christopher Ritchlin, R. James White III, Benjamin D. Korman
University of Rochester Medical Center. University of Colorado School of Medicine. Cincinnati Children’s Medical Center and University of Cincinnati College of Medicine.
United States
Seminars in Arthritis and Rheumatism
Semin Arthritis Rheum 2024;
DOI: 10.1016/j.semarthrit.2024.152554
Abstract
Background: Activation of the complement cascade is thought to play a role in scleroderma vasculopathy. We previously showed that complement factor D was elevated in patients with limited cutaneous SSc and pulmonary arterial hypertension (PAH). In this study, we sought to assess multiple relevant components of the complement cascade to determine if they are altered in SSc-PAH, as well as their potential utility as biomarkers of disease severity and progression.
Methods: Complement components (n = 14) were measured using multiplex assays in 156 patients with SSc-PAH from a multi-site repository and were compared to 33 patients with SSc without PAH, and 40 healthy controls. Data were evaluated for correlations between complement levels, right heart catheterization measures, and clinical endpoints including 6-minute walk distance. To assess complement longitudinally, serum complement levels were assayed at 0, 4, 12, 24, 36 and 48 weeks in 52 SSc-PAH patients who participated in a prior clinical trial.
Results: We found that factor D was significantly elevated in SSc-PAH compared to SSc without PAH (p < 0.0001) and was highly sensitive and specific for SSc-PAH (AUC=0.82, p < 0.001). In SSc-PAH patients, alterations in factor H, C4, and factor D were associated with measures of PAH disease severity including right heart catheterization measurements (cardiac output, right atrial pressure, and VO2 max), survival, and 6-minute walk distance. No significant changes in complement levels or clinical associations were seen over time or associated with treatment in the longitudinal clinical trial study.
Conclusion: Our work confirms prior studies demonstrating a role for complement activation in SSc vascular disease and elevations of factor D in a large SSc-PAH population. Further, factor H and other complement factors are associated with severity of PAH including mortality. Taken together, these findings suggest that the alternative complement pathway plays a role in SSc-PAH pathogenesis and may serve as a biomarker to inform diagnosis and prognosis.
Category
Class I. Pulmonary Hypertension Associated with Connective Tissue Disease
Potential Biomarkers Associated with Pulmonary Vascular Disease
Age Focus: Pediatric Pulmonary Vascular Disease or Adult Pulmonary Vascular Disease
Fresh or Filed Publication: Fresh (PHresh). Less than 1-2 years since publication
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