Abstract
Objectives
To identify and quantify the level of CD34+ CD133+ CD309+ circulating angiogenic cells (CAC) and explore factors associated with the level of CAC in patients with systemic lupus erythematosus (SLE).
Methods
The peripheral blood mononuclear cells of consecutive SLE patients and demographically matched healthy controls (HC) were extracted and identified, enumerated and compared for CAC levels by multi-colour flow cytometry based on the European League Against Rheumatism Scleroderma Trials and Research (EUSTAR) recommendation. Meta-analyses by combining the current and previous case-control studies were performed, aiming to increase the statistical power to discern the difference in CAC level between SLE patients and HC. Mixed-model meta-regression was conducted to explore potential demographic and clinical factors which were associated with CAC level.
Results
A lower level of CAC was found in 29 SLE patients compared with 24 HC (10.76 ± 13.9 vs 24.58 ± 25.4 cells/ml, p= 0.015). Random-effects meta-analyses of the current and 6 previously published case-control studies involving 401 SLE patients and 228 HC revealed a lower CAC level compared with HC (SMD= -2.439, p= 0.001). Meta-regression analysis demonstrated that hydroxychloroquine use was associated with a more discrepant CAC level between both groups (p= 0.01115).
Conclusion
SLE patients had a significantly lower CD34+ CD133+ CD309+ CAC level than HC and hydroxychloroquine use was associated with a more discrepant CAC level between SLE patients and HC. This study triggers further observational, interventional and mechanistic studies to address the beneficial impact of hydroxychloroquine on the functionality of CAC in SLE patients.
Semiparametric regression analysis of mean residual life with censored survival data