Area of Science:

• Immunology
• Hematology
• Rheumatology

Background:

• Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease.
• SLE is associated with an increased risk of thrombotic events.
• Biomarkers for early disease activity and thrombotic risk in SLE are needed.

Purpose of the Study:

• To investigate the correlation between Reticulocytes-C4d (R-C4d) and Platelets-C4d (P-C4d) levels and disease activity in SLE.
• To assess the relationship between R-C4d and P-C4d with markers of coagulation activation and endothelial injury.
• To evaluate the potential of R-C4d and P-C4d as indicators of early SLE activity and prothrombotic risk.

Main Methods:

• Study included 90 women: 30 healthy controls, 30 with low SLE activity (SLEDAI ≤4), and 30 with active SLE (SLEDAI >4).
• Reticulocytes-C4d (R-C4d) and Platelets-C4d (P-C4d) were measured using flow cytometry (Median Fluorescence Intensity - MFI).
• Endothelial injury and hypercoagulability markers (Thrombomodulin, D-dimer) were quantified.

Main Results:

• Higher R-C4d MFI correlated with recent SLE disease activity.
• Higher P-C4d expression was linked to an elevated risk of thrombotic complications.
• Active SLE patients exhibited increased levels of soluble thrombomodulin and D-dimer.

Conclusions:

• R-C4d is a valuable marker for monitoring early SLE disease activity.
• P-C4d may serve as an important tool for identifying a prothrombotic phenotype in SLE patients.
• Elevated D-dimer and thrombomodulin levels in conjunction with P-C4d confirm a hypercoagulable state and increased thrombotic risk in active SLE.