The alternative complement pathway activity may depend on plasma malondialdehyde level in systemic lupus erythematosus patients: Preliminary results

BackgroundMalondialdehyde (MDA) is a marker of oxidative stress (OS) and one of the major alternative complement pathway (ACP) activators associated with systemic lupus erythematosus (SLE) activity. ACP is the principal mediator of SLE inflammation and progression.Aim of the workTo investigate the association between the ACP functional activity and plasma MDA in SLE patients.Patients and methodsSixteen consecutive SLE patients were analyzed for their complement profile and oxidative stress measurement. 60 healthy subjects were included as a control group. The Complement components C3, C4 and properdin-factor B (PfB) were assessed, ACP activity was assayed according to alternative hemolytic 50 (AH50). Plasma total lipid peroxide quantification was performed by assessing the plasma MDA. Total antioxidant capacity was measured with oxygen radical absorbance capacity (ORAC). OS ratio was calculated by dividing the total antioxidant capacity by MDA.ResultsSixteen patients (13 females and 3 males) with a mean age of 27.86 ± 6.26 years and a disease duration 69.65 ± 54.65 months were included. There was a significant increase of MDA in the patients (MFI = 613 ± 56.21) compared to the control (MFI = 460 ± 37.85) (p = 0.003). C3 was significantly consumed and MDA increased in the low AH50 compared to the normal AH50 patients (p = 0.02 and p = 0.01 respectively). AH50 significantly negatively correlated with the C3 (p = 0.02) and MDA (p = 0.048). There was lack of any association between ORAC and ACP. Properdin factor B significantly negatively correlated with C3 (p = 0.007).ConclusionsThese initial results encourage future in-depth studies on the association of OS–ACP in SLE pathogenesis.