Relation of Antibodies Against Oxidized Low Density Lipoproteins to Disease Activity and Cardiovascular Affection in Systemic Lupus.

The aim of this study is to correlate the autoantibody against oxidized LDL with disease activity and cardiovascular affection in patients with SLE.

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease affecting mainly women of fertile age. It is characterized by hyperactivity of B-cells and by overproduction of autoantibodies without organ specificity, many of which contribute to the formation of immunocomplexes. Their deposition in tissues and blood vessels results in inflammatory organ impairment (Khairy et al., 2017). As for the laboratory findings in SLE, production of autoantibodies without organ specificity aimed at nuclear, cytoplasmic, and surface antigens of the patient's body is typical. The most common SLE manifestations include involvement of skin, joints, cardiovascular system, lungs, renal glomeruli, central nervous system or hematopoiesis.

SLE can result in failure of the involved organs, severe forms of SLE thus bein gassociated with significant mortality (Pashnina et al., 2021).

Cardiovascular involvement is associated with increased morbidity and mortality of SLE patients. The most common SLE-related cardiovascular events are myocardial infarctions (MIs), cerebrovascular events, thromboembolic events (TEs), heart failure, and sudden death.

Cardiovascular events are proportionally higher in SLE compared to general populations of comparable age and sex (Ramirez et al., 2020). The pathogenic mechanisms of different cardiac diseases in SLE are still incompletely understood. Traditional risk factors for Cardiovascular affection, such as older age, high blood pressure (BP), high cholesterol and triglycerides, smoking, obesity, diabetes mellitus, and - last but not least - SLE therapy all play a critical role. These factors alone cannot adequately explain the increased incidence of cardiovascular disease commonly reported in patients with SLE. Metabolic syndrome was considered a remarkable risk factor for the development of subclinical atherosclerosis and increased carotid intima-media thickness The non-traditional biomarkers included both leptin and homocysteine, where leptin acts on the immune system as aproinflammatory cytokine. It promotes the proliferation and activation of T lymphocytes and induces production of Th1 cytokines. Homocysteinelevels have been identified as a predictor of atherosclerosis in patients with SLE, in whom high levels may be predictive levels of coronary calcification, platelet progression and increased IMT (Khairy et al., 2017).

Specific antibodies cause oxidation of low density lipoprotein (LDL) particles, thus accentuating their atherogenic effect, or exert a negative influence on the character of physiologically protective High density lipoprotein (HDL) particles. Endothelial dysfunction within the vascular system ensues, increasing its vulnerability, affinity to lipoproteins and activity of enzymes accelerating the development of atherosclerosis (Li et al., 2020).

LDLs are transported into artery walls, where they become trapped and bound in the extracellular matrix of the subendothelial space. These trapped LDLs are then seeded with reactive oxygen species produced by nearby artery wall cells, resulting in the formation of proinflammatory Oxidized LDL (OxLDL). oxLDL plays an important role in atherogenesisand may contribute to the immune activation and inflammation present in the atherosclerotic lesions, because it has chemotactic, immune-stimulatory, and toxic properties and is taken up by macrophages and other cells in the atherosclerotic plaque, which develop into foam cells. Epitopes characteristic of oxidized LDL can be found in atherosclerotic lesions by immunocytochemical techniques and atherosclerotic lesions contain immunoglobulins that recognize oxLDL (Ammar et al., 2021).

Eligibility Criteria:
Inclusion Criteria:

- 1. Patients aged ≥ 18 years. 2. Patients fulfilling the American College of Rheumatology (ACE) criteria for SLE (Aringer et al., 2019).

3. Patients diagnosed with SLE and without cardiovascular disease (CVD) impairment before the diagnosis of SLE was established.

Exclusion Criteria:

1. Patients aged less than18 years.
2. Patients not fulfilling the American College of Rheumatology (ACE) criteria for SLE (Aringer et al., 2019).