Background: Systemic lupus erythematosus (SLE) is a chronic multisystem
autoimmune disease characterized by complex clinical manifestations and chronic
inflammatory processes with failure of immunoregulatory mechanisms. Kidney is one
of the most commonly affected organs. Considering the morbidity associated with
SLE and particularly with lupus nephritis (LN), it is important to identify novel
biomarkers of disease activity which could aid in the detection and assessment of
flares and degree of activity. At present, activity of SLE is assessed based on clinical
symptoms and biochemical parameters such as autoantibody (e.g antinuclear
antibody (ANA)) and serum complement. However, these biomarkers are not specific
for evaluating renal activity. Renal biopsy is the gold standard for assessment of
kidney damage and disease activity, but its usage is restricted as it is an invasive
procedure. Aim of the work: In the present study, plasma level of advanced oxidation
protein products (AOPPs) and peripheral blood mononuclear cells nuclear factor-κB
(PBMCs NF-κB) level as well as serum levels of fetuin-A, 25-hydroxyvitamin D
(25OHD), calcium (Ca), inorganic phosphate were studied as novel biomarkers of LN
activity and progression. Methods: The study included 30 SLE female patients, 15
without nephritis (group II) and 15 with nephritis (group III), in addition to 15 agematched
healthy controls (group I). Overnight fasting blood was collected from all
subjects for measurement of plasma AOPPs level, PBMCs NF-κB level and serum
fetuin-A level, 25OHD level, Ca and inorganic phosphate levels as well as calculation
of calcification risk index (CRI). Results: Plasma AOPPs, PBMCs NF-κB, serum
inorganic phosphate levels and CRI were significantly higher in SLE patients (group
II) than age-matched healthy controls (group I) (p<0.05) with the highest level in
patients with LN (group III) meanwhile, serum fetuin-A and 25OHD levels were
significantly lower in SLE patients than age-matched healthy controls (p<0.05) with
the lowest level in LN patient group. In addition plasma AOPPs, PBMCs NF-κB
levels and CRI showed significantly positive correlation meanwhile, fetuin-A and
25OHD levels showed significantly negative correlation with serum creatinine, 24
hours urinary albumin, erythrocyte sedimentation rate (ESR), C reactive protein
(CRP), ANA, anti double stranded DNA (Anti- dsDNA) antibodies levels and SLE
disease activity index (SLEDAI). Conclusions: In SLE patients, high PBMCs NF-κB
and plasma AOPPs levels as well as CRI while low levels of fetuin-A and 25OHD
were related to disease activity and progression.