Do circulating antibodies against C1q reflect the activity of lupus nephritis?

Abstract

IntroductIonThe results of recent studies suggest that there is a link between the presence of antibodies against C1q (anti-C1q Abs) and kidney involvement in systemic lupus erythematosus (SLE). However, it remains unclear whether the clinical symptoms of lupus nephritis (LN) may be associated with the presence of anti-C1q Abs in serum.objEctIvEs The aim of the study was to compare the prevalence and levels of anti-C1q Abs and antibodies against double-stranded DNA (anti-dsDNA Abs), circulating immune complexes binding C1q (CIC-C1q), as well as complement components C3 and C4 in the sera of patients with LN in relation to the clinical activity of SLE and symptoms of LN. PAtIEnts And mEthodsThe study involved 48 patients with LN and 66 healthy controls. Anti-dsDNA Abs, anti-C1q Abs, and CIC-C1q levels were determined by immunoenzymatic methods, while C3 and C4 by immunoturbidimetry. SLE activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI).rEsuLts Anti-dsDNA Abs, anti-C1q Abs, and CIC-C1q were detected in 77%, 60%, and 43.7% of the patients with LN, respectively. The prevalence and mean levels of anti-dsDNA and anti-C1q Abs were significantly higher in patients with active LN than in those with inactive LN or controls. The levels of C3 and C4 were significantly lower in active LN than in inactive LN or controls. In active LN, a positive correlation between anti-C1q and anti-dsDNA Abs was observed. In patients with detected anti-C1q Abs, microhematuria (59% vs. 16%, P = 0.003), urinary casts (28% vs. 8%, P = 0.02), and low levels of serum C3 (P = 0.03) and C4 (P = 0.01) were observed statistically significantly more often.concLusIons Simultaneous presence of hematuria and anti-C1q Abs may indicate an ongoing inflammatory process in the glomeruli in patients with SLE.

β2-microglobulin as a marker of systemic lupus erythematosus activity

“…[2][3][4] In Polish conditions, circulating anti-C1q antibodies have been recently studied as the marker for lupus nephritis, while anti-ribosomal P protein antibodies titer and IL-10 concentration in exhaled breath condensate as general markers of the disease activity. [5][6][7] The search for new SLE activity markers is ongoing. In recent years, the effectiveness of marking the β2-microglobulin (β2M) serum concentrations in monitoring SLE activity has been consistently highlighted.…”

Diagnostic value of serum anti-C1q antibodies in patients with lupus nephritis: a meta-analysis

“…After full text identification, 93 citations were excluded for the following reasons: mechanism studies, quantitative data without cut-off value, statistical analysis without relative risk or odds ratio (OR), SLE patients without renal involvement were not included as a control group or two by two fourfold table cannot be constructed. Ultimately, only 25 studies8,[10][11][12]16,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] met the eligibility criteria of the meta-analysis, among them 22 studies8,10,12,16,[25][26][27][28][29][31][32][33][34][35][36][37][38][40][41][42][43] had sufficient data for the analysis in LN diagnosis and 9 studies10,…”

Autoantibodies against complement components in systemic lupus erythematosus – role in the pathogenesis and clinical manifestations

“…In patients with detected anti-C1q antibodies, the presence of microhaematuria (59% vs 16%, P = 0.003), urinary casts (28% vs 8%, P = 0.02), and low levels of serum C3 ( P = 0.03) and C4 ( P = 0.01) is significantly higher. 4 Stojan and Petri 5 have shown that anti-C1q in combination with anti-dsDNA and low complement have the strongest serological association with renal involvement. Furthermore, data show that anti-C1q antibodies correlate with a histopathological type of nephritis.…”