Elevated serum levels of immunoglobulin G (IgG) antibodies to malondialdehyde (MDA) protein modifications are linked to high disease activity, active lupus nephritis, and biomarkers of systemic inflammation in patients with systemic lupus erythematosus (SLE), according to the results of a cross-sectional study published in Arthritis Research & Therapy.
Researchers examined serum IgG anti-MDA levels using enzyme-linked immunosorbent assay in 398 patients with SLE from the Swedish Karolinska cohort and compared them with findings from 225 patients with SLE from New York University and Johns Hopkins University.
In these 2 independent cohorts, IgG anti-MDA levels were significantly associated with disease activity, as assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI; P <.0001). Meta-analysis also showed that high anti-MDA IgG levels were significantly linked to active disease, (SLEDAI ≥6; odds ratio, 2.7; 95% CI, 1.9-3.9; P <.0001).
Moreover, IgG anti-MDA was directly correlated with erythrocyte sedimentation rate,
C-reactive protein, soluble tumor necrosis factor receptors, and vascular cell adhesion molecule 1 measurements. In addition, IgG anti-MDA was inversely correlated with complement factors. Investigators found that IgG anti-MDA levels were significantly increased in patients with SLE who had active nephritis (P =.0005), and was associated with cystatin C estimated glomerular filtration rate and albuminuria.
The researchers concluded that the natural antibody reactivity demonstrated in this study may have a potential prognostic utility and may contribute to current findings of the autoimmune pathogenesis of SLE. IgG immune responses to oxidation-associated protein modifications in patients with SLE warrants additional investigation.
Hardt U, Larsson A, Gunnarsson I, et al. Autoimmune reactivity to malondialdehyde adducts in systemic lupus erythematosus is associated with disease activity and nephritis. Arthritis Res Ther. 2018;20(1):36.