Reactivity in ELISA with DNA-loaded nucleosomes in patients with proliferative lupus nephritis

Abstract

Autoantibodies against nucleosomes are considered a hallmark of systemic lupus erythematosus (SLE). We compared in patients with proliferative lupus nephritis the diagnostic usefulness of a dsDNA-loaded nucleosome ELISA (anti-dsDNA-NcX) with ELISAs in which dsDNA or nucleosomes alone were coated. First, we analysed whether DNA loading on nucleosomes led to masking of epitopes by using defined monoclonal anti-DNA, anti-histone and nucleosome-specific autoantibodies to evaluate the accessibility of nucleosomal epitopes in the anti-dsDNA-NcX ELISA. Second, autoantibody levels were measured in these 3 ELISAs in 100 patients with proliferative lupus nephritis (LN) before immunosuppressive treatment and in 128 non-SLE disease controls. In patients with LN inter-assay comparisons and associations with clinical and serological parameters were analysed. The panel of monoclonal antibodies revealed that all epitopes were equally accessible in the anti-dsDNA-NcX ELISA as in the two other ELISAs. Patients with proliferative lupus nephritis were positive with dsDNA-loaded nucleosomes in 86%, with DNA in 66% and with nucleosomes in 85%. In the non-lupus disease control group these frequencies were 1.6% (2 out of 128) for both the anti-dsDNA-NcX and the anti-dsDNA ELISA and 0% in the anti-nucleosome ELISA. The levels in the anti-dsDNA-NcX ELISA were high in a group of patients with LN that showed absent reactivity in the anti-DNA or low levels in the anti-nucleosome ELISA. Anti-dsDNA-NcX positivity was associated with higher SLEDAI scores within this group. Within nucleosome-based ELISAs, we propose the anti-dsDNA-NcX ELISA as the preferred test system.

A reverse translational study on the effect of rituximab, rituximab plus belimumab, or bortezomib on the humoral autoimmune response in SLE

“…Immunomonitoring of the humoral autoimmune response in SLE is challenging because a wide variety of autoantibodies mediate organ damage directly or indirectly through the formation of ICs [ 2 ], which subsequently trigger the complement system and NET formation [ 6 , 9 ]. Anti-dsDNA [ 39 ], -histones [ 40 ], -nucleosomes [ 41 ] and -C1q [ 42 ] autoantibodies were shown to be involved in IC formation, correlated with disease activity, and thereby are closely linked to the pathogenesis of SLE. Specifically, anti-C1q antibodies have a pathogenic role in LN, because they activated the classical and lectin pathway of the complement system [ 43 ], and C1q-containing ICs are found in the glomeruli [ 44 ].…”

Elimination of Nucleoproteins in Systemic Lupus Erythematosus and Antinuclear Autoantibodies Production

“…In most SLE cases, serum anti-dsDNA and anti-nucleosome antibodies are presented at the same time [39]. Furthermore, chromatin immunization induces not only anti-nucleosome but also anti-dsDNA and anti-nucleosome antibodies, possibly through epitope spreading [40].…”

A leukocyte activation test identifies food items which induce release of DNA by innate immune peripheral blood leucocytes

“…We have identified that release of DNA and activation of TLR9 is an important injury pathway in acetaminophen induced liver injury, pancreatitis and nonalcoholic steatohepatitis [ 21 – 23 ]. Others have shown this pathway to be important in systemic lupus erythematosus (SLE), and liver ischemia reperfusion injury [ 24 , 25 ].…”