The autoimmune response to chromatin (Chr) or one of the nucleosome components (double stranded (ds)DNA and histones) is typically associated with the development of systemic lupus erythematosus (SLE). Related autoantibodies (Ab) are heterogeneous and, among them, anti-dsDNA Ab are part of the classification criteria and recommended for monitoring SLE with regards to lupus flares and therapy responses. However, anti-dsDNA Ab biomarker performances are weak; therefore, coupling anti-dsDNA with anti-Chr Ab can be proposed, which is the aim of this study. In this single center study from 2009 to 2024, 269 SLE patients with follow-up information were retrospectively selected from a population of 646 individuals, including 325 SLE patients, who tested positive for anti-dsDNA and/or anti-Chr Ab (Bioplex 2200™). Bio-clinical information during follow-up were assessed at several time points through medical records in order to explore associations between the anti-dsDNA/Chr Ab profile with disease presentation, and anti-dsDNA/Chr Ab fluctuations with disease activity using clinical SLEDAI-2K, flares requiring specific treatment, and the therapeutic response. At inclusion in the follow-up analysis, corresponding to diagnosis (116/269, 43.1 %) or flare (153/269, 56.9 %), SLE patients were subdivided into three serological groups: the double positive dsDNA/Chr group (DP+, 190/269: 70.6 %), followed by the single positive Chr group (SP-C+, 42/269: 15.6 %), and the single positive dsDNA group (SP-D+, 37/269: 13.8 %). The DP + group, which presented important anti-dsDNA/Ab variations during follow-up, was at risk to develop lupus nephritis (56.8 % versus 2.4 % in SP-C+ and 29.7 % in SP-D+ groups, p < 0.04) and serositis (30 % versus 9.5 % in SP-C+ group, p = 0.006). During follow-up, anti-dsDNA and Chr Ab levels in the SP-C+ and SP-D+ groups remained stable over time irrespective of disease activity, flares, and therapeutic response. Regarding the DP + group, disease activity was correlated with both anti-dsDNA (RmCorr = 0.46, p = 1.6x110-⁹¹) and anti-Chr (RmCorr = 0.38, p = 2.8x10-⁶⁰) Ab levels, which can be used to predict flares. Following therapy introduction, Ab reduction occurred in all patients from the DP + group with a more pronounced effect reported in complete responders. coupling anti-dsDNA with anti-Chr Ab detection at disease initiation/flare allows definition of endotypes, which is useful to follow disease activity, predict lupus nephritis/serositis, and anticipate therapeutic response in the DP + group.

Lupus nephritis (LN) diagnosis and follow-up requires noninvasive biomarkers. Therefore, the added value of coupling the urinary soluble (s)CD163/creatinuria ratio with serological markers was evaluated in a real-world clinical practice. To this end, a monocentric and retrospective study was conducted in 139 SLE patients with biopsy-proven nephritis having an active LN (LN-A, n = 63 with a positive SLEDAI-renal score) or inactive (n = 76), as well as 98 non-renal SLE patients. The urinary sCD163/creatinuria ratio outperformed serological markers for predicting LN-A (AUC>0.972; p < 10^-4 with a 100 % specificity threshold fixed at 320 ng/mmol), and for monitoring renal activity allowing prediction of impending flares and remissions in follow-up (AUC = 0.789, p < 10^-4). LN-A patients with an elevated spot proteinuria/creatinuria ratio (p = 8 × 10^-6) and sCD163/creatinuria ratio (p = 10^-3) were at risk for developing end-stage kidney disease but sCD163/creatinuria ratio cannot substitute kidney biopsy to discriminate LN-A from other glomerulonephritis. Among serological markers (n = 14), anti-dsDNA and anti-C1q antibodies (Abs) (AUC>0.750 versus non-LN patients, and AUC>0.640 versus LN-IR patients) best predicted LN-A, and higher levels were retrieved in class III/IV proliferative LN-A. In multivariate logistic regression analysis, the urinary sCD163/creatinuria ratio remained the only statistically significant biomarker to predict LN-A (p < 0.001). In conclusion, and as compared to classical serological markers, the urinary sCD163/creatinuria ratio provides an additional parameter for monitoring LN patients.

T cells are known to be involved in the pathogenesis of rheumatoid arthritis (RA). Accordingly, and to better understand T cells’ contribution to RA, a comprehensive review based on an analysis of the Immune Epitope Database (IEDB) was conducted. An immune CD8+ T cell senescence response is reported in RA and inflammatory diseases, which is driven by active viral antigens from latent viruses and cryptic self-apoptotic peptides. RA-associated pro-inflammatory CD4+ T cells are selected by MHC class II and immunodominant peptides, which are derived from molecular chaperones, host extra-cellular and cellular peptides that could be post-translationally modified (PTM), and bacterial cross-reactive peptides. A large panel of techniques have been used to characterize (auto)reactive T cells and RA-associated peptides with regards to their interaction with the MHC and TCR, capacity to enter the docking site of the shared epitope (DRB1-SE), capacity to induce T cell proliferation, capacity to select T cell subsets (Th1/Th17, Treg), and clinical contribution. Among docking DRB1-SE peptides, those with PTM expand autoreactive and high-affinity CD4+ memory T cells in RA patients with an active disease. Considering original therapeutic options in RA, mutated, or altered peptide ligands (APL) have been developed and are tested in clinical trials.

Oral microbiome changes take place at the initiation of rheumatoid arthritis (RA); however, questions remain regarding the oral microbiome at pre-RA stages in individuals with clinically suspect arthralgia (CSA). Two cross-sectional cohorts were selected including 84 Tatarstan women (15 early-RA as compared to individuals with CSA ranging from CSA = 0 [n = 22], CSA = 1 [n = 19], CSA = 2 [n = 11], and CSA ≥ 3 [n = 17]) and 42 women with established RA (median: 5 years from diagnosis [IQ: 2–11]). Amplicon sequence variants (ASVs) obtained from oral samples (16S rRNA) were analyzed for alpha and beta diversity along with the abundance at the genus level. A decrease in oral Porphyromonas sp. is observed in ACPA-positive individuals, and this predominates in early-RA patients as compared to non-RA individuals irrespective of their CSA score. In the RA-established cohort, Porphyromonas sp. and Aggregatibacter sp. reductions were associated with elevated ACPA levels. In contrast, no associations were reported when considering individual, genetic and clinical RA-associated factors. Oral microbiome changes related to the genera implicated in post-translational citrullination (Porphyromonas sp. and Aggregatibacter sp.) characterized RA patients with elevated ACPA levels, which supports that the role of ACPA in controlling the oral microbiome needs further evaluation.

Bacterial recombinant cysteine protease Ides (imlifidase, Idefirix®, Hansa Biopharma) is used to prevent humoral transplant rejection in highly HLA-sensitized recipients, and to control IgG-mediated autoimmune diseases. We report the case of a 51 years old woman suffering from lupus nephritis with end stage kidney disease, grafted for the second time and pre-treated with imlifidase. The patient was HLA-hypersensitized (calculated Panel Reactive Antibodies [Abs], cPRA>99 %) and has three preformed Donor Specific Antibodies (DSA). Circulating immunoglobulins were monitored at initiation (0, 6, 36, 72 and 96 h), and at Ab recovery one and two months following imlifidase injection. From baseline, the higher depletion was reported after 36h for total IgG (−75 %) and IgG subclasses (−87 % for IgG1, IgG2 and IgG3, -78 % for IgG4), while no significant impact on IgA and IgM was observed. Anti-SSA 60 kDa and anti-SSB auto-Abs quickly decreased after imlifidase injection (−96 % for both after 36 h) as well as post-vaccinal specific IgG (−95 % for tetanus toxoid, −97 % for pneumococcus and −91 % for Haemophilus influenzae Abs after 36 h). At the Ab recovery phase, total IgG and anti-SSA60/SSB Abs reached their initial level at two months. Regarding alloreactive Abs, anti-HLA Abs including the three DSA showed a dramatic decrease after injection with 100 % depletion from baseline after 36 h as assessed by multiplex single bead antigen assay, leading to negative crossmatches using both lymphocytotoxicity (LCT) and flow cell techniques. DSA rebound at recovery was absent and remained under the positivity threshold (MFI = 1000) after 6 months. The findings from this case report are that imlifidase exerts an early depleting effect on all circulating IgG, while IgG recovery may depend in part from imlifidase's capacity to target memory B cells.

Lupus erythematosus is a complex autoimmune disease characterized by skin and/or systemic involvement. Among systemic disorders, half of the patients will experience non-specific digestive symptoms, usually due to drug medication or transitory infections. In rare cases, lupus enteritis can be observed, and its diagnosis may precede the disease and/or be associated with an inflammatory bowel disease (IBD). Among the underlying mechanisms explaining the digestive damages observed in systemic lupus erythematosus (SLE) and the intestinal barrier function (IBF), increased intestinal permeability, microbiota dysbiosis, and intestinal immune system dysregulations are described in numerous murine and human studies. New therapeutic approaches in addition to conventional treatments are evoked in order to better control the IBF disruption and maybe prevent the onset or worsening of the disease. Thus, the aims of this review are to present the alterations of the digestive tract in SLE patients and the link between SLE and IBD as well as how the different elements of the IBF could participate in SLE pathogenesis.