ABSTRACT
Introduction: Complement activation emerged as a key actor of anti-neutrophil cytoplasmic antibodies-associated vasculitis (AAV). Whether serum levels of C3 (sC3) or C3 kidney deposition may help to refine the prognosis of AAV remains elusive. Methods: Retrospective multicentric study that included 154 patients with a first flare of AAV and sC3 (n = 143) or C3 kidney staining (n = 95) available at diagnosis. Clinical presentations, kidney pathology, and survival of patients with normal or low sC3 were compared using univariate analyses, Kaplan-Maier curves with log-rank comparison, or multivariate Cox' model, as appropriate. Results: 20 patients (14 %) had low sC3. sC3 (as bivariate low/normal or as a continuous variable) was associated with 5-year mortality but not with kidney survival. C3 kidney deposition (C3+) was identified in 23 patients who were characterized by more frequent chronic hypertension and lower eGFR at presentation (p = 0.04). C3+ correlated with IgG, IgM, C1q deposition (p = 0.07, p < 0.0001 and p = 0.003, respectively). Chronicity and activity scores were similar in C3+ and C3- patients. Among C3+ patients, those with C3 deposition ≥2+ had lower eGFR at presentation (p = 0.006) and were more frequently classified as sclerotic using the Berden classification (p = 0.04) and as 'high risk' using the Brix score (p = 0.03). However, eGFR improvement following induction regimen was similar between C3+ and C3- patients, and kidney survival at 5 years was similar. Conclusions: Correlation of sC3 with mortality confirms mechanistic links between complement pathways and AAV, but the lack of clear predictive sC3 cut-off and the similar kidney outcome irrespective of C3 deposition precludes their use as biomarkers of AAV outcomes and response to treatment.
ABSTRACT
Inflammatory bowel diseases (IBDs), which include Crohn's disease and ulcerative colitis, are multifactorial diseases that involve in particular a modification of the gut microbiota, known as dysbiosis. The initial sets of metataxonomic and metagenomic data first made it possible to approximate the microbiota profile in IBD. In addition, today the new 'omics' techniques have enabled us to draw up a functional and integrative map of the microbiota. The key concern in IBD is to develop biomarkers that allow us to assess the activity of the disease and predict the complications and progression, while also guiding the therapeutic care so as to develop personalized medicine. In this review, we present all of the latest discoveries on the microbiota provided by "omics" and we outline the benefits of these techniques in developing new diagnostic, prognostic and therapeutic tools.
