An update on autoinflammatory diseases

First author: S. Georgin-Lavialle

Abstract:

Autoinflammatory diseases (AIDs) are defined as disorders of innate immunity. They were initially defined in opposition to autoimmune diseases, due to the absence of involvement of the adaptive immune system and circulating autoantibodies. The 4 IADs first described are known as the “historic” IADs and include: familial Mediterranean fever (associated with mutations in the MEFV gene), cryopyrinopathies (associated with mutations in NLRP3), tumor necrosis factor receptor-associated periodic syndrome (associated with mutations in TNFRSF1A) and mevalonate kinase deficiency (associated with mutations in MVK). Over the past 10 years, more than 50 new monogenic IBDs have been discovered thanks to advances in genetics. Diagnosis is facilitated by personal and family history-taking and detailed analysis of the signs and symptoms associated with febrile attacks, which must be associated with the presence of elevated blood biomarkers of inflammation. Increasingly powerful genetic analysis techniques can help refine the diagnosis. This chapter describes the main types of IJD, and helps to guide the clinician in the suspicion and diagnosis of IJD.

MAi en français.pdf

Download PDF • 1.35MB

Functional diversity of NLRP3 gain-of-function mutants associated with CAPS autoinflammation

First author: Camille Cosson and al.

Link to article: DOI: 10.1084/jem.20231200

Abstract

NLRP3-associated autoinflammatory disease is a heterogenous group of monogenic conditions caused by NLRP3 gain-of-function mutations associated with CAPS autoinflammation. The poor functional characterization of most NLRP3 variants hinders diagnosis despite efficient anti-IL-1 treatments.

Additionally, while NLRP3 is controlled by priming and activation signals, gain-of-functions have only been investigated in response to priming. Here, we characterize 34 NLRP3 variants in vitro, evaluating their activity upon induction, priming, and/or activation signals, and their sensitivity to four inhibitors.

We highlight the functional diversity of the gain-of-function mutants and describe four groups based on the signals governing their activation, correlating partly with the symptom severity. We identify a new group of NLRP3 mutants responding to the activation signal without priming, associated with frequent misdiagnoses.

Our results identify key NLRP3 residues controlling inflammasome activity and sensitivity to inhibitors, and antagonistic mechanisms with broader efficacy for therapeutic strategies. They provide new insights into NLRP3 activation, an explanatory mechanism for NLRP3-AID heterogeneity, and original tools for NLRP3-AID diagnosis and drug development.

Functional diversity of NLRP3.pdf

Download PDF • 10.21MB

A20 Haploinsufficiency (HA20) is a monogenic autoinflammatory disease associated with an autosomal dominant mutation in the TNFAIP3 gene.: what does the clinician need to know?

I. Elhani a,b,∗, A. Aoubac, Q. Riller d, H. Vergneault e, G. Boursier f,g, F. Rieux-Laucat d, V. Hentgena, S. Georgin-Lavialle b,e,∗

A20 Haploinsufficiency (HA20) is a monogenic autoinflammatory disease associated with an autosomal dominant mutation in the TNFAIP3 gene. It induces a defect in the inactivation of the pro-inflammatory NF-B pathway. Less than 200 cases have been described worldwide. The clinical picture of the disease is essentially based on the association of recurrent fever and/or biologic inflammatory syndrome, aphtosis, often bipolar, and cutaneous folliculitis. However, the clinical spectrum of HA20 is very broad, including gastrointestinal (mainly colonic ulceration), articular, cutaneous, pericardial and lymph node involvement, as well as frequent association with organ-specific or non-specific autoimmune manifestations and/or autoantibodies, including antinuclear antibodies and anti-dsDNA. As a result, the diagnosis of a number of systemic or organic disorders, most notably Behc¸ et’s disease, Crohn’s disease, and sometimes even systemic lupus, has been corrected to HA20 by molecular research for a heterozygous mutation with functional deficiency of TNFAIP3. Although the first signs of the disease often appear in the first years of life, the diagnosis is often made in adulthood and requires the involvement of both paediatric and adult physicians. TreatmentforHA20 isnot codifiedandrelies onconventional or biologicalimmunomodulators and immunosuppressants adapted to the patient’s symptomatology. This review highlights the enormous diagnostic challenges in this autoinflammatory disease.

© 2023 Société Nationale Française de Médecine Interne (SNFMI). Publié par Elsevier Masson SAS. Tous droits réservés.