Modeling the Early Stages of Autoimmunity Through the Study of Immunological Thrombocytopenic Purpura and Juvenile Lupus

N/ANot Yet RecruitingNCT07680010

University Hospital, Bordeaux105 enrolled

Overview

Immunologic thrombocytopenic purpura (ITP) in children is a pre-lupus condition if associated with the presence of anti-nuclear antibodies (ANA), providing a unique model for understanding the natural history of autoimmunity, particularly that of systemic lupus erythematosus (SLE). The investigators will describe the shared and/or unique immunological pathways involved at diagnosis in 70 children with ITP and in 20 children with SLE, and compare them between ITP-ANA- (more often transient), ITP-ANA+ (pre-lupus condition, more often persistent) and SLE

The development of an autoimmune disease (AID) requires several years. In systemic lupus erythematosus (SLE), anti-nuclear antibodies (ANA) appear several years before the onset of the disease. However, it is difficult to identify the early mechanisms of autoimmunity in humans as most patients' samples are obtained at the time of diagnosis. The investigators hypothesize that immune thrombocytopenic purpura (ITP) in children provides a unique model for understanding the initial mechanisms leading to autoimmunity. Children with ITP have common immune system dysfunctions leading to the production of anti-platelet antibodies. However, despite this supposedly common dysfunction, the course and degree of loss of tolerance of the immune system are very heterogeneous: the disease is transient in 75 to 80% of cases, and 15 to 20% of children with ITP have ANA and their course is usually persistent or chronic. This subgroup of children with hematological AID, ITP ANA+ meets the criteria for a broader form of AID: pre-lupus. The investigators have recently shown that 16% of these children with pre-lupus / ITP-ANA+ progressed to complete SLE within a median of 3.8 years. Why do some children have transient or persistent ITP? limited or systemic ITP? The investigators aim to describe the shared and/or unique immunological pathways involved at diagnosis in children with ITP ANA- (transient or persistent), with ITP ANA+ (pre-lupus condition, transient or persistent), and in patients with SLE (persistent by definition) In this exploratory, prospective, bi-centric cohort study, the investigators will include 70 children with ITP and 20 children with SLE newly diagnosed, over 36 months with a 3-month follow-up for children with ITP-ANA- and SLE and a 48-month follow-up for children with ITP-ANA+. ANA positivity will be defined by a titer ≥ 1/160. Blood samples will be collected at inclusion and at 3 months (bio-collection), and further each 6 months for children with ITP-ANA+. ITP status will be defined at 3 months: transient or persistent. The investigators will analyze the signaling pathways (B and T lymphocytes, cytokines, disruption of tolerance and inactivation of X) involved in these different pathophysiological distinct subgroups

Interventions

Blood sampling baseline and M3PROCEDURE

Blood sampling is a routine biological procedure performed under the same conditions as during a follow-up consultation.

Monitoring for SLEOTHER

Monitoring for Systemic Lupus Erythematosus according to SLICC 2012 classification criteria

Procedure/Surgery: Blood sampling baseline and M3 then each 6 months until 48 monthsPROCEDURE

Blood sampling is a routine biological procedure performed under the same conditions as during a follow-up consultation.

moniktoring for SLE : baseline and M3 then each 6 months until 48 monthsOTHER

Monitoring for Systemic Lupus Erythematosus according to SLICC 2012 classification criteria

Eligibility

Sex: ALLMin age: 1 YearMax age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

* Inclusion criteria: * For patients : * Child or adolescent with newly diagnosed ITP or SLE according to the specific definitions of ITP or SLE, prior to any treatment, * Over 1 and under 18 years of age at diagnosis, weighing more than 7 kg. * Written consent from parents or guardians, * Patient affiliated to a social security scheme. * For controls : * Over 1 and under 18 years of age at diagnosis, weighing more than 7 kg. * Follow-up in the day hospital at the Bordeaux University Hospital, for a condition that does not affect the immune system * Matched on age, * Written consent from parents or guardians, * Patient affiliated to a social security scheme * Exclusion criteria: * For patients : * ITP secondary to a known cause: previous or concomitant immune deficiency, bone marrow or organ transplantation, other autoimmune disease, Evans syndrome (autoimmune hemolytic anemia or autoimmune neutropenia present at ITP diagnosis) or cancer with immunosuppressive therapy. * Treatment with immunomodulation or immunosuppressants (including immunoglobulins, corticoids, hydroxychloroquine), started prior to inclusion (day of sampling). * Pregnant women, women in labour and breastfeeding women * For controls : * Suffering from an immunological disease, * Infection within fifteen days prior to inclusion, * Immunomodulatory therapy. * Pregnant women, women in labour and breastfeeding women

Outcomes

Primary Outcomes

Characterisation of B and T lymphocyte populations

Characterisation of B and T lymphocyte populations through the study of surface markers and intracellular factors. This panel will, in particular, enable the identification of effector B cells such as plasma blasts, subsets of auto-reactive 'double-negative' (DN) B cells, regulatory B cells, and follicular T helper (Tfh) and peripheral extra-follicular T helper (Tph) cells. Each population will be compared between the patients and the control group.

Time frame: Baseline, Month 3 visit.

Plasma markers

Soluble cytokines and factors regulating B-cell survival (BAFF, TACI, IL-6, IL-12p70, IFN-γ, IFN-β, TGF-β, and the IFN-regulated chemokine CXCL10) will be quantified in plasma using a customised multiplex Luminex assay. Interferon alpha levels will be specifically measured using ultra-sensitive SIMOA (Single Molecule Array) technology.

Time frame: Baseline, Month 3 visit.

Plasma markers

Circulating plasma autoantigens - soluble P-selectin and CD40L derived from platelet activation - will be measured by ELISA. The levels of circulating and mitochondrial DNA will be measured by quantitative RT-PCR in collaboration with V. Sisirak (DR CNRS, Immunoconcept). The overall activity of plasma DNases will be determined by an in vitro DNA degradation assay.

Time frame: Baseline, Month 3 visit.

Secondary Outcomes

Single-cell transcriptomic analysis

Using single-cell RNA sequencing, a single-cell transcriptomic analysis, we will be able to quantify and analyse the transcriptomes of lymphocytes B This will enable us to characterise heterogeneous cell populations, as well as to reconstruct cell development pathways and model transcriptomic dynamics. This technique will enable the modelling of signalling pathways involving B lymphocytes in the subgroup of ITP patients with positive AAN titres, and the development of an algorithm and a mathematical model of the progression of these cellular and molecular markers

Time frame: Baseline, Month 3 visit , Month 6 visit , Month 12 visit, Month 18 visit, Month 24 visit , Month 30 visit, Month 36 visit, Month 42 visit and Month 48 visit.

Single cell epigenetic analysis

Using single-cell ATAC sequencing, we will be able to analyse the regions of DNA accessible to the transcription machinery. This will enable us to identify regulatory programmes such as signalling pathways. The analysis will also reveal heterogeneity amongst B-cell subpopulations, which may respond differently to signals. This will provide insight into the epigenetic status of genes, or at least into which factors regulate this signalling pathway and how the cell adjusts its response depending on its situation or stage of maturity, or on the signal itself.

Time frame: Baseline, Month 3 visit , Month 6 visit , Month 12 visit, Month 18 visit, Month 24 visit , Month 30 visit, Month 36 visit, Month 42 visit and Month 48 visit.

Modeling the Early Stages of Autoimmunity Through the Study of Immunological Thrombocytopenic Purpura and Juvenile Lupus

Overview

Conditions

Interventions

Eligibility

Locations (2)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts