HLA Analysis in Autoimmune Encephalitis and Related Disorders: Part II (ICARE-II)

Immunogenetic Characteristics in Autoimmune Encephalitis and Related Disorders: HLA Analysis: Part II

Autoimmune encephalitis (AE) are characterized by subacute onset of memory deficits, altered mental status or psychiatric symptoms, frequently associated with seizures, inflammatory cerebrospinal fluid and in cases with prominent limbic involvement, typical magnetic resonance imaging. Several autoantibodies (Abs) may be detected in AE, although its detection is not mandatory to establish a diagnosis. These Abs mainly recognize different synaptic and cell-surface proteins in the central nervous system, and are thought to be pathogenic as they alter the normal location or function of its antigens. Paraneoplastic neurological syndromes (PNS) are immune-mediated, remote complications of cancer. The clinical presentation is highly diverse, from central nervous system disorders (limbic encephalitis, cerebellar ataxia) to peripheral neuropathies and neuromuscular junction diseases. Two different kinds of Abs are associated with PNS: a first group known as onconeural Abs, which recognize intracellular antigens and are thought not to be pathogenic; and a second one whose targeted synaptic and cell-surface antigens shared with some non-paraneoplastic AE.

The primary trigger of the immune response is unknown for most of AE. In addition to acquired susceptibility such as herpes simplex encephalitis, genetic predisposition may also be important in the pathogenesis of AE. Human leukocyte antigen (HLA) is the genetic factor most frequently associated with autoimmune diseases, due to its genetic complexity and key role in the adaptive immune response. Others and we already described the HLA haplotypes associated with three types different of AE: anti-leucine-rich glioma inactivated 1 (LGI1), anti-contactin-associated protein-like 2 (CASPR2), and anti-glutamic acid decarboxylase (GAD). Nevertheless, the genetic predisposition of many other AE has not been investigated yet.

Cancer is considered as the trigger of the immune response that lead to PNS development, as the neural antigens recognized by the onconeural Abs are also expressed by tumor cells. Nevertheless, it is still unknown why some patients develop PNS and others do not, even if they present the same histological type of tumor, suggesting that some particular, maybe genetic, characteristics of the patients may play a role in this susceptibility. Furthermore, there is already evidence that, for those neurological diseases that may appear either as PNS or as non-paraneoplastic autoimmune disorder (i.e. Lambert-Eaton myasthenic syndrome), HLA profiles are not the same.

Study Overview

• Status: Recruiting
• Conditions: Autoimmune Encephalitis; Paraneoplastic Neurological Syndrome
• Intervention / Treatment: Genetic: Autoimmune encephalitis and paraneoplastic neurological syndromes

• Study Type: Observational
• Enrollment (Anticipated): 700

Contacts and Locations

• Study Contact: Name: Jerome HONNORAT, MD; Phone Number: +33 4 72 35 78 08; Email: jerome.honnorat@chu-lyon.fr
• Study Contact Backup: Name: Géraldine PICARD, ARC; Phone Number: +33 4 72 35 58 42; Email: geraldine.picard@chu-lyon.fr

Study Locations

• France
  • Bron, France, 69677
    • Recruiting
    • Hôpital neurologique
    • Contact: Jerome HONNORAT, MD; Phone Number: +33 4 72 35 78 08; Email: jerome.honnorat@chu-lyon.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients older than 18 years, having well-characterized anti-neural or anti-glial antibodies in serum and/or CSF detected in our laboratory, presenting with well-defined clinical pictures considered as associated with the aforementioned antibodies by a physician (neurologist) from the French Reference Center, including the presence of cancer in the case of paraneoplastic neurological syndromes; and whose clinical data is stocked at the database of our center.

Description

Inclusion Criteria:

• Presence of well-characterized antibodies in serum or cerebrospinal fluid;
• Clinical picture compatible with the detected antibody based on the literature;
• For PNS, cancer detected and compatible with the detected antibody based on the literature

Exclusion Criteria:

• Absence of complete clinicobiological data.
• Incongruences between antibody-clinics or antibody-cancer

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Autoimmune encephalitis and paraneoplastic neurological syndromes; Patients with well-characterized antibodies against onconeural antigens, synaptic or cell-surface antigens

Genetic: Autoimmune encephalitis and paraneoplastic neurological syndromes; This is a non-interventional study involving biological samples (DNA). Samples are already stored in biobank repositories and collected as part of "good clinical practice" in the diagnostic process of patients with suspected autoimmune encephalitis, meaning that the standard diagnostic and therapeutic approaches will not be altered in the selected study population. Patients have already gave explicit written consent for biological specimens sampling and storage at the "Centre de Ressources Biologiques des Hospices Civils de Lyon" (CRB-HCL)/NeuroBioTec (including tissue, cells or biological fluids) and genetic analysis for research purposes (e.g. involving genes related to the disease for which the patient was followed). Additionally, patients will be informed about the present study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Description of HLA alleles and haplotypes carrier frequencies in autoimmune encephalitis and paraneoplastic neurological syndromes.	Analyze the distribution of all HLA alleles at the level of the main HLA susceptibility loci, HLA A, B, C, DR, DQ and DP in all patients with AE or PNS.	5 years. M1-M24: clinical database review, DNA extraction M25-M36: HLA analysis M37-M60: statistical analysis, combined analysis of genetic and clinical data

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 1, 2021
• Primary Completion (ANTICIPATED): December 31, 2024
• Study Completion (ANTICIPATED): December 31, 2025

Study Registration Dates

• First Submitted: March 26, 2021
• First Submitted That Met QC Criteria: March 29, 2021
• First Posted (ACTUAL): April 1, 2021

Study Record Updates

• Last Update Posted (ACTUAL): April 1, 2021
• Last Update Submitted That Met QC Criteria: March 29, 2021
• Last Verified: March 1, 2021

More Information

Terms related to this study

• Keywords: Autoimmune encephalitis; Paraneoplastic neurological syndromes
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Endocrine System Diseases; Thyroid Diseases; Thyroiditis, Autoimmune; Thyroiditis; Encephalitis; Hashimoto Disease
• Other Study ID Numbers: 69HCL20_0826

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No