EXE-T1D

The EXE-T1D Study is trying to understand why some people develop Type 1 diabetes very early in life.

Type 1 diabetes (T1D) results from destruction of insulin-producing beta cells in the pancreas by the body’s own immune system (autoimmunity). We do not fully understand what causes this type of diabetes and why there is variation in age of onset and severity between people who develop the disease. The aim of this work is to study very unusual people who develop T1D extremely young, as babies under 2 years of age. We think that, for the condition to have developed that early, they must have an unusual or extreme form of autoimmunity.

Studying people with very early-onset diabetes will enable us to look at exactly what goes wrong with the immune system because they have one of the most extreme forms of the disease. We may be able to learn a lot about the disease from a small number of rare individuals. We aim to confirm that they have autoimmune type 1 diabetes and then try to understand how it is possible that they have developed diabetes so young by studying their immune system genes, the function of their immune system, and environmental factors (such as maternal genetics) that may play a role in their development of the disease.

People with diabetes diagnosed under 24 months are very rare and they live all over the world. We will take advantage of the fact that they are usually referred to Exeter for genetic testing. We will also study eligible patients that are referred directly to Professor Oram.  As part of their wider clinical team, we will contact them via their clinician to ask for more information about their diabetes and their family history. We will collect samples to study whether they still make any of their own insulin and whether they make specific antibodies against their beta cells in the pancreas. Separately, we will study their immune system in depth using immune cells isolated from a blood sample. We will then study these cells using cutting edge techniques by Professor Tim Tree at King’s College London, by Professor Bart Roep at City of Hope Hospital, California (USA), and Dr Cate Speake, Benaroya Research Institute, Seattle (USA). Some of these tests have never been used in people of young ages around the world, so an aim of this project will be to develop methods that can be used to study people even if they live far away.

We have secured additional funding to extend the study for a further 3 years (Phase 2) to include recruitment of infants without diabetes, aged 0-6 years, as controls to enable assessment of how the abnormalities found in autoimmune and non-autoimmune diabetes compare to normal early life development of the immune system. Our results so far highlight a successful strategy of identifying and studying extreme T1D presentations, by leveraging Exeter’s role as an international referral centre for neonatal diabetes and KCL’s world leading role as an immune phenotyping core facility. The second phase of this study seeks to move from observation to mechanism, with a goal of proving that defined abnormalities have a causal role in diabetes development, thereby opening the way for trial interventions.

Studying the pathophysiology of EET1D and immune function in patients diagnosed very early will give insights into the development of autoimmunity and predictors of rapid beta cell destruction.

As EET1D is extremely rare (<100 cases identified by genetic testing in the UK), this study falls under the Musketeers’ Memorandum criteria, an NIHR UK Rare Genetic Disease Research Consortium Agreement. This allows provision for coordination and management of the study at a single NHS site, as Exeter forms part of each patient’s NHS team (although routine care will normally be delivered by their local clinician at a remote NHS site). We will identify people with EET1D who are referred to Exeter for genetic testing or referred directly to Professor Oram, and then aim to collect further samples and clinical information. Existing patients (and therefore of varying ages) will be recruited to Study 1, a cross-sectional study of T1D biomarkers, genetics and clinical information. Newly diagnosed patients who are able to give samples closer to diagnosis will be recruited to Study 2, which allows assessment of the immune system and T1D biomarkers optimised for the small blood volumes possible in young infants. Newly diagnosed patients will also contribute their samples and clinical information to the cross-sectional Study 1.

Initial interim analysis found several immunological abnormalities in infants with EET1D. Our analyses also highlighted that little is understood about the normal development of the immune system in early life. Recruitment of controls without diabetes will enable assessment of how the abnormalities found in autoimmune and non-autoimmune diabetes compare to normal early life development of the immune system. As we have sufficient follow-up data from phase 1, we are also able to simplify our study protocol and keep recruitment to study 2 as a single visit without the need for a follow up visit.

The EXE-T1D study will take people with T1D diagnosed before the age of 24 months and compare them to people with T1D diagnosed at more typical ages (1-20 years) and people diagnosed with non-autoimmune diabetes at a similar very young age (children with neonatal diabetes [NDM]), and infants without diabetes matched for age.

EXE-T1D is an observational study organised into two sub-studies:

Study 1: Cross-sectional study of existing patients with EET1D :

Aim: To compare clinical features, beta cell loss (measured by serum/urine C-peptide), islet-specific autoantibodies, T1D risk genes and autoreactive CD8 T cells in people already known to have EET1D and already referred to Exeter for genetic testing or directly to Professor Oram, to those people with T1D diagnosed at older ages (age 1-20 years).

Study 2: Study of newly referred patients :

Aim: To assess immune function (by measuring autoantibodies, autoreactive CD8 T cells and RNAseq of immune genes) at diagnosis and longitudinally in people with newly diagnosed EET1D compared to newly diagnosed monogenic neonatal diabetes.

Primary Objective

The primary objective of the study is to compare beta cell function and islet autoantibodies in EET1D to T1D and NDM, and non-diabetic controls.

Secondary Objectives

The secondary objectives of the study are:

1. To compare genetic and functional markers of autoimmunity in EET1D to T1D and NDM.
2. To develop a robust pathway to identify, recruit and study early-onset diabetes for a prospective protocol for future study and assessment of patients close to diagnosis of diabetes.

Primary Endpoint/Outcome

Serum/urine C-peptide and autoantibodies (IAA, GAD, IA-2, ZnT8) in EET1D compared to T1D and NDM.

Secondary Endpoints/Outcomes

1. Prevalence and frequency of islet specific CD8 T cells in EET1D compared to T1D, NDM and controls.
2. Frequency and phenotype of pro-inflammatory and regulatory T cells in EET1D compared to T1D, NDM and controls.
3. Difference in immune gene expression, as measured by RNAseq in newly diagnosed EET1D v NDM and controls.
4. Association of maternal and paternal non-inherited HLA alleles with EET1D v older onset T1D and NDM.

Study 1:

EET1D

• Aged 0 to 70 years
• Clinical diagnosis of diabetes <24 months (+ evidence of WHO diabetes criteria)

T1D Controls

• Age 0-70 years (matched to above)
• Clinical diagnosis of T1D (diagnosed age 1-20 years)
• Insulin treated from diagnosis.

Monogenic / NDM Controls

• Diagnosis of diabetes <12 months
• Diagnosis of monogenic / NDM (confirmed by Exeter Molecular Genetics Laboratory).

Study 2:

EET1D

• Aged 0 to 24 months at recruitment
• Clinical diagnosis of diabetes <24 months (+ evidence of WHO diabetes criteria); recruited within 12 months of diagnosis.
• Negative genetic test for mutations causing non-autoimmune neonatal diabetes
• Type 1 diabetes genetic risk score >50^thcentile of T1D reference group, or monogenic cause of T1D (e.g. STAT3orFOXP3mutation)

NDM controls

• Diagnosis of diabetes <12 months
• Age 0 to 24 months at recruitment
• Diagnosis of NDM (confirmed by Exeter Molecular Genetics Laboratory).

Non-diabetic controls for Studies 1 and 2

• Aged 0-6 years (The recruitment priority will be children aged under 2 years but to include children aged 2-6 years)
• Attending specified participating hospital sites for elective surgery, including but not limited to: inguinal hernia repair, umbilical/midline hernia repair, orchidopexy, gastrostomy insertion/change, hypospadias repair, cleft palate repair, excision of accessory digit, laryngoscopy, adenoidectomy, tonsillectomy, MRI under general anaesthesia, eye surgery.  Should recruitment be slower than anticipated, we would recruit children with congenital non-immune thyroid disease when they attend paediatric clinic for blood draw.

Study 1:

• Aged >70 years
• No diagnosis of diabetes
• MODY (e.g. caused by HNF1A/HNF4A/HNF1B/GCKmutations), type 2 diabetes or diabetes related to pancreatic insufficiency or syndromic diabetes
• Intercurrent illness at time of sampling for PBMCs (see below).

Study 2:

• Aged >24 months
• Clinical diagnosis of diabetes >24 months
• Intercurrent illness at time of sampling for PBMCs or RNA (see below).

Non-diabetic controls for Studies 1 and 2:

• Aged >6 years
• Diagnosis of diabetes or other autoimmune condition
• Known immunological disorder
• On immunosuppressive medication
• Ongoing infections/sepsis
• Major congenital abnormality or significant systemic illness that may affect the immune system, e. metabolic disease, 22q deletion syndrome
• Recent (within two weeks) febrile illness
• Renal failure.

For PBMC and RNA sampling:  Exclusion for factors that may alter T cell function and RNAseq

Review the following exclusion criteria carefully at time of appointment as some details may have changed since initial contact:

• Recreational drug use(excluding cannabis use more than 1 week prior to blood sampling) – drug abuse may alter T cell function
• Alcohol related illness(excessive alcohol consumption may alter T cell function)
• Renal failure: Creatinine >200 (as may alter T cell function)
• Any other medical condition which, in the opinion of the investigator, would affect the safety of the subject’s participation.

Factors that if temporary would lead to rearrangement of study visit but if long duration, may lead to exclusion subject to the CI’s discretion:

• Pregnant or lactating (as this may limit blood sampling and affect T cell function)
• Any infectious illness within the last 2 weeks if it was a febrile illness, or within 2-3 days if it was non-febrile (as this may activate T cells non-specifically)
• Taking steroids or other immunosuppressive medications (as these may alter T cell function)
• Received any immunoglobulin treatments or blood products in the last 3 months (as these may alter T cell function).