Thymus Transplant for

Thymus Transplantation for Infants with complete Di George

Syndrome

Graham Davies – Consultant Immunologist

Evey Howley Immunology CNS – Thymus Transplant

What is complete Di George syndrome and other associated Immuno-deficient conditions

Why is a Thymus important for effective immunity?

Thymus Transplant pathway at GOSH

Outcome and Mortality post Transplant

Meet our families

Future for Thymus Transplant

Summary

Stem cells

Pre T cells

“educated” in

thymus emerge

into blood as

naïve T cells

B

Blood

Bone marrow

T

NK

Thymus Stem cells in the

bone marrow make

all the cells in the

blood

Pre T

Di George Syndrome is a genetic primary immune deficiency (approx 1 in 4000). In most cases Di George Syndrome results from chromosomal 22q.11 deletion

Heart defects Endocrine problems such as hypocalcaemia,

hypoparathyroidism and hypothyroidism Low set and smaller ears Slanted small eyes, hooded eyelids Small jaw, mouth Small head Cleft lip/palate Absent or non- functioning thymus gland = Complete Di

George syndrome

What is Di George syndrome?

Charge Syndrome =

C – Coloboma of the eye which causes visual impairment- a hole in one of the structures of the eye

H – Heart defects of differing severities

A – Atresia of the choanae – narrowing or blocking of the passage that go from the nose to the throat

R - Poor growth or development

G – Genital and/or urinary abnormalities

E – Ear abnormalities causing hearing impairment

PAX-1 genetic mutation

Thymic aplasia resulting in Hypoparathyroidism, Omenn's syndrome, SCID

Fetal toxin exposure – Poorly controlled Diabetes in 1st Trimester

Other conditions associated with Di George phenotype

Rare inherited disease caused by autosomal recessive loss-of-function mutations in FOXN1 gene

A mutation in this gene has been associated with T-cell immunodeficiency, resulting from Athymia Congenital alopecia universalis

Nail dystrophy

This gene encodes a transcription factor essential for the development of the thymus

What is FOXN-1?

Courtesy of Louise Markert - unpublished

0

200

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1400

CD3

CD4

naïve CD4

Survival of 31 untreated patients w ith Complete

DiGeorge

0

0.1

0.2

0.3

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1

0 0.5 1 1.5 2

Years

Why is a thymus gland important?

A T-cell or T-lymphocyte is a type of WBC

Essential for the immune system function

Scans for abnormal cells/infections

Recognise what is self and what is foreign

Two types:

CytotoxicT cells (CD8 +) scan and destroy

Helper T cells (CD4 +) cells activate an immune response

What is the Function of a T cell ?

Louise Markert Clin Immunol. 2010 135:236

Thymus Transplantation

Thymus Transplant at GOSH

Inclusion

Complete athymia

Features of DGS including at least one of:

22q.11 deletion

Hypoparathyroidism

Heart defect

CHARGE

Exclusion

Previous HSCT - update

Heart surgery planned within 3 months

Ventilator dependent

Severe muscle wasting

HIV infection

CMV infection - update

First transplant at GOSH took place May 2009.

Infants are referred to GOSH, athymia confirmed

Identify Thymus, via screening Cardiac surgery lists

Donors are matched by blood group (ABO) only - no tissue matching at this time

Initial screened by age (<1year) and pre-existing diagnosis – 22q.11 deletion, Trisomy 21, Immunodeficiency

Consent for Thymus donation and viral screening of baby and mother

A 2nd Thymus is often collected within days in case of failed screening 1st

Thymus Transplant at GOSH

Selecting Donor thymuses

Age <12 months

ABO compatible

Not MHC matched

No chromosomal defect (trisomy, 22q etc)

No known infection

No previous cardiac surgery

109 thymuses cultured for 37 Tx

Thymus in the Laboratory

2

2

2

1

2 1

4

2

2

1

1

1

10

1

1

1 1

Wider Multidisciplinary Team!

Ciclosporin A

ATG 2mg/kg x3 doses D -3 -2 -1

Methylprednisolone

Prednisolone

Immunoglobulin continue

+/- anti-biotics

+/- anti-fungals

+/- anti-virals

Pre Conditioning & Prophylaxis options

Around a 3inch incision is

made into both thighs, down to

the muscle

Approx. 15 slices per thigh

The surgeon creates a small hole for each slice within the

infants muscle

The thigh muscle creates an effective replica home environment

Procedure

Wound care post transplant - observe PEWS, fluid balances (Ca), documentation Pain relief Continue isolation Continue IVIG and other prescribed treatments Regular blood tests - Lymphocyte Sub Sets to monitor T

Cell function, viral loads, thyroid stimulation Respond to symptoms as they occur – CTLs, GVHD Continue support & education with parents Repatriate 3 months Biopsy

Post Transplant

Outcomes …

cDGS Patients transplanted -34 (35Tx)

Median age 8 mo (2-26)

32 Hypoparathyroid

16 Major cardiac defect

3 Hypothyroid

22 Atypical picture

9/12 CHARGE

CD3 120 -1250

No naïve T cells

Absent/subnormal PHA

1 Mat Engraftment

1TA GVHD

22Q.11 delCHARGE

TBX1 mut

Mat diabetesUnknown

DGS

ATG

Yes, 19No, 11

Withheld,4

Significant infections before TTx – 19 patients

Gastrointestinal Rotavirus 8 Norovirus 3 Sapovirus 2 C. difficile 2

Respiratory RSV 2 Parainfluenza 1 Corona virus 1 Boccavirus 1

Systemic CMV 1 Adenovirus 1 HHV6 1

Local mycobacterial BCG 3 NTM sternal abscess

Outcomes

1 lost graft

Septic shock

Developed B NHL

Re-transplanted after 1 year

8 deaths

7 early

3 patients long term poor reconstitution

1 on long term immunosuppression

Reconstitution

PTH

Chance Parathyroid Transplant ( 1 patient)

Davies et al 2019

Reconstitution of Parathyroid Function in one patient

Complications: Inflammatory Reconstitution syndrome (IRS)

Mycobacteria driven (3pts) 2 BCG, 1 NTM sternal abscess All 3 have low total T cell numbers but good % naïve and good

TRECs

Enteropathy driven by infections (6 pts) Rota/Noro/ Adeno/ C.diff

Skin disease HHV6 ( 1patient)

No identified driver skin +/or gut (3pts) Systemic IRS – fevers, high CRP, capillary leak

Summary Immune reconstitution from 6 months

Thymic emigrants with diverse repertoire, but usually not normal numbers

Possibly better reconstitution with some Class 2 MHC matching

Mortality 9/37 – infection commonest cause

Inflammatory disease Related to preceding infections especially GI tract & BCG

Unknown trigger

Not related to ATG usage or to MHC matching

Need better peri-reconstitution management

Autoimmunity Most commonly thyroid

Possibly lessened by some MHC 2 matching

Families met along the way …

Family Participation

Donor for

research

Donor for

transplant

Thymus Transplant Recipient

2 families, 1 transplant

Recipient – AO

Infection – CMV

Compassionate use

Ethics

Family understanding

Altruism

Isolation and separation

Uncertainty

Donor

New baby

Timing of the approach

Protecting their own priority

Right amount of contact

CMV and Outcome

CK14

CD1a

AO

As you know, after the transplantation my wife and daughter stayed in an isolated room in the

hospital. The isolated rooms in Turkey are not same as the ones in your hospital. My wife could not exit the hospital, while I was not able to see my daughter. My bad mood and workload also avoided me from writing you earlier.

At last, we left the hospital and moved home three months ago. The progress in AO is amazing for

us. AO is very happy, she smiles and makes different sounds all the day. Last week, she learned to throw a kiss. She smiles unless we try to feed her.

We still feed her with nasogastric tube. We cannot feed her from mouth. She does not accept anything other than food with rice flour. She hates the spoon. She pretend coughing or sleeping when we approach her with spoon, even the it is empty. She is completely an actress.

She uses her hands but do not step on the ground properly. Our physical therapy and rehabilitation doctor tells that AO was in bed for a long time, so this is normal and will get better with time. She showed us some exercises, we practice them and try to strengthen her legs and feet.

We are happy and full of hope for the future

AO at home

Meet our Family’s

Meet Our Family’s

Explore HLA matching – Frozen Thymus tissue bank

Explore autoimmune phenomena

Effect of newborn screening for SCID

Newly designed thymus transplant pathway information booklets for families

Deliver European Family day

Explore family experience for both donor and recipient

Future

Acknowledgements

Jeans for Genes Campaign

Mason Medical Research Trust

Austen Worth Matthew Buckland Alexandra Kreins Kimberley Gilmour Melissa Cheung Paul Kelly Irene Obiri-Yeboa Clare Marriot Neil Sebire Dyanne Rampling Joe Curry Stefano Giuliani Winnie Ip Stuart Adams Susanne Kricke Eleanor Watt Giovanna Lucchini Maaike Kusters Susan Ross Anna Furmanski Tessa Crompton Athina Soragia –Gzaki Ben Margetts Adrian Thrasher

Malgorzata Pac, Warsaw Jolanta Bernatoniene, Bristol Kim Neuling, Coventry Ronald Bremner, Birmingham Hans-Christian Erichsen, Oslo Marianne Iversen, Copenhagen Mike Browning, Leicester Tiia Voor,Tartu Mihaela Bataneant, Timisoara Ronan Leahy, Dublin Despina Moshous, Paris Manfred Honig, Florence Junghans,Ulm Tim Niehaus, Gregor Duckers, Krefeld Silvana Martino, Torino Leena Kainulainen, Turku Mervi Taskinen, Helsinki Fulvio Porta, Brescia David Pace, Malta Susanne Matthes, Anita Lawitschka, Vienna Andrew Gennery, Newcastle Olov Ekwall, Stockholm Anna Sediva, Prague Fiona Shackley, Sheffield Kamile Aydan, Ankara Gasper Markelj, Ljubyana Peter Ciznar, Bratislava Stephen Jolles, Cardiff.

CO-MANAGING CLINICIANS

All the parents and families