Pediatric Vasculitis Lessons from ARChiVe

David CabralBritish Columbia Children’s Hospital

Vancouver, CANADA

A Registry of Childhood Vasculitis

Learning objectives

• Focus on pediatric AAV & PAN: differences between children & adults in -

➢Classification➢Disease presentation➢Outcome ➢Treatment

• Opportunities for biological study in kids

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Patient presents to ED

• 5 year-old first nations girl - chronic mild asthma; father had JIA

• Swollen feet; ankle pain (arthritis) & rash

• Microscopic hematuria/proteinuria; normal creatinine

➢followed 2-weekly in resident O/P clinic

IgA Vasculitis (HSP)!

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Two-weekly HSP follow-up

• Initial improvements, then slow worsening

• 6w acute worsening “unwell”

– spreading rash, facial puffiness, hypertension

– urine output; > 100 rbc; casts+

• Admitted to ICU oliguric renal failure – (K+ 6.5, creatinine >700; PCR 700)

➢Hemodialysis,

➢BP control

➢Kidney biopsy➢ help treatment decisions

➢ differential diagnosis

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Differential diagnosis of IgAV / HSP?

• Infection• TTP• PSGN• SLE• FMF• Other vasculitis• DADA2 in the young?

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Histopathology Dominant IgA immunofluorescenceIncreased mesangiumMesangial electron dense deposits

Purpura / petechiae*- LL predominance PLUS one of

• Arthritis* /arthralgia• Abdominal pain• Renal involvement*• Characteristic histopathology

Criteria (EULAR/PRINTO /PRES )

For IgA Vasculitis (HSP)

Actual Histopathology

REPORT: Focal segmental pauci-immune Glomerulonephritis with 50% crescents and associated tubular injury

PLUS p- / MPO ANCA

DIAGNOSIS: Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV)

• Is it common, do other kids get it?

• What type of vasculitis? Does it matter?

• How do we treat & is it dangerous?

• How long do we need to treat?

• What is the outcome?

• Is it the same as adults?

…. from family &/or doctors

➢Classification➢Disease presentation➢Outcome ➢Treatment

• Do they differ?

– Intrinsically!

– Effects of disease and treatment differ in a growing child with immature immune system!

• Kids provide opportunity for biological discovery

– Preponderent genetic influence

– Less co-morbidity

Adult vs pediatric vasculitis….should they be studied independently?

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• Case reports / case series

• No pediatric RCT

• ‘Adapted’ adult data

• Expert pediatric consensus

Wilkinson et al. J Rheumatol 2007

Chronic Childhood Vasculitis is rare! Where do we get answers to these questions?

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A Registry for Childhood Vasculitis

Pediatric Vasculitis InitiativeA CIHR Emerging Team Grant in Rare Disease (2012)

2006

2013

ARChiVe /Pedvas: Cumulative data & samples

48 sites, 10 countries_______________________________________________________________

( )

2012 PedVas

biosamples &Follow-up data

Follow up: n=107

With Biosamples: n=165(RNA, DNA, serum, plasma, urine - 21 sites, 7 countries)

Primary systemic vasculitisHeterogeneous group of syndromes

_________________________________________

Single organ vasculitis

PACNS

Cutaneous Vascultiis

*

*

Multifactorial / polygenic

Autoimmune / Inflammatory

Differing histopathology

Few to multiple organs

Mild to rapidly fatal

Acute / chronic

Small / medium / large vessels

- Several disease syndromes

- overlapping presentations *

Figure adapted from: Watts & Dharmapalaiah (2012). Arthritis Research UK Topical Reviews.

…. Classification - why?

To define clinically homogeneous groups:

• to define disease course & outcome

• to prognosticate

• to participate in clinical studies (RCTs)

• May define biological uniqueness !

➢ Biomarker discovery

➢ etiological discovery

➢ Mechanisms

How do we classify childhood vasculitis?

1990: ACR criteria• 33-66% children with WG (GPA) unclassifiable (1996)*

2004: The pediatric classification initiative

2010: Pediatric-specific vasculitis classification criteria EULAR/PRINTO/PRES criteria

2012: Revised International Chapel Hill Consensus Conference: Nomenclature of Vasculitides (CHCC 2)

2017: DCVAS provisional criteria new for GPA. An collaborative transatlantic endeavor

*J Rheumatol 1996 23(11):1981-7; J Rheumatol 1996 23(11):1968-74; J Rheumatol 2007 34(1):224-6

Ankara 2008______________________________

Pediatric Classification criteria for GPA EULAR/PRINTO/PRES Criteria

1. Nasal / sinus inflammation

2. Abnormal radiograph or CT of chest

3. Abnormal urinalysis (hematuria +/or proteinuria)

4. Granulomatous inflammation on biopsy/ (necrotizing pauci-immune GN

5. Subglottic, tracheal, endobronchial stenosis

6. PR3-ANCA or C-ANCA staining

Classification as GPA requires 3 of above criteria

Ozen et al, ARD 2010

1990 ACR

Criteria (n=87)

EULAR/PRINTO/ PRES

criteria (n=98)

843

14

101 of 155 classified as GPA

one way or another

________________________________________________________

MD Diagnosis Sens Spec

1990 ACR 69% 67%

2008 EULAR/PRINTO/PRES 77% 61%

Uribe, A. J Rheumatol 2012

ACR or EULAR/PRINTO/PRES classification criteria for GPAapplied to 155 patients with chronic Sm-Med ves vasc.

33 also

MPA

1990 ACR

Criteria (n=87)

EULAR/PRINTO/ PRES

criteria (n=98)

843

14

5 also

MPA

2 also

MPA

40 of 101 are also MPA

by CHCC definition

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MD Diagnosis Sens Spec

1990 ACR 69% 67%

2008 EULAR/PRINTO/PRES 77% 61%

Uribe, A. J Rheumatol 2012

ACR or EULAR/PRINTO/PRES classification criteria for GPAapplied to 155 patients with chronic Sm-Med ves vasc.

CHCC definition of MPA

applied to patient groups

Differences between pediatric GPA and MPA?

GPA

n=183

MPA

n=48

Med age at diagnosis yrs 14 12

Female % 62 73

Kidney disease % 83 55

More severe

Pulmonary disease % 74

More severe

44

GI symptoms % 36 58

MPO / p –ANCA % 26 55

PR3 / c – ANCA % 67 17

Cabral et al. A&R, 2016

21% childhood AAV unclassifiable as GPA, MPA or EGPA

• GWAS: N = 2687 patients, 7650 controls Lyons et al., NEJM, 2012

Key conclusions: genetic markers of AAV

➢ 4 loci associated with AAV➢ 6 loci specific to either GPA or MPA➢ Association with ANCA -type stronger than ‘phenotype’

Biological basis for vasculitis types?Genetically distinct subsets within adult AAV

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Biological basis for vasculitis types?Transcriptomic biomarker discovery in kids!__________________________________________________

30 patients provided clinical data & samples for RNA sequencing

ANCA associated vasculitis (AAV) 20

GPA 16

MPA 4

Unclassified Vasculitis 8

Polyarteritis nodosa (PAN) 2

Erin E. Gill, Robert Hancock Lab. UBC

GPA-like cluster (n=13; 8 F)

• 9 GPA; 4 UCV

• Anti- PR3: MPO = 70:30

• genes involved innate immunity; & predominantly neutrophil degranulation

MPA-like cluster (n=14; 9F)

• 4 MPA; 5 GPA; 2 PAN; 3 UCV

• Anti- PR3: MPO = 45:55

• genes involved adaptive immunity; & T-Cell activation

Outlier cluster: No pattern 2GPA; one UCV 22

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Erin E. Gill, Robert Hancock Lab. UBC

Different gene expression patterns hierarchical clustering to 3 groups

RNA-Seq Data unbiased analysis:3809 differentially expressed genes

Different gene expression patterns in GPA /MPA ~like groups

As few as 20 differentially expressed genes may accurately classify individuals to GPA -/ MPA- like groups

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Evidence of neutrophil activation in GPA

178 (8%) of 2,217 highly expressed genes in GPA-like cluster involved in neutrophil degranulation; genes depicted here with NetworkAnalyst.

The most highly connected genes among these included MAPK1 and MAPK14, the heatshock protein HSPA1B, PSEN1, and polyubiquitin-C (UBC)

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Evidence of T cell activation in MPA

CD4 and genes in MHCII pathway (ie towards CD4 T cell activation) highly expressed in MPA-like samples

Normalized read counts of T cell subtype-specific transcription factors were used to determine relative ratios of different T cell populations in MPA vs GPA

Individuals in the MPA-like cluster had a slightly lower ratio of Th1:Th2 cells (P = 0.038) than individuals in the GPA-like cluster, and a much higher ratio of Th2:all T cells (p= 3.0E-06).

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Classifying vasculitis!The Indian fable of the elephant & 6 blind men

“…it’s a pillar”

“…a rope”

“..a tree branch”

“.. a hand fan”

“…a huge wall”

“ .. a solid pipe”

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Is pediatric & adult GPA the same at onset?

Children**n=183

Adults*n=55-80

Peak incidence yrs 13.5 55

Female % 62 30-50

Constitutional features % 88 60

Kidney disease % 83 55

Pulmonary disease % 74 60

ENT disease %- subglottic stenosis %

7010

6512

*Koldingsnes A&R, 2000; Mahr A&R, 2008; Stone NEJM, 2010; **Cabral et al; A&R 2016

Pediatric GPA more severe, more organs affected

….treatment

• preventing relapses

• limit accumulating disease/treatment damage

- Use evidence-based adult strategies & guidelines!

- What do we actually do in pediatrics?

Are the treatments dangerous?Children no longer die soon after diagnosis.

• Mortality reduced with cyclophosphamide & steroids

• Treatment risks (short & long term)

- Life-threatening infection*

- Malignancy

- Cardiovascular disease

- Fragile bones

- Infertility*

- Interrupted growth and development*

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Reducing the treatment risks.Evidence based treatment strategies in adults

• Limit cyclophosphamide to remission induction - Never >6 m

• Less toxic drugs for remission maintenance - MTX, AZA, MMF

• Milder less toxic drugs from outset - MTX, AZA, MMF

• Alternatives to CYC - Rituximab, infliximab, tociluzimab, etc

• Limit corticosteroid duration - Minimum to none after 6-12m

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Treatment of severe GPA/MPA

INDUCTION MAINTENANCE

Cyclophosphamide

• IV: 15mg/kg (d1,14,28 ->q3wk)

• Oral: 2mg/kg/d

3-6 months (max 6m)

DMARD alternatives -

• AZATHIOPRINE 2 mg/kg/d

• METHOTREXATE 0.3 mg/kg/wk

• MYCOPHENOLATE MOFETIL 2g/d

• LEFLUNOMIDE 20 mg/d

? Plasmapheresis ??

+ Cotrimoxazole (prophylaxis against P. Jiroveci & ENT relapse)

Or Rituximab Or Rituximab

> 24 months …??

R+ Corticosteroids

J Rheumatol 2016;43:97-120

How do we treat severe pediatric GPA/MPA?

Treatment Stage

Survey PHYSICIANS

N=142

Archive PATIENTS

N=231

Remission Induction

Cyclophosphamide % 66 76

Rituximab % 31 12

MTX / AZA / MMF % 10

Remission Maintenance

Azathioprine 45 45Methotrexate 23 24Mycophenolate 18 14Rituximab 11 10Cyclophosphamide 10

Cabral et al. A&R, 2016; Westwell-Roper et al. PROJ 2017

For how long will she need medicines?Duration of Maintenance (physician survey)

Duration (m) %

Corticosteroids

24 4

18 6

12 40

6 39

Immunosuppressant

36 14

24 46

18 19

12 13

PVAS & PGA = 0

________________________________________________

Westwell-Roper et al. PROJ 2017

For how long will she need medicines?Duration of Maintenance (physician survey)

Duration (m) %

Corticosteroids

24 4

18 6

12 40

6 39

Immunosuppressant

36 14

24 46

18 19

12 13

PVAS & PGA = 0

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Westwell-Roper et al. PROJ 2017

Preliminary Data: Biological

Measures of Disease Activity

Dirk Foell Lab, MunsterKelly Brown Lab, Vancouver

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Preliminary data: vasculitis remains active following treatment and when clinical measures suggest no activity

Erin E. Gill, Robert Hancock Lab, Vancouver

…outcomes• What do we know in pediatrics?

• What do we need to know?

Early (12m) Outcome of 105 children with AAVRemissions, relapses & tracking disease activity

• Majority renal (78%) +/or pulmonary disease (80%)

• 49% inactive disease post-induction (PVAS=0)

• 64% had inactive disease at 12m (PVAS=0)

• 42% achieved remission at 12m (PVAS=0, 0+Pred)

• A large proportion (63%) have damage by 12m

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Morishita et al; A & R 2017

Early (12m) Outcome of 105 children with AAVHospitalizations, morbidity & mortality

Damage as reported by pediatric-adapted VDI.

- 66 (63%) > 1 item at 12m (Med VDI = 1; range 0-6)

43 (41%) patients had 80 hospitalizations- 46% disease flares

- 15% other disease related (investigation, rehab)

- 16% infections

- 5% treatment / medication related adverse events

- 18% unrelated

12 (11%) patients ESRD; 2 renal transplants

No deaths

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Morishita et al; A & R 2017

Renal prognosis at one year

58% moderately impaired renal function at TOD

• 37% have persisting impairment.

Patients with renal failure at TOD unlikely to recover normal renal function

• 50% dialysis dependent or transplanted by 12m

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What do we need to know

Pediatric specific evidence-base data on:

• Long term outcome of Ped – AAV

• Predictors of outcome

• Efficacy CYC versus RTX

• Short, med, long term drug specific toxicities

• Better measures of disease activity / inactivity

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Shifting gears

Polyarteritis Nodosa (PAN)

Necrotising vasculitis

• Medium-Small arteries (c.f. MPA)

• fibrinoid necrosis

• Micro-aneurysms

• ANCA negative

• Idiopathic, or

- infection associated

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Classification Criteria (EULAR/PRINTO /PRES) for Childhood Polyarteritis Nodosa

Involvement of small-medium arteries on

Histopathology (necrotising vasculitis)OR

Angiogram (aneurysm/stenosis/occlusion)

PLUS one of

1. Skin involvement (livedo /nodules /infarcts)

2. Myalgia or muscle tenderness

3. Hypertension

4. Peripheral Neuropathy (sensory / mononeuritismultiplex)

5. Renal involvement

Loss of function variants in ADA2 found to be associated with Polyarteritis Nodosa

NEJM, 2014

What is Deficiency of adenosine deaminase 2

• Monogenic (AR) vasculitis syndrome

– Loss of function mutation CECR1 gene

• Clinical overlap with PAN (MVV)

• Clinical manifestations:

– Early-onset inflammatory manifestations

– Livedo reticularis

– Recurrent strokes

– Hematological manifestations• Hypo-g globulinemia• red cells, neutrophils, platelets down

Navon et al. N Engl J Med 370(10): 921-931 (2014).

__________________________________________________________________________

• PAN (Extent / severity dependent)

– Corticosteroids (i.e. Prednisone)

– Cyclophosphamide /azathioprine /methotrexate

• DADA2

– limited response to traditional PAN therapy– Better response to anti-TNF therapies– anti-TNF prevents strokes

How to ensure timely diagnosis of DADA2 to ensure targeted therapy & improved outcome?

PAN versus DADA2 therapy_______________________________________

AIM: Screen patients in the PedVasregistry for variants in ADA2

Screening criteria (must meet one criterion):

Diagnosis

• Diagnosed as PAN

• Unclassifiable phenotype

Early onset disease

• < 5 years of age

Central nervous system involvement

• Stroke

60 patients met this criteria for screening by– targeted Sanger sequencing

– adenosine deaminase activity testing

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PedVas patients with rare ADA2 mutations

ID Ethnicity SexAge at

Onset

Age at

Diag

Initial

DiagnosisADA2 Mutation (CDS)

P1 South Asian F 11y 12y PAN c.[139G>C];[139G>C]

P2 South Asian F 11y 12y PAN c.[139G>A];[139G>A]

P3 East Asian M 16y 16y UCV c.[25C>T];[140G>C]

P4 South Asian M 11y 12y PAN c.[1069G>A];[1069G>A]

P5 Caucasian F 1 wk NA Undiagnosed c.[1052T>A];[1052T>A]

P6 Caucasian F 10 mo 3y Undiagnosed c.[1052T>A];[1052T>A]

P7 East Asian F 4y 4y PAN c.[139G>A];[139G>A]

P8 South Asian F 3y 5y GPANo identified variants in

coding / splice-site regions

P9 Caucasian F 6 mo 8 mo UCV c.[139G>C]; deletion

P10 South Asian M 11y 11y cPAN c.927G>A

P11 Caucasian F 2y NA Undiagnosed c.1252G>T

• Arg9Trp (c.25C>T) and Ala357Thr (c.1069G>A) novel assoc. with DADA2• Leu351Gln (c.1052>A) novel variant

Patients screened by ADA2 enzyme levels____________________________________________________________

Clinical manifestations of DADA2 patientsID Fever Cutaneous Nervous System Other Organ Systems Vascular Imaging

Hypo-g-glob-ulinemia

P1 NoNodules;

Livedo reticularisNone

Blurred vision;Anemia

Microaneurysms in hepatic & splenic artery

Notdone

P2 YesNodules;

Diffuse digital swellingMotor mononeuritis

multiplexOral ulcers;

Abdominal painMicroaneurysms in splanchnic vessels

Not done

P3 YesPainful subcutaneous

nodulesMeningitis/encephalitis

Brainstem infarctNone No abnormal findings

Not done

P4 YesUlcers

Livedo reticularis;Superficial infarctions

Midbrain infarcts Blurred visionAneurysms in renal,

splanchnic & vertebral arteries

Low IgM

P5 YesLivedo racemosa vs cutis

marmorataDiffuse cerebral

atrophy

Oral ulcers;Bloody diarrhea;

Perforated bowel;Anemia; Neutropenia

No abnormal findings Low IgM

P6 Yes NoneStroke;

Cranial nerve involvement

Blurred vision; Neutropenia

Chronic liver disease;Perforated bowel;

No abnormal findings Low IgM

P7 YesSubcutaneous edema;

Nodules

Stroke;Cranial nerve involvement

Blurred visionRestricted diffusion on left

thalamusLow IgM

P8 YesSubcutaneous edema;

Polymorphous rashDecreased tendon

reflexes

Oral ulcers; Anal fissures;

Saddle nose deformity;Glomerulonephritis

No vascular imaging performed

Normal

P9 YesLivedo reticularis;

Raynaud’s phenomenon

Oculomotor nerve involvement;

Lacunar cerebral infarctions

Oculomotor palsy; Ileitis;

Splenic infarction;Hypertension

Decreased diameter of thoracic aorta and right

radial artery; Irregularities of the abdominal aorta

Notdone

Summary of ped- DADA2 screening

• 9 of 60 (15%) screened had DADA2

• 8 with bi-allelic variants in ADA2 » 3 novel variants

• Early onset with fever, livedo, stroke/neuro findings » but also 4/9 were over 10» 3 patients south asian; one east Asian

• PAN phenotype predominantly but » GPA» Early onset unexplained inflammatory brain

disease

• 4 of 9 treated with anti-TNF responded well

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Gibson et al. Arthritis and Rheum, 2019).

Screening adult PAN for DADA2Presented ACR 2018 for VCRC (Merkel)

• 117 patients with idiopathic PAN from Vasculitis Clinical Research Consortium PAN cohort (Hep B neg)

• 4 /117 with bi-allelic ADA2 ‘damaging’ variants – 4 others had mono-allele variant (1/4 predicted damaging)

• 5 with low ADA2 enzyme activity

DADA2 with no identified ADA2 variants (peds/adults)

Extended sequencing intronic and non coding regions, modifying alleles, epigenetic modifications, or environmental exposures.

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Overview: about pediatric vasculitis

• Heterogeneity evident between, & within, different syndromes– phenotype, outcome, biology, etc.

• Childhood AAV different to adults and the extent of the differences still to be determined

• Pediatric vasculitis patients provide a unique opportunity for bench research

• Ongoing international, multicenter collaboration is essential.

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Acknowledgements

PedVas / ARChiVe Network

BCCH Clinical Team

Lori Tucker

Ross Petty

Kristin Houghton

Jaime Guzman

Andrea Human

Kelly Brown Lab

Kristen Gibson

Iwona Niemietz

Jordan Chiu

Sara Marrello

Children with vasculitis and their families

PedVas GroupSusanne BenselerDirk FoellColin RossBob HancockRaashid LuqmaniJinko Graham

Kelly BrownKim MorishitaChristoph KesselErin GillMarinka TwiltGuilia AmaroliKristen GibsonAngelyne Rivera