Pathogenesis of the HIVTB associated immune reconstitution inflammatory syndrome

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Pathogenesis of the HIV-TB associated immune
reconstitution inflammatory syndrome
4th IAS, Sydney, July 23rd 2007
Robert J Wilkinson Wellcome Senior Fellow,
Imperial College London and University of Cape
Town Programme Leader, MRC National Institute for
Medical Research London
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Contributors

• Graeme Meintjes
• Priscilla Mouton
• Keira Skolimowska
• Kerryn van Veen
• Mark Nicol
• Molebogeng Rangaka
• Musaed Abrahams
• Gary Maartens
• Kevin Rebe
• Anne OGarra

• Chelsea Morroni
• Katalin Wilkinson
• Ronnett Seldon
• David Stead
• Dominique Pepper
• Adrian Martineau
• Gilles van Cutsem
• Eric Goemaere
• Steven Lawn

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The Western Cape is the richest part of Africa
but has the worst TB problem in the world
47603
46256
44414
42123
40144
33665
31536
28843
27509
UK
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9
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1
9
9
8
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9
9
9
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0
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2
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2
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Courtesy Dr Keith Cloete, Provincial
administration
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Evolution of HIV prevalence rate in Cape
Metropole(antenatal VCT results)
Courtesy of Dr Keith Cloete, PAWC
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Tuberculosis in Khayelitsha, South Africa
Population 350,000 HIV prevalence 33
3.9 (2005)  TB incidence rate (2006)
1600/100,000 70 TB is HIV associated 5745
cases found in 2006 645 of 3124 reported deaths
in 2006 due to TB (21)
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GF Jooste Referral Area
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GF Jooste Hospital serves a population of 1.2
million 8244 people are prescribed
antiretroviral treatment in catchment area
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An explosion of TB-IRIS
Little information on Cause Diagnosis
Management
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TB-IRIS
1 Spectrum and practical case definition
2 Management with steroids
3 Severe TB-IRIS can complicate drug resistant
tuberculosis
4 Immunology of TB-IRIS
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Nodal enlargement
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New pulmonary infiltrate
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Cold abscess
13
Serous effusions
14
Neurological deterioration
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Design of studies
Excluded or refused consent
Referral to study
Other IRIS manifestations e.g. Bone marrow
infiltration

• Severe
• Resp failure
• Vital structure
• compressed
• 3) TBM

Effusions Pulmonary infiltrate LN Cold abscess
Observational cohort Steroids at discretion of
clinician
Open-label steroids Observational cohort
Non-IRIS Comparison cohort TB-ART
RCT 100 patients
Immunology and genetic studies
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Immunological studies

• Cross-sectional (compare IRIS with non-IRIS
  groups)
• Longitudinal
• within IRIS cohort irrespective of treatment
  allocation (as IRIS progresses) within TB-ART
  cohort to document changes should IRIS occur
• Assays
• Interferon-gamma ELISpot analysis of PBMC using
  various antigens
• 6 and 24 hour restimulation with H37Rv with
  collection of supernatant and harvesting of RNA
  for microarray and qRT-PCR
• 4- and 13- colour FACS (activation status,
  regulatory and Th17 subsets)
•  Serum cytokines
• DNA stored. Consent for genetic testing
  obtained

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PPD specificTh1 expansions
Granuloma expansion
release of inflammatory cytokines
TB-IRIS
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Antigen selection
Acr
38 kDa
ESAT-6
interim analysis of 184 subjects, data censored
27 May 2007
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Cases and controls
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ART gives rise to large expansions of PPD
specific T cells irrespective of whether IRIS
occurs
5000
PPD
4000
3000
IFN-gamma SFC/106 PBMC
2000
1000
0
HIV-TB patient category
21
Responses are directed to several categories of
antigen
ESAT-6
Acr 1
5000
4000
3500
4000
3000
IFN-gamma SFC/106 PBMC
IFN-gamma SFC/106 PBMC
3000
2500
2000
2000
p 0.0003
1500
1000
1000
500
0
0
IRIS
Untreated
TB Rx
IRIS
Untreated
TB Rx
HIV-TB patient category
HIV-TB patient category
38 kDa
H37Rv
4000
3000
p 0.05
3000
2000
IFN-gamma SFC/106 PBMC
IFN-gamma SFC/106 PBMC
2000
1000
1000
0
0
IRIS
TB Rx
IRIS
TB Rx
HIV-TB patient category
HIV-TB patient category
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Longitudinal analysis of TB patients starting ART
n55
Proportion responding to H37Rv
Proportion responding to PPD
90
90
80
80
70
Percentage responders
70
Percentage responders
60
50
60
40
50
30
week 0
week 2
week 4
week 8
week 0
week 2
week 4
week 8
IRIS
Non-IRIS
IRIS
Non-IRIS
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Longitudinal analysis of TB patients starting ART
p 0.01
2500
150
Interferon-? SFC/106 PBMC
150
100
50
0
week 0
At diagnosis
week 0
week 2
IRIS
Non-IRIS
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M. Tuberculosis induced proliferation, activation
and regulation
TB-IRIS n10
80
Day 14 non-IRIS n10
70
60
50
Percentage CD3 cells positive
40
30
20
10
0
CD4CD71
CD4DR
CD8CD71
CD8DR
CD4FoxP3 unstimulated
CD4FoxP3 stimulated
Marker
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Conclusions
IRIS is clinically significant and very
heterogenous. Studies need to be adequately
powered.
ART mediated immune restoration during therapy
of active TB is associated with a substantial
early expansion of TB antigen specific IFN-?
secreting T cells
TB therapy in the absence of ART is also
associated with restoration of responses to some
antigens
An increased response to heat killed bacilli
best associates with IRIS
The numbers of regulatory T cells did not
differ between IRIS and non-IRIS subjects
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Generalisability Protective and pathogenic
immune responses in tuberculosis
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Thank you
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Corticosteroids have little effect on T cell
expansions
3500
3000
2500
2000
IFN gamma SFC/million PBMC
ESAT-6
1500
PPD
1000
500
0
0
10
20
30
40
50
60
70
80
90
Days since onset
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Too much killing of M. tuberculosis?
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Who gets IRIS?
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Why the ELISpot results differ from Bourgarit et
al.
PPD
4000
3000
IFN-gamma SFC/106 PBMC
2000
1000
0
Week 0
Week 2
Week 4
Week 8
IRIS
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When and what form of IRIS?
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Challenges in diagnosisNo diagnostic test
diagnosis of exclusion
Drug resistance 14/141 in Cape Town cohort of
TB-IRIS suspects had MDR or Rifampicin
monoresistance
ALTERNATIVE DIAGNOSIS Bacterial
infections Fungal infection PCP NTM Lymphoma Kapos
is sarcoma
DRUG REACTION especially if hepatic involvement
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MDR-TB-IRIS overlap syndrome Drug resistance and
TB-IRIS

• 14/141 had drug resistance (10)
• 3 known to have MDR
• 2 known to have Rif mono-resistance
• 1 known to have INH mono-resistance
• 6 presented with TB IRIS then MDR diagnosed
• 2 presented with TB IRIS then Rif mono-resistance
  diagnosed
• Most of these patients reported some (or
  complete) improvement on TB Rx and all reported
  symptomatic deterioration after HAART, some
  required steroids
• Fastplaque Rif resistance assay being used to
  expedite diagnosis
• 5 died