Diagnosis of HIV-Associated Tuberculosis Stephen D. Lawn Desmond - - PowerPoint PPT Presentation

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Diagnosis of HIV-Associated Tuberculosis Stephen D. Lawn Desmond Tutu HIV Centre Dept. Of Clinical Research, Faculty of Infectious & Tropical Diseases, Institute of Infectious Disease and London School of Hygiene & Tropical Molecular

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Stephen D. Lawn

Desmond Tutu HIV Centre Institute of Infectious Disease and Molecular Medicine University of Cape Town

  • Dept. Of Clinical Research,

Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK

Diagnosis of HIV-Associated Tuberculosis

NO CONFLICTS OF INTEREST TO DECLARE

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Lawn & Zumla. Lancet 2011

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OUTLINE

  • 1. Defining the need
  • 2. Revisiting the old
  • 3. Ushering in the new
  • 4. Looking to the future
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TB in Cape Town 2009 (n=29,478)

1000 2000 3000 4000 5000 TB notifications Age strata HIV positive HIV unknown HIV negative

Wood and Lawn PLoS ONE 2011

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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0 to 4 (n=2,853) 5 to 9 (n=722) 10 to 14 (n=393) 15 to 19 (n=1,436) 20 to 24 (n=3,184) 25 to 29 (n=4,294) 30 to 34 (n=4,284) 35 to 39 (n=3,762) 40 to 44 (n=2,840) 45 to 49 (n=2,245) 50 to 54 (n=1,479) ≥55 (n=1,986)

Smear + Smear - Culture + No Lab Confirmation Age (years)

Lab Confirmation of TB Diagnoses vs Age

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Prevalence of LTBI by Age

Wood / Lawn IJTLD 2010

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TB / LTBI Spectrum

Young et al. Trends Microbiol 2009 Lawn et al Clin Devel Immunol 2011

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CD4 Count Distribution of Cases of HIV+ TB

500 1,000 1,500 2,000

TB Notifications

CD4 count (cells/µL)

PTB PTB + EPTB EPTB

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HIV-Associated TB Mortality Rate

5 10 15 20 25 30 35 40 45 50

Africa Americas

  • E. Mediterranean

European S.E.Asian

  • W. Pacific

Mortality rate WHO Region

Lawn et al. IJTLD 2009

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So What Do We Need?

500 1,000 1,500 2,000 TB Notifications CD4 count (cells/µL) PTB PTB + EPTB EPTB

1000 2000 3000 4000 5000 TB notifications Age strata HIV positive HIV unknown HIV negative

Rapid detection of resistance to 1st and 2nd line drugs Monitoring response to TB Rx Point-of-care! Low-cost Simple and feasible

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OUTLINE

  • 1. Defining the need
  • 2. Revisiting the old
  • 3. Ushering in the new
  • 4. Looking to the future
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HIV Status, CD4 Count and PTB vs EPTB

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% <50 (n=2,123) 50-99 (n=1,965) 100-149 (n=1,721) 150-199 (n=1,426) 200-349 (n=2,535) 350-499 (n=1,163) ≥500 (n=883) (n=12,507) Percentage of Notifications

CD4 count

PTB PTB + EPTB EPTB

HIV- HIV+

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0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

<50 (n=586) 50-99 (n=456) 100-149 (n=425) 150-199 (n=377) 200-349 (n=711) 350-499 (n=405) >500 (n=269) (n=5,634)

Percentage of Notifications

CD4 (cells / µl)

+ ++ +++ HIV- HIV+

HIV Status, CD4 Cell Count and Sputum Smear-Positive Grade

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HIV Status, CD4 Count and Smear Status

0% 10% 20% 30% 40% 50% 60% 70% 80% <50 (n=1,530) 50-99 (n=1,409) 100-149 (n=1,255) 150-199 (n=1,076) 200-349 (n=1,896) 350-499 (n=882) ≥500 (n=629) (n=9127)

Smear Positivity

CD4 Count

HIV- HIV+

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Increasing diagnostic sensitivity of in the very lowest CD4 cell count strata:

  • Sputum Xpert MTB/RIF
  • Urine LAM
  • Urine Xpert MTB/RIF

Lawn et al. Clin Infect Dis 2012 Lawn et al. JAIDS 2012

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CD4 Count Distribution of Cases of HIV+ TB

500 1,000 1,500 2,000

TB Notifications

CD4 count (cells/µL)

PTB PTB + EPTB EPTB

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OUTLINE

  • 1. Defining the need
  • 2. Revisiting the old
  • 3. Ushering in the new
  • Symptom screening
  • Diagnostic assays
  • 4. Looking to the future
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Symptom Screening

Screen for presence of ≥1 of the following symptoms:

  • 1. Current cough
  • 2. Fever
  • 3. Night sweats
  • 4. Weight loss

Sensitivity: 78.9% Specificity: 49.6% NPV: high if TB prevalence <10%

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All patients Patients with symptoms

WHO screen Any cough Cough >2 weeks 10 20 30 40 50 60 70 80 90 100

Proportion of TB diagnoses (%)

Induced sputum #2 Induced sputum #1 Spot sputum #1

Lawn et al IJTLD 2012; in press

Sensitivity of Symptom Screening for TB Pre-ART

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Culture Antigen detection Electronic ‘noses’ / ‘breathalysers’ Biomarkers Rapid molecular assays

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Microcolony culture techniques: MODS / Thin Layer Agar

– Interim low-cost solution – MODS commercialization – Minion et al. Lancet Infect Dis 2010 – Leung et al. IJTLD 2012 – Feasibility / scale / impact?

Culture

Automated liquid culture and phenotypic DST: gold standard

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Rapid Molecular Diagnostic Assays For TB Diagnosis and DST

Line-Probe Assays

WHO-approved in 2008 Eg Hain Lifesciences MTBDRplus

  • Culture isolates: YES
  • Smear-positive sputum: YES
  • Smear-negative sputum: NO

Technical complexity New ‘GenoQuick MTB’ (Moure et al J Clin Micro 2012)

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XPERT MTB/RIF

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Xpert MTB/RIF: real-time PCR using thermocycling and molecular beacon technology

Lawn & Nicol. Future Microbiology 2011

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Boehme et al NEJM 2010

10 20 30 40 50 60 70 80 90 100 1 2 3

Sensitivity (%)

  • No. sputum samples tested

Smear-positive Smear-negative

Sensitivity of Xpert MTB/RIF Assay (FIND Multi-Country Evaluation)

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Type of TB Sensitivity

Sputum smear-positive

98-100%

Sputum smear-negative

57-83%

Extrapulmonary (range of clinical samples)

25-95%

Lawn & Nicol, Future Microbiology 2011 Lawn & Zumla , Exp Rev Anti-Infect Ther 2012

December 2010

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Xpert and EPTB

Lawn & Zumla , Exp Rev Anti-Infect Ther 2012

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10 20 30 40 50 60 70 <50 50-150 >150 All patients Sensitivity (%) CD4 cell count strata

JAIDS 2012

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10 20 30 40 50 60 70 80 90 100 Sensitivity Specificity Percentage (%) Microscopy Xpert

45% increase in case detection

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Detection of Rifampicin Resistance

  • Problem of false +ves
  • New G4 cartridges

launched Dec 2011

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Xpert MTB/RIF: A ‘game-changer’?

  • Pros include

– Exceptional performance for TB diagnosis – Rapid RIF Resistance screening – Near patient technology

  • Some cons

– RIF resistance specificity – Xpert-negative TB – Expense

  • 4 bay machine $17,000
  • 1 cartridge approx $15

– Simple – but not simple enough – Will it be used at point-of-care?

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AIDS 2012

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  • Xpert-negative TB patients had:
  • very early TB disease
  • less advanced HIV
  • good prognosis

Lawn et al Clin Infect Dis 2012

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Impact of Xpert in South Africa?

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Xpert-NEG (n=25) Xpert-POS (n=64) P value Alive and in- programme 21 (84.0) 54 (84.4) 1.0 Dead 6 (9.4) <0.179 LTFU 4 (16.0) 8 (12.5) 0.733 Transfer-out 1 (1.6) 1.0 Started TB Rx 17 (68) 49 (76.6) 0.4 Time to TB treatment (median [IQR] days) 32 (26-48) 9 (6-18) <0.001

90-day ART Programme Outcomes

Lawn et al Clin Infect Dis 2012

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Lawn et al IJTLD 2012

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Living with HIV, dying of TB We need a POC TB test!

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Urine Antigen Detection

Lipoarabinomannan (LAM)

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10 20 30 40 50 60 70 80 90 100 Microscopy LAM ELISA LAM ELISA + Microscopy

Sensitivty

CD4 >100 CD4 50-100 CD4 <50

Lawn et al. AIDS 2009. Shah et al JAIDS 2009

Specificity 100%

Sensitivity of LAM ELISA for TB Screening Pre-ART

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Determine TB-LAM Ag

Control band Patient sample result Sample pad

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Negative Interm. positive Strong positive

Determine TB-LAM Ag

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Lancet Infectious Diseases 2012

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Agreement between two readers?

Overall agreement 514/516 99.6% (95% CI 98.6-100)

Kappa= 0.97 (95%CI, 0.88-0.99)

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Agreement between TB-ELISA and Determine TB-LAM Strips?

Overall agreement 507/516 98.3% (95%CI, 96.7-99.2) Kappa= 0.84 (95%CI, 0.72-0.92)

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10 20 30 40 50 60 70 80 90 100 Smear LAM Smear + LAM Xpert Xpert + L Diagnostiic sensitivity (%) CD4 >150 CD4 = 50-150 CD4 <50

Sensitivity of LAM POC test

Specificity >98% all strata

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Liquid Culture z Liquid Culture 100% Xpert MTB/RIF 76% Sputum AFB 35%

Sensitivity of TB diagnostics among patients with a CD4 <100 cells/µL

Determine TB-LAM 52%

AFB + LAM = 66%

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LAM-Negative (n=36) LAM-Positive (n=23) P value CD4 count Median (IQR) 115 (69-160) 37 (182-379) 0.01 Hb Median (IQR) 11.6 (10.0-12.5) 8.0 (7.5-9.0) <0.001 Sputum smear- positive (%) 8 (27.2) 10 (43.5) 0.084 Days to culture positivity 17 (14-24) 12 (9-17) 0.005 Mortality (%) 5 (21.7) 0.007

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Liquid culture Sputum Xpert MTB/RIF AFB Sputum Microscopy Determine TB-LAM Deaths

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OUTLINE

  • 1. Defining the need
  • 2. Revisiting the old
  • 3. Ushering in the new
  • 4. Looking to the future
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Culture Antigen detection

Electronic ‘noses’ / ‘breathalysers’

Biomarkers Rapid molecular assays

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LAMP: Loop Mediated Isothermal Amplification

PCR is slow and requires thermocycling LAMP at stable elevated temperature Visual read-out Multiplexing not possible Second prototype: STAG 2012

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‘Fast-Followers’ to Xpert: ......Cheaper and Simpler

Amplification at lower temps Low energy requirements Quick Smart-phone sized hardware Multiple drug resistance mutations

...WATCH THIS SPACE!

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Kolk et al J Clin Micro 2010

Electronic ‘Noses’ / Breathalyzers

  • Electronic detection of

volatile biomarkers using chemical sensors + pattern recognition system

  • Rapid detection of Ag85B

McNerney et al BMC Infect Dis 2010

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The ‘Omics’ Era

  • Transcriptomics
  • Proteomics
  • Metabolomics
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Berry et al Nature 2010 Whole blood 393- transcript signature TB vs LTBI vs healthy controls TB before and after Rx

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CONCLUSIONS

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CONCLUSIONS

  • Huge progress over the past 5 years
  • Major progress in rapid molecular techniques
  • Xpert MTB/RIF

– is a huge step forward – far from the prefect solution – has triggered a huge amount of development

  • Determine TB-LAM

– a POC niche for those with v. low CD4 counts

  • Impact data needed
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So What Have We Got?

500 1,000 1,500 2,000 TB Notifications CD4 count (cells/µL) PTB PTB + EPTB EPTB

1000 2000 3000 4000 5000 TB notifications Age strata HIV positive HIV unknown HIV negative

Rapid detection of resistance to 1st and 2nd line drugs Monitoring response to TB Rx Point-of-care! Low-cost Simple and feasible

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Acknowledgments

  • Cape Town: Robin Wood, Linda-Gail Bekker, Andrew

Kerkhoff, Sophie Brooks, Ankur Gupta, Rishi Gupta, Monica Vogt, Katharina Kranzer, Landon Myer, Matthew McNally, Pearl Pahlana + staff at Hannan Crusaid clinic

  • Mark Nicol, Andrew Whitelaw + NHLS staff
  • Harvard: Jason Andrews, Rochelle Walensky, Ken Freedberg
  • FIND – preferential pricing of cartridges
  • Alere – supplied LAM tests
  • IIDMM, UCT, LSHTM, WT Bloomsbury Centre