Istituto Nazionale per le malattie Infettive L Spallanzani

Istituto Nazionale per le malattie Infettive L. Spallanzani Roma, Italy Immunodiagnosis of TB Delia Goletti Borstel, May 28 th, 2010

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests

Tuberculosis transmission and progression to active disease from latent infection Small PM et al, N Engl J Med, 2001

The challenge of detecting M. tuberculosis infection n Active disease n n Often difficult to isolate: even with good microbiological facilities, the bacillus is recovered in only 60% of cases Latent infection n M. tuberculosis cannot be cultured from latently infected individuals: no gold standard

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests

Tuberculin skin test-1 n Reagent: n n Variability: n n n Purified protein derivative (PPD) commonly shared among different Mycobacteria (M. tuberculosis, BCG and atypical mycobacteria) Reproducibility in giving the test Subjectivity in reading the test Logistics n n Repeat visit needed 3 days before result

Tuberculin skin test (TST)-2 Active TB disease M. tuberculosis Latent TB infection NTM Exposure to environmental mycobacteria BCG-vaccination Positive TST does not distinguish among all these different clinical situations

Tuberculin skin test-3 n False Negatives n skin reaction is a very crude measure: n n Small responses not picked up (real problem in immunosuppressed patients) 10 -25% negative results in active disease (only 75 -90% sensitivity, worse in immunosuppressed)

Need of… n Standardized test (laboratory test) n M. tuberculosis-specific reagents n Possibility to discriminate between the different stages of tuberculosis

Need of… n Standardized test (laboratory test) n M. tuberculosis-specific reagents n Possibility to discriminate between the different stages of tuberculosis

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests

Quanti. FERON®-TB n Nil n Tuberculin PPD n M. Avium PPD n Mitogen

Quanti. FERON®-TB Test Method (in 2002. . . ) Stage 1: Whole Blood Culture Nil Avian Tuberculin Mitogen Control PPD Control n. Heparinised whole blood n. Transfer undiluted whole blood into wells of a culture plate and add antigens n. Culture n. TB overnight at 37 o. C infected individuals respond by secreting IFN-g Stage 2: IFN-g ELISA n. COLOR n. OD n. TMB n. Harvest Plasma from above settled cells and incubate 60 min in ‘Sandwich’ ELISA n. Wash, add Substrate, 30 min nthen stop reaction nincubate Curve 450 nm n. Standard n. IFN-g IU/ml n. Measure ndetermine OD and IFN-g levels

Quanti. FERON®-TB Test Result Nil Tuberculin PPD M. avium Mitogen Indeterminate – – Negative – – – +++ M. tuberculosis, atypical mycobacteria infection different from M. avium – +++ + +++ M. Avium infection – + +++ PPD and BCG vaccination 16

Need of… n Standardized test (laboratory test) n M. tuberculosis-specific reagents n Possibility to discriminate between the different stages of tuberculosis

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests

Species specificities of ESAT-6 and CFP-10 Tuberculosis complex M tuberculosis M africanum M bovis BCG substrain gothenburg moreau tice tokyo danish glaxo montreal pasteur Antigens ESAT CFP + + + - - Environmental strains Antigens ESAT CFP M abcessus M avium M branderi M celatum M chelonae M fortuitum M gordonii M intracellulare M kansasii M malmoense M marinum M oenavense M scrofulaceum M smegmatis M szulgai M terrae M vaccae M xenopi + + + -

Agenda n Problems in the diagnosis of TB n TST n Quanti. FERON-TB n RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests

T-SPOT TB ESAT-6: 17 peptides CFP-10: 18 peptides Lalvani et al, JID 2001

How the T-SPOT TB technology works Collect white cells using BD CPT tube or Ficoll extraction. Add white cells and TB antigens to wells. T cells release interferon-g. Interferon-g captured by antibodies. Incubate, wash and add conjugated second antibody to interferon-g. Add substrate and coun. T-SPOTs by eye or use reader. Each spot is an individual T cell that has released interferon-g.

T-SPOT TB

T-SPOT TB n T-SPOT TB™ is a patented method to detect pathogen-specific T cells. n n n A simplified variant of the ex vivo elispot method developed by Dr. Ajit Lalvani Complete system - kit + instrumentation Validated and produced to international quality standards (ISO 13485: 2003, GMP) n Standardized n Quality-controlled n CE marked for in vitro diagnostic use

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests

Quanti. FERON®-TB Gold In tube: peptides used CFP-10: 6 peptides ESAT-6: 7 peptides Mori et al, AJRCCM 2004 TB 7. 7: 1 peptide

Quanti. FERON®-TB Gold In tube: methods Collect peripheral venous blood (4 or 8 ml) Incubate overnight at 37˚C Keep the plasma harvested at: - 4 C for 15 days - 20 C for 2 months ELISA Centrifuge for 5 minutes Harvest plasma SOFTWARE for DATA ANALYSIS

Quanti. FERON®-TB Gold In tube Stage 1: Culture overnight at 37 o. C M. tuberculosis-infected individuals respond by secreting IFN-g Stage 2: IFN-g ELISA TMB Harvest Plasma from above settled cells and incubate 120 min in ‘Sandwich’ ELISA Wash, add Substrate, incubate 30 min then stop reaction Standard Curve OD 450 nm COLOR IFN-g IU/ml Measure OD and determine IFN-g levels

Comparison TST vs IGRA TST RD 1 IGRA ELISPOT (e. g. ELISA (e. g. T-SPOT TB) Quanti. FERON-TB Gold IT) Antigens PPD Peptides from CFP-10, ESAT-6 and TB 7. 7 Tests’ substrate Skin PBMC Whole Blood Time required for the results 72 h 24 h Cells involved Cytokines involved Neutrophils, CD 4, CD 8 that transmigrate out of capillaries into the skin. Treg (CD 4+CD 25 high. Fox. P 3+). IFN-g, TNF-a, TNF-b CD 4 T cells in vitro IFN-g Modified from Mack et al, ERJ 2009

Comparison TST vs IGRA TST RD 1 IGRA ELISPOT (e. g. ELISA (e. g. T-SPOT TB) Quanti. FERON-TB Gold IT) Read-out Measure of diameter of dermal induration Enumeration of IFN-g spots Measure of optical density values of IFN-g production Outcomes measure Level of induration Number of IFN-g producing T cells Plasma concentration of IFN-g produced by T cells Read-out units mm IFN-g spot forming cells IU/ml Modified from Mack et al, ERJ 2009

Comparison TST vs IGRA TST RD 1 IGRA ELISPOT (e. g. ELISA (e. g. Quanti. FERON-TB Gold IT) T-SPOT TB) Internal control no yes Technical expertise required Medium high Low medium Cost of reader machine - Medium high Low medium Cost of the assay 2 -3 euros 30 -35 euros? Modified from Mack et al, ERJ 2009

Accuracy n TST n T-SPOT TB n Quanti. FERON-TB Gold

TST sensitivity SENSITIVITY TST 77% Pai et al, Annals 2008

TST specificity SPECIFICITY TST 97% SPECIFICITY TST 59% in those BCG-vaccinated Pai et al, Annals 2008

Sensitivity T-SPOT TB vs Quanti. FERON TBGold In tube SENSITIVITY T SPOT TB 90% SENSITIVITY QFT-IT 70% Pai et al, Annals 2008

Specificity T-SPOT TB vs Quanti. FERON TBGold In tube SPECIFICITY T SPOT TB 93% SPECIFICITY QFT-IT 96% Pai et al, Annals 2008

RD 1 -IGRA Active TB disease Positive RD 1 -IGRA tuberculosis M. infection/disease Latent TB infection NTM BCG-vaccination Positive RD 1 -IGRA do not distinguish active TB disease and LTBI

Vulnerable populations n Children n Immuno-suppressed for: n n HIV Autoimmune disease

Comparison of TST/IGRAs in children with active TB Source Patient number TST+ T-SPOT TB+ QTF-G+ To note % % % Liebeschuetz et al, Lancet 2004 57 57 81 NA TB microbiologically diagnosed Kampmann et al, ERJ 2009 25 83 58 80 TB microbiologically diagnosed Hermann JL et al, Plos 2008 32 87 NA 78 TB microbiologically diagnosed in 48% Nicol et al, Pediatrics 2009 10 80 50 NA TB microbiologically diagnosed Connell et al, Plos 2008 9 89 100 89 TB clinically diagnosed

Comparison of TST/IGRAs in patients HIV+ with active TB microbiologically confirmed Source Patient number TST+ T-SPOT TB+ QTF-G+ % % % RD 1 proteins ELISPOT+ % To note Liebeschuetz et al, Lancet 2004 57 35 81 nd nd T cell anergy no reported, CD 4 nd Vincenti et al, Clin Exp Imm 2007 13 46 85 85 nd T cell anergy in 20%, CD 4 median 179 Raby et al, Plos ONE 2008 59 55 nd 75 nd T cell anergy in 17%, CD 4 median 212 Aabye et al, Plos ONE 2009 68 nd nd 83 nd T cell anergy in 22%, CD 4 median 179 Rangaka et al, CID 2007 31 67 nd nd 90 T cell anergy no reported, No commercial test, CD 4 median 167

Comparison of TST/IGRAs in patients with active TB microbiologically confirmed Source Patient number TST+ T-SPOT TB+ QTF-G+ % % % RD 1 proteins ELISPOT+ % Liebeschuetz et al, Lancet 2004 57 35 81 nd nd T cell anergy no reported, CD 4 nd Vincenti et al, Clin Exp Imm 2007 13 46 85 85 nd 69 69 T cell anergy in 20%, CD 4 median 179 Raby et al, Plos ONE 2008 59 nd 75 nd T cell anergy in 17%, CD 4 median 212 Aabye et al, Plos ONE 2009 68 nd T cell anergy in 14%, CD 4 median 179 Rangaka et al, CID 2007 31 90 T cell anergy no reported, No commercial test, CD 4 median 167 55 63 nd nd 83 65 67 nd nd To note

Proportion of in vitro anergic responses to IGRAs in HIV+ patients Brock, Resp Res 2007 Vincenti, Clin Exp Imm 2007 Luetkem eyer, AJRCCM 2007 Clark, Clin Exp Imm 2007 Test QFT ELISPOT QFT N. Paz 590 111 196 201 247 84 4 (24%) 12 (57%) 5 (16%) 4 (6%) 6 (16%) 6 (46%) 100 -200 1 (3%) 4 (19%) 4 (3. 6%) 12 (31%) 3 (15%) 201 -300 5 (8%) 3 (14%) 10 (26) 3 (13%) 10 (2%) 2 (10%) 8 (21%) 4 (8%) CD 4 home-made Karam, Rabi, Plos ONE 2008 home-made per ml <100 >300 1 (NA) 6 (3. 9%)

Immunocompromised for immune suppressive therapy due to autoimmune diseases Bartalesi et al, ERJ 2009

Predictive value of IGRA: HIV-negative subjects Diel et al, AJRCCM 2009

Predictive value of IGRA: HIV+ subjects Aichelbuurg et al, CID 2009

Predictive value of IGRA: HIV-negative subjects Kik et al, ERJ 2009

Need of… n Standardized test (laboratory test) n M. tuberculosis-specific reagents n Possibility to discriminate between the different stages of tuberculosis

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests n n n IGRA based on RD 1 selected peptides or on antigens of latency IP-10 detection IGRA at the site of TB disease

Why is it important to distinguish between latent infection and active TB disease? n To provide a correct diagnosis: n Active TB disease: n n Latent infection To provide a correct and efficacious therapy: n n n Organ destruction and/or death Spread of infection in the community Active TB disease: 2 months therapy with 4 drugs and the 2 months therapy with 2 drugs Latent TB infection: 6 months therapy with one drug To save human and economic costs avoiding complex evaluations (i. e. clinical, radiological and surgery procedures). Ex: extra-pulmonary TB

Our approach: use of peptides from ESAT-6 and CFP-10 selected by computational analysis Peptide Position sequence DR-serological specificities covered 1 - ESAT-6 6 -28 1, 3, 4, 8, 11(5), 13(6), 52, 53 2 - ESAT-6 66 -78 3, 8, 11(5), 13(6), 15(2), 52 3 - CFP-10 18 -31 3, 5, 11(5), 52 4 - CFP-10 43 -70 1, 3, 4, 7, 8, 11(5), 13(6), 15(2), 52 5 - CFP-10 74 -86 3, 4, 7, 11(5), 12(5), 13(6), 15 (2) Peptides selected by computational analysis that cover more than 90% of the HLA class II specificities

IFN-g response to RD 1 selected peptides is associated to active TB Vincenti et al, Mol Med 2003

In patients with active TB the response to RD 1 selected peptides decreases after efficacious treatment Carrara et al, CID 2004

Sensitivity, specificity and diagnostic odds ratio of the different assays for the immune diagnosis of TB Assay RD 1 ELISPOT assays Sensitivity Specificity % % Selected peptides 70 91 22 Intact proteins 83 56 6 91 59 15 83 59 7 RD 1 commercially T-SPOT TB available assays QFT Gold Diagnostic odds ratio Goletti et al, CMI 2006

TBNET report Goletti et al, PLo. S ONE 2008

In vitro IFN-g response to Rv 2628 antigen of latency is associated with remote LTBI Goletti et al, ERJ 2010

LTBI vs Active TB: HBHA Berlin, October 4 th, 2008 From Hougardy et al, 2007

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests n n n IGRA based on RD 1 selected peptides or on antigens of latency IGRA at the site of TB disease IP-10 detection

IGRA at the site of TB disease: BAL vs blood From Jafari, AJRCCM 2009

IGRA at the site of TB disease: Pleural fluid vs blood PBMC Berlin, October 4 th, 2008 PLEURAL CELLS From Losi et al, ERJ 2007

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests n n n IGRA based on RD 1 selected peptides or on antigens of latency IGRA at the site of TB disease IP-10 detection

IP-10 is induced by ESAT-6, CFP 10 e TB 7. 7 in whole blood from patients with TB disease QFT-Gold, detection of: IP-10 (Ruwald, 2007): n n Significant higher in patients with active disease IP-10 detectable in patients with active TB scored negative by IFN-g detection of the QFT-Gold

Detection of IP-10 in the plasma harvested from Quanti. FERON-TB Gold In-tube From Ruwald et al, modified Microbes Infection 2007

IP-10 and MCP-2 in the plasma harvested from Quanti. FERON-TB Gold In-tube are associated with active TB From Ruwald et al, ERJ 2008

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests n n n IGRA based on RD 1 selected peptides or on antigens of latency IGRA at the site of TB disease IP-10 detection

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests n n n IGRA based on RD 1 selected peptides or on antigens of latency IP-10 detection IGRA at the site of TB disease

Dynamic relationship between IFN-g and IL-2 profile of tuberculosis-specific T cells and antigen load M. From Millington, J Immunol 2007, modified

Agenda n Problems in the diagnosis of TB n TST n IGRA n n Quanti. FERON-TB RD 1 -based assays: n n n T-SPOT TB Quanti. FERON-TB Gold New experimental tests n n n IGRA based on RD 1 selected peptides or on antigens of latency IP-10 detection IGRA at the site of TB disease

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