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The Lancet Infectious Diseases 11/2012; · 17.39 Impact Factor
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ABSTRACT: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is an early complication of combination antiretroviral therapy (cART). Two forms are recognised: (i) paradoxical - recurrent or new TB symptoms develop after cART initiation in patients receiving TB treatment prior to cART; and (ii) unmasking TB-IRIS - active TB presents within 3 months of cART in patients not receiving TB treatment at cART initiation. The latter has heightened clinical manifestations and a marked inflammatory presentation.
To gain insight into the immune pathogenesis of a case of unmasking TB-IRIS.
The patient was recruited when starting cART and followed up at 4, 12 and 24 weeks of treatment. Peripheral blood mononuclear cells were used for flow cytometry.
Immunological analysis indicated increased CD4+ T-cell proportions from 1.1% at baseline to 14% at 24 weeks (the CD4 count increased from 4 cells/µl at baseline to 41 cells/µl at 24 weeks). HIV viral load fell from 460 774 to 1 405 copies/ml during the same period. The proportion of TB antigen (PPD)-specific CD4+IFN-γ+ cells increased from 0.4% at baseline and 4 weeks (IRIS onset) to 7.8% at 12 weeks (after resolution of the IRIS episode); this fell to 0.7% at 24 weeks. The surface phenotype of CD4+IFN-γ+ cells during the episode was CD45RO+, CD45RA-, CCR7-, CD62L-, CCR5+/- and CD69-. We found a distorted balance between central memory and effector memory T-cells at cART commencement that might have predisposed the patient to unmasking TB-IRIS. We showed that this might have reflected compromised thymic output. Discussion. While it has been suggested that tuberculin-specific Th1-responses induce TB-IRIS in HIV co-infected patients, our data in this case indicated that these cells were expanded only after IRIS onset and were therefore not inducing TB-IRIS.
We describe, in hitherto unpublished detail, the immunological characterisation of an unmasking TB-IRIS case; we show that thymic output may be compromised at IRIS onset.
South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde 06/2012; 102(6):512-7. · 2.04 Impact Factor
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The Lancet 05/2011; 377(9777):1548-50. · 38.28 Impact Factor
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American Journal of Respiratory and Critical Care Medicine 01/2010; 181(1):95. · 11.08 Impact Factor
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Hannah Priyadarshini Gideon,
Katalin Andrea Wilkinson,
Tige R Rustad,
Tolu Oni,
Heinner Guio,
Robert Andrew Kozak,
David R Sherman,
Graeme Meintjes,
Marcel A Behr,
Hans Martin Vordermeier,
Douglas Brownlee Young, Robert John Wilkinson
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ABSTRACT: M. tuberculosis (MTB) species-specific antigenic determinants of the human T cell response are important for immunodiagnosis and vaccination. As hypoxia is a stimulus in chronic tuberculosis infection, we analyzed transcriptional profiles of MTB subject to 168 hours of hypoxia to test the hypothesis that upregulation by hypoxia might result in gene products being recognized as antigens. We identified upregulation of two region of difference (RD) 11 (Rv2658C and Rv2659c), and one RD2 (Rv1986) absent from commonly used BCG strains. In MTB infected persons, the IL-2 ELISpot response to Rv1986 peptides was several times greater than the corresponding IFN-γ response to the reference immunodominant ESAT-6 or CFP-10 antigens. The IL-2 response was confined to two epitopic regions containing residues 61-80 and 161-180. The biggest population of IL-2 secreting T cells was single cytokine positive central memory T cells. The IL-2 response to live MTB bacilli lacking Rv1986 was significantly lower than the response to wild type or mutant complemented with Rv1986. In addition, the IL-2 response to Rv1986 was significantly lower in HIV-TB co-infected persons than in HIV uninfected persons, and significantly increased during antiretroviral therapy. These findings demonstrate that Rv1986 is an immunodominant target of memory T cells and is therefore of relevance when considering the partial efficacy of currently used BCG vaccines and provide evidence for a clinical trial comparing BCG strains.
PLoS Pathogens 01/2010; 6(12):e1001237. · 9.13 Impact Factor
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ABSTRACT: Combination antiretroviral treatment (cART) reduces the risk of tuberculosis in HIV-infected people. Therefore a novel approach to gain insight into protection against tuberculosis is to analyze the T cells that expand in people sensitized by Mycobacterium tuberculosis (MTB) during cART.
To longitudinally analyze CD4 T-cell subsets during the first year of cART, from the time of starting cART (Day 0), in 19 HIV-infected, MTB-sensitized adults.
Peripheral blood mononuclear cells were obtained on Day 0, Weeks 2, 4, 12, 24, 36, and 48 of cART and were stimulated with purified protein derivative (PPD) followed by flow cytometry to analyze surface markers and intracellular cytokines.
CD4(+) T cells significantly increased during follow-up and the viral load fell to undetectable levels in each patient, indicating successful immune restoration. Central memory CD27(+)CD45RA(-) and CD27(+)CCR5(-) CD4(+) cells expanded by 12 weeks (P < 0.02) followed by naive CD27(+)CD45RA(+) cells at 36 weeks (P = 0.02). Terminally differentiated effector CD4(+)CD27(-)CCR7(-) cells decreased by 12 weeks (P = 0.02), paralleled by a proportional decline of PPD-specific CD4(+)IFN-gamma(+) cells (P = 0.02). However, the absolute numbers of PPD-specific IFN-gamma-producing cells, determined by enzyme-linked immunospot assay, increased (P = 0.02).
Rapid effector responses are often measured when evaluating immunity. We show that although cART is associated with an absolute increase in effector function, the proportional response decreased and the strongest correlate of increased cART-mediated immunity in this study was the central memory response.
American Journal of Respiratory and Critical Care Medicine 08/2009; 180(7):674-83. · 11.08 Impact Factor
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American Journal of Respiratory and Critical Care Medicine 06/2009; 179(9):740-2. · 11.08 Impact Factor
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ABSTRACT: Lack of reactivity to the tuberculin skin test (TST) is widely observed in individuals with advanced human immunodeficiency virus type 1 (HIV-1) infection.
Biopsy specimens from the TST reaction site and from skin not infiltrated with purified protein derivative were obtained from 15 HIV-1-infected and 23 uninfected persons who did not have active tuberculosis and who were from a community in which the incidence of tuberculosis was very high. Histologic sections (size, 8 mum) were immunohistochemically stained for CD4, CD8, CD28, CD45RA, CD45RO, CD62L, CD1a, human leukocyte antigen (HLA)-DR, granulysin, interferon-gamma, and FoxP3 and were analyzed by single-cell in situ digital imaging. Peripheral blood mononuclear cells were analyzed using a fluorescence-activated cell sorter.
Biopsy specimens obtained from TST-reactive skin of HIV-1-infected persons demonstrated fewer CD4(+) T cells at the TST site (P = .36) but more HLA-DR(+) T cells (P = .037) than did such biopsy specimens obtained from HIV-1-uninfected persons. Among HIV-1-infected persons, the total number of cells (P = .008) and numbers of CD45RO(+) memory T cells (P = .003) were significantly higher in TST-reactive persons than in TST-unreactive persons. For HIV-1-infected persons, TST induration was inversely correlated with the numbers of FoxP3(+) T cells in the blood (P = .026) but was unrelated to the number of circulating CD4(+) T cells.
For HIV-1 infected persons, the TST depends on memory T cells and is more strongly associated with the numbers of circulating FoxP3(+)CD4(+) T cells than with the total number of CD4(+) T cells.
The Journal of Infectious Diseases 03/2009; 199(5):702-10. · 6.41 Impact Factor
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Graeme Meintjes,
Katalin Andrea Wilkinson,
Molebogeng Xheeda Rangaka,
Keira Skolimowska,
Kerryn van Veen,
Musaed Abrahams,
Ronnett Seldon,
Dominique J Pepper,
Kevin Rebe,
Priscilla Mouton,
Gilles van Cutsem,
Mark Patrick Nicol,
Gary Maartens, Robert John Wilkinson
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ABSTRACT: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) induced by combination antiretroviral therapy (cART) has been attributed to dysregulated expansion of tuberculin PPD-specific IFN-gamma-secreting CD4(+) T cells. Objectives: To investigate the role of type 1 helper T cell expansions and regulatory T cells in HIV-TB IRIS.
Longitudinal and cross-sectional studies of Mycobacterium tuberculosis-specific IFN-gamma enzyme-linked immunospot responses and flow cytometric analysis of blood cells from a total of 129 adults with HIV-1-associated tuberculosis, 98 of whom were prescribed cART.
In cross-sectional analysis the frequency of IFN-gamma-secreting T cells recognizing early secretory antigenic target (ESAT)-6, alpha-crystallins 1 and 2, and PPD of M. tuberculosis was higher in patients with TB-IRIS than in similar patients treated for both HIV-1 and tuberculosis who did not develop IRIS (non-IRIS; P <or= 0.03). The biggest difference was in the recognition of alpha-crystallin molecules: peptide mapping indicated a polyclonal response. Flow cytometric analysis indicated equal proportions of CD4(+) and CD8(+) cells positive for activation markers HLA-DR and CD71 in both patients with TB-IRIS and non-IRIS patients. The percentage of CD4(+) cells positive for FoxP3 (Forkhead box P3) was low in both groups (TB-IRIS, 5.3 +/- 4.5; non-IRIS, 2.46 +/- 2.46; P = 0.13). Eight weeks of longitudinal analysis of patients with tuberculosis who were starting cART showed dynamic changes in antigen-specific IFN-gamma-secreting T cells in both the TB-IRIS and non-IRIS groups: the only significant trend was an increased response to PPD in the TB-IRIS group (P = 0.041).
There is an association between helper T-cell type 1 expansions and TB-IRIS, but the occurrence of similar expansions in non-IRIS brings into question whether these are causal. The defect in immune regulation responsible for TB-IRIS remains to be fully elucidated.
American Journal of Respiratory and Critical Care Medicine 09/2008; 178(10):1083-9. · 11.08 Impact Factor
