Immunological profiles of immune restoration disease presenting as mycobacterial lymphadenitis and cryptococcal meningitis

Department of Clinical Immunology and Immunogenetics, Royal Perth Hospital, Australia
HIV Medicine (Impact Factor: 3.45). 04/2008; 9(5):307 - 316. DOI: 10.1111/j.1468-1293.2008.00565.x
Source: PubMed

ABSTRACT Objectives A proportion of HIV patients beginning antiretroviral therapy (ART) develop immune restoration disease (IRD). Immunological characteristics of IRD were investigated in a cohort of HIV patients beginning therapy in Kuala Lumpur, Malaysia.Methods Peripheral blood mononuclear cells were collected at weeks 0, 6, 12, 24 and 48 of ART from five patients experiencing IRD [two with cryptococcal and three with Mycobacterium tuberculosis (Mtb) disease], eight non-IRD controls who had begun ART with CD4 T-cell counts of <100 cells/μL and 17 healthy controls. Leukocytes producing interferon-gamma (IFNγ) were quantified by enzyme-linked immunospot assay after stimulation with purified protein derivative (PPD), early secretory antigenic target-6 (ESAT-6), Cryptococcus neoformans or Cytomegalovirus antigens. Plasma immunoglobulin (IgG) antibodies reactive with these antigens were assessed by enzyme-linked immunosorbent assay. Proportions of activated (HLA-DRhi) and regulatory (CD25 CD127lo and CTLA-4+) CD4 T-cells were quantified by flow cytometry.Results Plasma HIV RNA declined and CD4 T-cell counts rose within 8–27 weeks on ART. Mtb IRD patients displayed elevated IFNγ responses and/or plasma IgG to PPD, but none responded to ESAT-6. Cryptococcal IRD occurred in patients with low baseline CD4 T-cell counts and involved clear IFNγ and antibody responses to cryptococcal antigen. Proportions of activated and regulatory CD4 T-cells declined on ART, but remained higher in patients than in healthy controls. At the time of IRD, proportions of activated CD4 T-cells and regulatory CD4 T-cells were generally elevated relative to other patients.Conclusions Cryptococcal and Mtb IRD generally coincide with peaks in the proportion of activated T-cells, pathogen-specific IFNγ responses and reactive plasma IgG. IRD does not reflect a paucity of regulatory CD4 T-cells.

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    ABSTRACT: Background Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) remains a poorly understood complication in HIV-TB patients receiving antiretroviral therapy (ART). TB-IRIS could be associated with an exaggerated immune response to TB-antigens. We compared the recovery of IFNγ responses to recall and TB-antigens and explored in vitro innate cytokine production in TB-IRIS patients. Methods In a prospective cohort study of HIV-TB co-infected patients treated for TB before ART initiation, we compared 18 patients who developed TB-IRIS with 18 non-IRIS controls matched for age, sex and CD4 count. We analyzed IFNγ ELISpot responses to CMV, influenza, TB and LPS before ART and during TB-IRIS. CMV and LPS stimulated ELISpot supernatants were subsequently evaluated for production of IL-12p70, IL-6, TNFα and IL-10 by Luminex. ResultsBefore ART, all responses were similar between TB-IRIS patients and non-IRIS controls. During TB-IRIS, IFNγ responses to TB and influenza antigens were comparable between TB-IRIS patients and non-IRIS controls, but responses to CMV and LPS remained significantly lower in TB-IRIS patients. Production of innate cytokines was similar between TB-IRIS patients and non-IRIS controls. However, upon LPS stimulation, IL-6/IL-10 and TNFα/IL-10 ratios were increased in TB-IRIS patients compared to non-IRIS controls. ConclusionTB-IRIS patients did not display excessive IFNγ responses to TB-antigens. In contrast, the reconstitution of CMV and LPS responses was delayed in the TB-IRIS group. For LPS, this was linked with a pro-inflammatory shift in the innate cytokine balance. These data are in support of a prominent role of the innate immune system in TB-IRIS.
    PLoS ONE 11/2014; 9(11):e113101. DOI:10.1371/journal.pone.0113101 · 3.53 Impact Factor
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    ABSTRACT: Background: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a substantial problem in HIV/TB coinfected patients commencing antiretroviral therapy (ART). The immunopathogenesis of TB-IRIS includes increased production of proinflammatory chemokines and cytokines, including interleukin-18, which is a signature cytokine of the nucleotide-binding domain and leucine-rich repeat pyrin containing protein-3 inflammasome. We compared plasma levels of interleukin-18 and other biomarkers of monocyte/macrophage activation in the prediction and characterization of TB-IRIS. Methods: Biomarkers were assayed pre-ART and during TB-IRIS, or equivalent timepoint, in a case–control study of Malaysian HIV patients with paradoxical or unmasking TB-IRIS (n¼15), TB no IRIS (n¼14), and no TB or IRIS (n¼15). Findings for interleukin-18 were verified in another cohort of patients with paradoxical TB-IRIS (n¼26) and their controls (n¼22) from India. Results: Interleukin-18 was higher in TB-IRIS patients pre-ART and during the event in both Malaysian patients (P<0.0001) and Indian patients (P<0.01). CXCL10 was higher pre-ART (P<0.001), mainly in paradoxical TB-IRIS patients, and during TB-IRIS (P<0.001), whereas CXCL8 was only higher during TB-IRIS (P<0.001). Soluble(s) CD14 was increased in all patients with HIV/TB coinfection pre-ART and during TB-IRIS or equivalent time-point, compared with patients without TB. In contrast, interferon-g was lower before and during TB-IRIS. By receiver operating curve analysis, CXCL10, and/or interleukin-18 pre-ART were predictive of TB-IRIS. Conclusion: Plasma interleukin-18 levels pre-ART are candidate biomarkers for predicting paradoxical and unmasking TB-IRIS and should be investigated for risk stratification and elucidation of disease pathogenesis.
    AIDS 02/2015; 29. DOI:10.1097/QAD.0000000000000557 · 6.56 Impact Factor
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    ABSTRACT: Access to antiretroviral therapy (ART) is improving worldwide. Immune reconstitution inflammatory syndrome (IRIS) is a common complication of ART initiation. In this review, we provide an overview of clinical and epidemiological features of HIV-associated IRIS, current understanding of pathophysiological mechanisms, available therapy, and preventive strategies. The spectrum of HIV-associated IRIS is described, with a particular focus on three important pathogen-associated forms: tuberculosis-associated IRIS, cryptococcal IRIS, and Kaposi's sarcoma IRIS. While the clinical features and epidemiology are well described, there are major gaps in our understanding of pathophysiology and as a result therapeutic and preventative strategies are suboptimal. Timing of ART initiation is critical to reduce IRIS-associated morbidity. Improved understanding of the pathophysiology of IRIS will hopefully enable improved diagnostic modalities and better targeted treatments to be developed.


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May 30, 2014