Mycobacterial immune reconstitution inflammatory syndrome in HIV-1 infection after antiretroviral therapy is associated with deregulated specific T-cell responses: beneficial effect of IL-2 and GM-CSF immunotherapy

Complexity of Mycobacterium avium complex immune reconstitution inflammatory syndrome (MAC-IRIS) in a patient with HIV

We report a case of Mycobacterium avium complex immune reconstitution inflammatory syndrome (MAC-IRIS) in a patient with HIV positive. Initial presentation was that of a purpuric purple macular rash in-keeping with Kaposi sarcoma as an AIDS defining illness. Three weeks following the initiation of antiretroviral treatment (ART) she developed chest pain, dry cough and fever. A diagnosis of MAC was made through imaging and sputum cultures and appropriate treatment was initiated. Despite adequate management with evidence of good immunological and virological response, the patient represented with persistent symptoms. Repeat CT of the chest confirmed worsening lymphadenopathy with necrosis. Given these findings, a diagnosis of MAC-IRIS was made with resolution of fever after corticosteroids were initiated. This case highlights the importance of considering MAC as a cause of IRIS in severely immunosuppressed patients with HIV.

Severe cryptococcal-associated neurological immune reconstitution inflammatory syndrome in a renal transplant recipient treated with adalimumab

Cryptococcosis is a major concern in organ transplant recipients. A decrease in immunosuppressants following the initiation of antifungal therapy is currently recommended, but can occasionally be complicated by the onset of immune reconstitution inflammatory syndrome (IRIS). We report on a case of cryptococcosis in a kidney transplant recipient, compounded by severe neurological IRIS, the outcome of which was unfavorable despite the use of anti-tumor necrosis factor-alpha monoclonal antibodies.

Multifarious immunotherapeutic approaches to cure HIV-1 infection

Immunotherapy in the context of treated HIV-1 infection aims to improve immune responses to achieve better control of the virus. To date, multifaceted immunotherapeutic approaches have been shown to reduce immune activation and increase CD4 T-lymphocyte counts, further to the effects of antiretroviral therapy alone, in addition to improving HIV-1-specific T-cell responses. While sterilizing cure of HIV-1 would involve elimination of all replication-competent virus, a functional cure in which the host has long-lasting control of viral replication may be more feasible. In this commentary, we discuss novel strategies aimed at targeting the latent viral reservoir with cure of HIV-1 infection being the ultimate goal, an achievement that would have considerable impact on worldwide HIV-1 infection.

Therapeutic immunisation plus cytokine and hormone therapy improves CD4 T-cell counts, restores anti-HIV-1 responses and reduces immune activation in treated chronic HIV-1 infection

BACKGROUND

This randomised, open label, phase I, immunotherapeutic study investigated the effects of interleukin (IL)-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), recombinant human growth hormone (rhGH), and therapeutic immunisation (a Clade B DNA vaccine) on combination antiretroviral therapy (cART)-treated HIV-1-infected individuals, with the objective to reverse residual T-cell dysfunction.

METHODS

Twelve HIV-1(+) patients on suppressive cART with baseline CD4 T-cell counts >400 cells/mm(3) blood were randomised into one of three groups: (1) vaccine, IL-2, GM-CSF and rhGH (n=3); (2) vaccine alone (n=4); or (3) IL-2, GM-CSF and rhGH (n=5). Samples were collected at weeks 0, 1, 2, 4, 6, 8, 12, 16, 24 and 48. Interferon (IFN)-γ, IL-2, IL-4 and perforin ELISpot assays performed at each time point quantified functional responses to Gag p17/p24, Nef, Rev, and Tat peptides; and detailed T-cell immunophenotyping was undertaken by flow cytometry. Proviral DNA was also measured.

RESULTS

Median baseline CD4 T-cell count was 757 cells/mm(3) (interquartile range [IQR] 567-886 cells/mm(3)), median age 48 years (IQR 42-51 years), and plasma HIV-1-RNA <50 copies/ml for all subjects. Patients who received vaccine plus IL-2, GM-CSF and rhGH (group 1) showed the most marked changes. Assessing mean changes from baseline to week 48 revealed significantly elevated numbers of CD4 T cells (p=0.0083) and improved CD4/CD8 T-cell ratios (p=0.0033). This was accompanied by a significant reduction in expression of CD38 on CD4 T cells (p=0.0194), significantly increased IFN-γ and IL-2 production in response to Gag (p=0.0122) and elevated IFN-γ production in response to Tat (p=0.041) at week 48 compared to baseline. Subjects in all treatment groups showed significantly reduced PD-1 expression at week 48 compared to baseline, with some reductions in proviral DNA.

CONCLUSIONS

Multifarious immunotherapeutic approaches in the context of fully suppressive cART further reduce immune activation, and improve both CD4 T-lymphocyte counts and HIV-1-specific T-cell responses (NCT01130376).

The immune reconstitution inflammatory syndrome: a clinical update

The immune reconstitution inflammatory syndrome (IRIS) is a well-described phenomenon in HIV-infected patients following initiation of antiretroviral therapy and can lead to significant morbidity and mortality in some patients. Risk for IRIS is enhanced in those with low CD4 counts and preexisting opportunistic infections. The development of pathogen-specific definitions of IRIS has aided classification of patients and has facilitated research. Newer data on optimal timing of ART initiation, with additional data in the setting of tuberculosis and cryptococcal meningitis, will help guide strategies to decrease the risk of IRIS but must balance the risks of HIV disease progression. Managing patients with IRIS can be challenging. Treatment options include pathogen-specific therapy, antiinflammatory therapies, and other novel approaches.

Circulating inflammatory biomarkers can predict and characterize tuberculosis-associated immune reconstitution inflammatory syndrome

OBJECTIVE

To identify inflammatory biomarker profiles during paradoxical and unmasking tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS), and determine whether differences in biomarkers prior to antiretroviral therapy (ART) predict subsequent development of TB-IRIS.

DESIGN

Case-control study within a cohort of patients initiating ART in South Africa (n = 498).

METHODS

Participants were followed up for 24 weeks for development of TB-IRIS. Plasma samples were collected at baseline and presentation with symptoms. Groups of cases and controls were as follows: pre-ART TB and developed paradoxical TB-IRIS (n = 9); pre-ART TB but no IRIS (n = 12); no pre-ART TB but developed unmasking TB-IRIS (n = 13); no pre-ART TB and no TB or IRIS during treatment (n = 12). Concentrations of 18 cytokines and chemokines, and C-reactive protein (CRP), were measured and compared.

RESULTS

Event samples were drawn a median of 28 days after ART initiation [interquartile range (IQR) 14-56 days]. During paradoxical TB-IRIS events, there were lower median concentrations of interleukin-10 [IL-10; 22.1 (IQR 15.3-34.9) vs. 82.2 (29.4-128.4) pg/ml, P = 0.047] and monocyte chemotactic protein-1 [MCP-1; 27.6 (20.0-29.7) vs. 71.4 (40.6-77.8) pg/ml, P = 0.005], and higher CRP: IL-10 ratio [2.2 × 10³ (1.8-3.4) vs. 0.3 × 10³ (0.2-0.5), P = 0.003] than in controls. Patients who developed unmasking TB-IRIS had higher median pre-ART levels of CRP [25 (8-47) vs. 6 (lower limit of detection, LLD-12) mg/l, P = 0.046] and interferon gamma (IFN-γ) [9.1 (4.4-24.7) vs. 0.9 (LLD-8.7) pg/ml, P = 0.032] than controls.

CONCLUSION

Patients with unmasking TB-IRIS had higher pre-ART levels of plasma IFN-γ and CRP, consistent with preexisting subclinical TB. Paradoxical TB-IRIS was associated with lower levels of biomarkers of monocyte and regulatory T-cell activity, and higher CRP.

Management of patients with the immune reconstitution inflammatory syndrome

A significant proportion of patients present with the immune reconstitution inflammatory syndrome (IRIS) after commencing antiretroviral therapy (ART). This syndrome is most frequently associated with infective causes. The lack of evidence-based treatment guidelines poses challenges in the management of these patients. Alternative causes for deterioration should be excluded, and optimization of treatment for the underlying opportunistic infection is essential. In addition, anti-inflammatory or immunomodulatory therapy may be considered, particularly in severe cases. Corticosteroids, the only treatment for which clinical trial data exist (for treating paradoxical tuberculosis-associated IRIS), are the treatment most frequently used in IRIS. Limited anecdotal reports of benefit exist for other agents, including NSAIDs, pentoxifylline, montelukast, thalidomide, and hydroxychloroquine. Therapeutic procedures (eg, aspiration of pus collections) play an important role in some patients. Interruption of ART may be considered in life-threatening forms of IRIS.

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

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/microL and 17 healthy controls. Leukocytes producing interferon-gamma (IFNgamma) 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-DR(hi)) and regulatory (CD25 CD127(lo) 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 IFNgamma 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 IFNgamma 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 IFNgamma responses and reactive plasma IgG. IRD does not reflect a paucity of regulatory CD4 T-cells.

Biomarkers of HIV Immune Reconstitution Inflammatory Syndrome

Dysregulation of the immune system drives HIV pathogenesis. As we develop new ways to treat HIV and AIDS, we encounter new clinical ramifications of our treatment on regulatory components of the immune system. HIV-associated Immune Reconstitution Inflammatory Syndrome (IRIS) occurs after initiation of anti-retroviral therapy (ART) with inappropriate and dysbalanced restoration of the immune system resulting in pathologic inflammatory reactions with significant morbidity. IRIS is most commonly associated with latent, occult, or past infections, including tuberculosis, Cryptococcus neoformans, and Mycobacterium avium-complex. We discuss common clinical presentations, new diagnostic modalities, current hypotheses of IRIS pathogenesis, and future directions of IRIS-related research, focusing on the identification of biomarkers that can be used to predict and diagnose IRIS.

Combined use of cytokines, hormones and therapeutic vaccines during effective antiretroviral therapy

Immune-based therapies using vaccines, cytokines and hormones are being considered in the context of effective antiretroviral therapy to induce immunologically defined long-term nonprogressor status in chronically infected HIV-1 patients. Such immunotherapy must allow induction or regeneration of anti-HIV-1 immune responses with the potential to control viremia, activate and eradicate viral reservoirs, and alleviate the immunosuppression caused by HIV-1, eventually possibly reaching the status of a virologically defined ‘elite controller’ with an absence of detectable viremia and no progression to disease over a long period of time. This article summarizes pilot studies utilizing therapeutic vaccines, cytokines and/or hormones in treated HIV-1 infection, and focuses on novel agents and immunotherapeutic options that may have the potential to augment or replace existing antiretroviral therapy with the aim of inducing nonprogressor status in the infected host.

Immune reconstitution inflammatory syndrome in HIV

PURPOSE OF REVIEW

The purpose of this review is to describe the epidemiology, clinical features, putative immune mechanisms and management of immune reconstitution inflammatory syndrome (IRIS) using data published in the last 2 years.

RECENT FINDINGS

Ever more conditions are reported as IRIS events. These most frequently occur with mycobacterial (tuberculosis or Mycobacterium avium complex infection) or cryptococcal disease (each in approximately 30% of cases). Definitions have been proposed for its clinical diagnosis. These suffer from a lack of prospective studies to support their predictive value. The immunopathogenesis of IRIS appears to be related to the interaction between HAART-induced changes in host immune response and the presence of (usually microbial) antigen. Increasing evidence exists that this might be an anatomically compartmentalized phenomenon, such that immune responses may be localized to specific tissue sites such as the brain. This has implications for the use of simple blood tests, such as CD4 count or change in viral load, when assessing risk of IRIS. Treatment options include immune modulation, though supportive care is typically all that is required, unless symptoms are prolonged, significant or life-threatening.

SUMMARY

IRIS is common and will become more so as HAART is rolled out worldwide. Clear clinical definitions are required to avoid its over-diagnosis due to misclassification of other conditions.