Management of patients with the immune reconstitution inflammatory syndrome

Drug allergy and non-HIV immune reconstitution inflammatory syndrome

Non-HIV immune reconstitution inflammatory syndrome (non-HIV IRIS) is associated with the recovery from an immunocompromised condition. It is defined as inflammatory disorders caused by antigens, including drugs or pathogenic microorganisms present prior to immune recovery, or by the exacerbation of an inflammatory disorder that was already present. Drug-induced hypersensitivity syndrome is a prototype of IRIS, and the pathophysiology of non-HIV IRIS can be recognized in several disorders treated with corticosteroids, immunosuppressants, molecular-targeted drugs, TNF-α antibody drugs, immune checkpoint inhibitors, and dipeptidyl peptidase-4 inhibitors. This review focuses on the relationship between the immune mechanism of non-HIV IRIS and drug allergies, especially severe drug eruption. The antigen recognition mechanism in drug allergy varies depending on the clinical type and the causative drug. The p-i concept is the main mechanism in severe drug eruption such as Stevens-Johnson syndrome/toxic epidermal necrolysis, and drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Lymphocytes activated by an antigen other than a drug, such as a virus, can also develop drug allergy by the loose binding of drugs with immune receptors of T cells or human leukocyte antigen. Therefore, fluctuations in the immune environment affect the onset of severe drug eruption. Novel agents that cause major changes in immunity have been marketed mainly for autoimmune diseases and malignant tumors; therefore, it is necessary to consider their effects when treating severe drug eruptions. Moreover, although a list of diagnostic criteria for this syndrome has been drafted, predictive and diagnostic biomarkers for this syndrome needs to be urgently developed.

Tuberculosis IRIS: Pathogenesis, Presentation, and Management across the Spectrum of Disease

Antiretroviral therapy (ART), while essential in combatting tuberculosis (TB) and HIV coinfection, is often complicated by the TB-associated immune reconstitution inflammatory syndrome (TB-IRIS). Depending on the TB disease site and treatment status at ART initiation, this immune-mediated worsening of TB pathology can take the form of paradoxical TB-IRIS, unmasking TB-IRIS, or CNS TB-IRIS. Each form of TB-IRIS has unique implications for diagnosis and treatment. Recently published studies have emphasized the importance of neutrophils and T cell subtypes in TB-IRIS pathogenesis, alongside the recognized role of CD4 T cells and macrophages. Research has also refined our prognostic understanding, revealing how the disease can impact lung function. While corticosteroids remain the only trial-supported therapy for prevention and management of TB-IRIS, increasing interest has been given to biologic therapies directly targeting the immune pathology. TB-IRIS, especially its unmasking form, remains incompletely described and more data is needed to validate biomarkers for diagnosis. Management strategies remain suboptimal, especially in the highly morbid central nervous system (CNS) form of the disease, and further trials are necessary to refine treatment. In this review we will summarize the current understanding of the immunopathogenesis, the presentation of TB-IRIS and the evidence for management recommendations.

Response of Symptomatic Persistent Chronic Disseminated Candidiasis to Corticosteroid Therapy in Immunosuppressed Pediatric Patients: Case Study and Review of the Literature

BACKGROUND

Chronic disseminated candidiasis (CDC) is a severe invasive fungal infection principally observed during neutrophil recovery in patients with acute leukemia treated with intensive chemotherapy. Its pathophysiology remains unclear. We describe the management of 6 children with symptomatic CDC who did not respond to antifungal therapy.

METHODS

The databases of the hematology-oncology departments of 2 tertiary pediatric medical centers were searched for all patients diagnosed with CDC from 2003 to 2015, who responded to corticosteroids after failing antifungal therapy. Clinical, laboratory and radiologic data were collected.

RESULTS

Six patients (3 women, 3 men; 9-18 years of age) met the study criteria. Underlying diseases were acute lymphoblastic leukemia (n = 3) and large B-cell lymphoma, acute myeloid leukemia and severe aplastic anemia (n = 1 each). Presenting symptoms/signs of CDC were fever in all cases, with abdominal or chest pain, and/or mucositis. Candida infection was identified in blood cultures in 4 patients and in bronchoalveolar lavage fluid in one. In the absence of response to antifungal agents (4-50 days from CDC diagnosis), prednisone 2 mg/kg/day or equivalent was administered. CDC-attributable clinical symptoms resolved in 4 patients within 6-19 days; one patient required an additional nonsteroidal anti-inflammatory agent. Abnormalities on imaging decreased or disappeared within 5 months to 2 years in 4 patients.

CONCLUSIONS

In children with persistent symptomatic CDC, despite adequate antifungal therapy, administration of corticosteroids may yield rapid resolution of symptoms and decreased inflammatory markers. In patients who do not respond to steroids, the addition of a nonsteroidal anti-inflammatory drug should be considered.

Thai national guidelines for antiretroviral therapy in HIV-1 infected adults and adolescents 2010

In Thailand, more than 150,000 patients are currently treated with antiretroviral drugs under the support of the National AIDS Program (NAP). The appointed Adults and Adolescents Committee consisted of 28 members who are experts in HIV research, patient care or health care policy. Relevant published literature, guidelines, and the most recent relevant clinical trials presented internationally were reviewed. Several peer review and clinical studies conducted in Thailand were included in the review process. Special considerations for patients with co-infection of tuberculosis or hepatitis B were incorporated. Appropriate cut-off of CD4+ T-cell counts when to commence ART among Thai patients have been considered. It is now recommended to start ART at CD4+ T-cell count <350 cells/mm3. For treatment-naive patients, the preferred initial therapy is a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen containing lamivudine plus zidovudine or tenofovir. Stavudine will be phased out in a two-year plan at the national program level. Viral load and CD4+ T-cell counts should be monitored at least once and twice a year. To achieve long-term treatment success, enhancing adherence together with the proper management of antiretroviral-related toxicity is critical. In summary, the major changes from the Thai 2008 guidelines include commencing ART earlier. ART is recommended regardless of CD4+ T cell count if patients have an indication to treat their HBV co-infection. Preferred first regimen uses AZT or TDF, not d4T as the NRTI-backbone. Furthermore, efavirenz is now considered a preferred NNRTI, along with nevirapine.

Immune reconstitution inflammatory syndrome in non-HIV immunosuppressed patients

Immune reconstitution inflammatory syndrome (IRIS) represents a clinical phenomenon of immune-mediated inflammation against various antigens, including pathogenic microorganisms, drugs and unknown autoantigens, during recovery from immunosuppressed conditions. IRIS has become well recognized in HIV-infected populations. However, IRIS has seldom been recognized in HIV-negative immunocompromised patients. In the last 15 years, the immunopathogenesis of drug-induced hypersensitivity syndrome (DIHS) has been largely determined. Laboratory data and clinical observations support the idea that DIHS represents a prototype of non-HIV IRIS. Primary diseases in which non-HIV IRIS is secondary include severe cutaneous adverse drug reactions, such as DIHS, autoimmune diseases, collagen diseases, pregnancy and internal malignancies. Potential triggers of recovery from an immune deterioration state include a discontinuation or abrupt tapering of systemic steroids and/or immunosuppressants, withdrawal or reduced effects of anti-tumor necrosis factor-α antibodies, and the use of immune-checkpoint antagonists for the advanced stages of malignancies. Wide use of IRIS across large populations risks oversimplification but highlights a key unifying principle. Balanced sensitivity and specificity for its diagnostic criteria and classification are necessary for the establishment of clinical practice guidelines for non-HIV IRIS. Additionally, the development of a useful combination of biomarkers is currently an urgent issue.

Miliary Tuberculosis

Miliary tuberculosis (TB) results from a massive lymphohematogenous dissemination of Mycobacterium tuberculosis bacilli and is characterized by tiny tubercles evident on gross pathology resembling millet seeds in size and appearance. The global HIV/AIDS pandemic and widespread use of immunosuppressive drugs and biologicals have altered the epidemiology of miliary TB. Considered to be predominantly a disease of infants and children in the pre-antibiotic era, miliary TB is increasingly being encountered in adults as well. The clinical manifestations of miliary TB are protean and nonspecific. Atypical clinical presentation often delays the diagnosis. Clinicians, therefore, should have a low threshold for suspecting miliary TB. Focused, systematic physical examination helps in identifying the organ system(s) involved, particularly early in TB meningitis, as this has therapeutic significance. Fundus examination for detecting choroid tubercles offers a valuable clinical clue for early diagnosis, as their presence is pathognomonic of miliary TB. Imaging modalities help in recognizing the miliary pattern, defining the extent of organ system involvement. Examination of sputum, body fluids, image-guided fine-needle aspiration cytology or biopsy from various organ sites, needle biopsy of the liver, bone marrow aspiration, and biopsy should be done to confirm the diagnosis. Cytopathological, histopathological, and molecular testing (e.g., Xpert MTB/RIF and line probe assay), mycobacterial culture, and drug susceptibility testing must be carried out as appropriate and feasible. Miliary TB is uniformly fatal if untreated; therefore, early initiation of specific anti-TB treatment can be lifesaving. Monitoring for complications, such as acute kidney injury, air leak syndromes, acute respiratory distress syndrome, adverse drug reactions such as drug-induced liver injury, and drug-drug interactions (especially in patients coinfected with HIV/AIDS), is warranted.

Immune reconstitution inflammatory syndrome associated with pulmonary pathogens

Immune reconstitution inflammatory syndrome (IRIS) is an exaggerated immune response to a variety of pathogens in response to antiretroviral therapy-mediated recovery of the immune system in HIV-infected patients. Although IRIS can occur in many organs, pulmonary IRIS, associated with opportunistic infections such as Mycobacterium tuberculosis and Pneumocystis jirovecii, is particularly associated with high morbidity and mortality. The pathology of IRIS is associated with a variety of innate and adaptive immune factors, including CD4⁺ T-cells, CD8⁺ T-cells, γδ T-cells, natural killer cells, macrophages, the complement system and surfactant proteins, Toll-like receptors and pro-inflammatory cytokines and chemokines. Although there are numerous reports about the immune factors involved in IRIS, the mechanisms involved in the development of pulmonary IRIS are poorly understood. Here, we propose that studies using gene-deficient murine and nonhuman primate models will help to identify the specific molecular targets associated with the development of IRIS. An improved understanding of the mechanisms involved in the pathology of pulmonary IRIS will help to identify potential biomarkers and therapeutic targets in this syndrome.

Mechanisms of pulmonary IRIS in HIV-infected individuals recently initiated on ART are poorly definedhttp://ow.ly/AAOR301Bh36

Natalizumab-Related Progressive Multifocal Leukoencephalopathy-Immune Reconstitution Inflammatory Syndrome: A Case Report Highlighting Clinical and MRI Features

Multiple sclerosis (MS) patients treated with natalizumab often face the uncommon but severe complication of developing progressive multifocal leukoencephalopathy (PML). PML may be further complicated by immune reconstitution inflammatory syndrome (IRIS) after the removal of the drug. Since both PML and IRIS are associated with high morbidity and mortality rates, early clinical and radiological diagnosis of these complications is of paramount importance. Here, we report a case of an adult male patient who was diagnosed with PML after receiving natalizumab therapy for 6 years for the treatment of MS. Upon cessation of natalizumab, he presented with a paradoxical worsening of clinical and radiological findings consistent with an inflammatory brain injury due to IRIS. He was treated with high dose corticosteroid therapy followed by a gradual improvement in clinical and imaging findings. This article illustrates the magnetic resonance imaging (MRI) features of natalizumab-associated PML-IRIS, along with a brief overview of its clinical features, complications and management strategies.

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.

Therapeutics targeting inflammation in the immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) is characterized by improvement in a previously incompetent human immune system manifesting as worsening of clinical symptoms secondary to the ability of the immune system to now mount a vigorous inflammatory response. IRIS was first recognized in the setting of human immunodeficiency virus, and this clinical setting continues to be where it is most frequently encountered. Hallmarks of the pathogenesis of IRIS, independent of the clinical presentation and the underlying pathogen, include excessive activation of the immune system, with increased circulating effector memory T cells, and elevated levels of serum cytokines and inflammatory markers. Patients with undiagnosed opportunistic infections remain at risk for unmasking IRIS at the time of active antiretroviral therapy (ART) initiation. Systematic screening for opportunistic infections before starting ART is a key element to prevent this phenomenon. Appropriate management of IRIS requires prompt recognition of the syndrome and exclusion of alternative diagnoses, particularly underlying infections and drug resistance. Controlled studies supporting the use of pharmacologic interventions in IRIS are scare, and recommendations are based on case series and expert opinions. The only controlled trial published to date, showed reduction in morbidity in patients with paradoxical tuberculosis-related IRIS with the use of oral corticosteroids. There are currently limited data to recommend other anti-inflammatory or immunomodulatory therapies that are discussed in this review, and further research is needed. Ongoing research regarding the immune pathogenesis of IRIS will likely direct future rational therapeutic approaches and clinical trials.

Host-Directed Therapies for Tuberculosis

Host-directed therapies are a relatively new and promising approach to treatment of tuberculosis. Modulation of specific host immune pathways, including those that impact inflammation and immunopathology, can limit mycobacterial infection and pathology, both in cell culture and in animal models. This review explores a range of host pathways and drugs, some already approved for clinical use that have the potential to provide new adjunctive therapies for tuberculosis. Drugs targeting host processes may largely avoid the development of bacterial antibiotic resistance, a major public health concern for tuberculosis. However, these drugs may also have generally increased risk for side effects on the host. Understanding the specific mechanisms by which these drugs act and the relationship of these mechanisms to Mycobacterium tuberculosis pathogenesis will be critical in selecting appropriate host-directed therapy. Overall, these host-directed compounds provide a novel strategy for antituberculosis therapy.

Opportunistic infections and immune reconstitution inflammatory syndrome in HIV-1-infected adults in the combined antiretroviral therapy era: a comprehensive review

Despite the availability of effective combined antiretroviral treatment, many patients still present with advanced HIV infection, often accompanied by an AIDS-defining disease. A subgroup of patients starting antiretroviral treatment under these clinical conditions may experience paradoxical worsening of their disease as a result of an exaggerated immune response towards an active (but also subclinical) infectious agent, despite an appropriate virological and immunological response to the treatment. This clinical condition, known as immune reconstitution inflammatory syndrome, may cause significant morbidity and even mortality if it is not promptly recognized and treated. This review updates current knowledge about the incidence, diagnostic criteria, risk factors, clinical manifestations, and management of opportunistic infections and immune reconstitution inflammatory syndrome in the combined antiretroviral treatment era.

Immune reconstitution inflammatory syndrome in HIV-infected patients

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.

Spectrum of central nervous system disorders in hospitalized HIV/AIDS patients (2009-2011) at a major HIV/AIDS referral center in Beijing, China

OBJECTIVE

To describe the spectrum of central nervous system (CNS) disorders and the contribution of neurological immune reconstitution inflammatory syndrome (IRIS) in hospitalized HIV/AIDS patients in You'an Hospital, Beijing China.

STUDY DESIGN & METHODS

A retrospective observational study conducted over a 24-month period in You'an Hospial, a public sector referral hospital in Beijing, China. This study enrolled HIV seropositive patients who were admitted for developing new or recurrent neurological and (or) psychiatric symptoms from September 2009 to August 2011. Medical records were reviewed, demographic and clinical data were collected. Patients with peripheral neuropathy and those in delirium were excluded from this study.

RESULTS

Of the total 620 HIV/AIDS hospital admissions from September 2009 to August 2011, 60 patients (9.7%) were hospitalized for CNS complications. The diagnosis of HIV infection was made after hospital admission in 16 of the 60 patients (26.7%), and 34 of them (56.7%) were already on antiretroviral therapy (ART) at the point of admission. The median CD4 cell count in these subjects was 39 (21-133) cells/mm(3), and 93.3% (56/60) of these patients belonged to stage IV HIV disease according to World Health Organization (WHO) classification. The most frequent diagnosis in these subjects included cryptococcal meningitis (CM, n=13, 22%), cerebral toxoplasmosis (n=10, 17%), and CNS tuberculosis (n=7, 11.7%). The overall mortality was 13% (8/60) and the case-fatality rates were: cryptococcal meningitis 7.7% (1/13), cerebral toxoplasmosis 20% (2/10) and tuberculous meningitis 28.6% (2/7). Of the 34 patients who were on ART, paradoxical neurological IRIS (the conditions of their existing CNS disorders get paradoxically worse after ART because of an exuberant inflammatory response directed towards opportunistic pathogens) was diagnosed in 4 patients (11.8%), 2 of whom related to TB infection (out of 5 TB patients, 40%), and the other 2 related to CM (out of 8 patients, 25%).

CONCLUSION

Opportunistic infections, such as cryptococcal meningitis, cerebral toxoplasmosis and CNS tuberculosis were the most frequent diagnosis of CNS disease in hospitalized HIV/AIDS patients in You'an Hospital, Beijing, China. About 10% patients on ART were diagnosed as neurological IRIS in such a group of patients.

Immune restoration after antiretroviral therapy: the pitfalls of hasty or incomplete repairs

Antiretroviral therapy (ART) is a life-saving intervention in human immunodeficiency virus (HIV) infection. Immune restoration after ART dramatically reduces the incidence and severity of opportunistic diseases and death. On some occasions, immune restoration may be erratic, leading to acute inflammatory responses (known as immune reconstitution inflammatory syndrome) shortly after ART initiation, or incomplete, with residual inflammation despite chronic treatment, leading to non-infectious morbidity and mortality. We propose that ART may not always restore the perfect balance of innate and adaptive immunity in strategic milieus, predisposing HIV-infected persons to complications of acute or chronic inflammation. The best current strategy for fully successful immune restoration is early antiretroviral therapy, which can prevent acquired immunodeficiency syndrome (AIDS)-associated events, restrict cell subset imbalances and dysfunction, while preserving structural integrity of lymphoid tissues. Future HIV research should capitalize on innovative techniques and move beyond the static study of T-cell subsets in peripheral blood or isolated tissues. Improved targeted therapeutic strategies could stem from a better understanding of how HIV perturbs the environmental niches and the mobility and trafficking of cells that affect the dynamic cell-to-cell interactions and determine the outcome of innate and adaptive immune responses.

Matrix metalloproteinases and tissue damage in HIV-tuberculosis immune reconstitution inflammatory syndrome

The HIV-TB-associated immune reconstitution inflammatory syndrome (TB-IRIS) can complicate combined treatments for HIV-1 and TB. Little is known about tissue damage in TB-IRIS. Matrix metalloproteinases (MMPs) degrade components of the extracellular matrix and consequently may play a role in such immunopathology. Here we investigated the involvement of MMPs in TB-IRIS. We determined MMP transcript abundance and secreted protein in Mycobacterium tuberculosis stimulated PBMCs from 22 TB-IRIS patients and 22 non-IRIS controls. We also measured MMP protein levels in corresponding serum and the effect of prednisone--which reduces the duration of symptoms in IRIS patients--or placebo treatment on MMP transcript and circulating MMP protein levels. PBMCs from TB-IRIS had increased MMP-1, -3, -7, and -10 transcript levels when compared with those of controls at either 6 or 24 h. Similarly, MMP-1, -3, -7, and -10 protein secretion in stimulated cultures was higher in TB-IRIS than in controls. Serum MMP-7 concentration was elevated in TB-IRIS and 2 weeks of corticosteroid therapy decreased this level, although not significantly. TB-IRIS is associated with a distinct pattern of MMP gene and protein activation. Modulation of dysregulated MMP activity may represent a novel therapeutic approach to alleviate TB-IRIS in HIV-TB patients undergoing treatment.

Effect of concomitant use of montelukast and efavirenz on neuropsychiatric adverse events

OBJECTIVE

To report the case of an HIV patient who developed neuropsychiatric disturbances when montelukast was added to her therapy containing efavirenz.

CASE SUMMARY

A 41-year-old woman with HIV infection had been on treatment with efavirenz, emtricitabine, and tenofovir disoproxil fumarate since 2007 with good tolerance. In November 2011, montelukast was started for asthma and shortly thereafter neuropsychiatric symptoms appeared, consisting of disturbed sleep, vivid dreams, irritability, confusion, and concentration difficulties. In January 2012, 2 months after the introduction of montelukast, she continued to report unbearable symptoms without any improvement; so, montelukast was withdrawn and the psychiatric symptoms completely disappeared.

DISCUSSION

The combination of efavirenz and montelukast has not previously been associated with any pharmacokinetic interactions or worsening of neuropsychiatric symptoms. This case report indicates the possibility of adverse effects developing when the 2 drugs are used together. These symptoms might either be related to a drug-drug interaction or increased by the similar side effect profiles of the 2 drugs. The higher score on the Karch-Lasagna scale suggests that an adverse effect is the more likely explanation. We cannot, however, rule out a drug interaction, given that efavirenz inhibits the CYP 2C9, 2C19, and 3A4 isoenzymes and CYP 3A4, 2C9, and 2C8 are involved in the metabolism of montelukast.

CONCLUSIONS

Considering that efavirenz is frequently used in antiretroviral therapy and that neuropsychiatric symptoms can limit its use, clinicians should consider the possibility of worsening of these symptoms, such as mood disorders and abnormal dreams, when montelukast is introduced.

The immunopathogenesis of the HIV tuberculosis immune reconstitution inflammatory syndrome

HIV-1 patients co-infected with some pathogens are at risk of developing the immune reconstitution inflammatory syndrome (IRIS) when initiating antiretroviral therapy (ART). IRIS is characterized by inflammation leading to the clinical worsening of a treated infection or the unmasking of a previously undiagnosed condition or infection. It is commonly associated with tuberculosis (TB), 8-43% of the HIV-TB co-infected patients prescribed with antitubercular treatment and ART develop TB-IRIS. Although IRIS has been recognized for over 20 years, relatively little was known until recently about its pathogenesis. Despite these advances in understanding IRIS, there remains no immune biomarker for diagnostic or prognostic purposes. Here, we review the risk factors associated with TB-IRIS, the challenges in studying this syndrome, and how T lymphocytes, dysregulated cytokine responses, and innate immunity may contribute to the development of TB-IRIS.

Paradoxical Mycobacterium tuberculosis meningitis immune reconstitution inflammatory syndrome in an HIV-infected child

Immune reconstitution inflammatory syndrome occurs in a subset of HIV-infected individuals as the immune system recovers secondary to antiretroviral therapy. An exaggerated and uncontrolled inflammatory response to antigens of viable or nonviable organisms is characteristic, with clinical deterioration despite improvement in laboratory indicators. We describe a fatal case of Mycobacterium tuberculosis meningitis immune reconstitution inflammatory syndrome in an HIV-infected child and review the literature.

HIV-1 and the immune response to TB

TB causes 1.4 million deaths annually. HIV-1 infection is the strongest risk factor for TB. The characteristic immunological effect of HIV is on CD4 cell count. However, the risk of TB is elevated in HIV-1 infected individuals even in the first few years after HIV acquisition and also after CD4 cell counts are restored with antiretroviral therapy. In this review, we examine features of the immune response to TB and how this is affected by HIV-1 infection and vice versa. We discuss how the immunology of HIV-TB coinfection impacts on the clinical presentation and diagnosis of TB, and how antiretroviral therapy affects the immune response to TB, including the development of TB immune reconstitution inflammatory syndrome. We highlight important areas of uncertainty and future research needs.

HIV peripheral neuropathy

Peripheral neuropathies are the most common neurological manifestations occurring in HIV-infected individuals. Distal symmetrical sensory neuropathy is the most common form encountered today and is one of the few that are specific to HIV infection or its treatment. The wide variety of other neuropathies is akin to the neuropathies seen in the general population and should be managed accordingly. In the pre-ART era, neuropathies were categorized according to the CD4 count and HIV viral load. In the early stages of HIV infection when CD4 count is high, the inflammatory demyelinating neuropathies predominate and in the late stages with the decline of CD4 count opportunistic infection-related neuropathies prevail. That scenario has changed with the present almost universal use of ART (antiretroviral therapy). Hence, HIV-associated peripheral neuropathies are better classified according to their clinical presentations: distal symmetrical polyneuropathy, acute inflammatory demyelinating polyradiculoneuropathy (AIDP) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), mononeuropathies, mononeuropathies multiplex and cranial neuropathies, autonomic neuropathy, lumbosacral polyradiculomyelopathy, and amyotrophic lateral sclerosis (ALS)-like motor neuropathy. Treated with ART, HIV-infected individuals are living longer and are at a higher risk of metabolic and age-related complications; moreover they are also prone to the potentially neurotoxic effects of ART. There are no epidemiological data regarding the incidence and prevalence of the peripheral neuropathies. In the pre-ART era, most data were from case reports, series of patients, and pooled autopsy data. At that time the histopathological evidence of neuropathies in autopsy series was almost 100%. In large prospective cohorts presently being evaluated, it has been found that 57% of HIV-infected individuals have distal symmetrical sensory neuropathy and 38% have neuropathic pain. It is now clear that distal symmetrical sensory neuropathy is caused predominantly by the ART's neurotoxic effect but may also be caused by the HIV itself. With a sizeable morbidity, the neuropathic pain caused by distal symmetrical sensory neuropathy is very difficult to manage; it is often necessary to change the ART regimen before deciding upon the putative role of HIV infection itself. If the change does not improve the pain, there are few options available; the most common drugs used for neuropathic pain are usually not effective. One is left with cannabis, which cannot be recommended as routine therapy, recombinant human nerve growth factor, which is unavailable, and topical capsaicin with its side-effects. Much has been done to and learned from HIV infection in humans; HIV-infected individuals, treated with ART, are now dying mostly from cardiovascular disease and non-AIDS-related cancers. It hence behooves us to find new approaches to mitigate the residual neurological morbidity that still impacts the quality of life of that population.

Management of the immune reconstitution inflammatory syndrome

The immune reconstitution inflammatory syndrome (IRIS) is a frequent early complication of antiretroviral therapy (ART) in patients with advanced HIV. Because there is no confirmatory diagnostic test, the diagnosis is based on clinical presentation and exclusion of alternative causes for deterioration, such as antimicrobial drug resistance. Opportunistic infection treatment should be optimized. Mild cases may require symptomatic therapy alone or nonsteroidal anti-inflammatory drugs. Corticosteroids have been used to treat more severe cases of IRIS associated with mycobacterial and fungal infections. There is evidence from a randomized controlled trial that prednisone reduces morbidity and improves symptoms in paradoxical tuberculosis (TB)-IRIS. Neurological TB-IRIS is potentially life-threatening; high-dose corticosteroids are indicated and ART interruption should be considered if level of consciousness is depressed. When considering corticosteroid treatment clinicians should be aware of their side effects and only use them when the diagnosis of IRIS is certain. In viral forms of IRIS corticosteroids are generally avoided.

Pathogenesis of the immune reconstitution inflammatory syndrome in HIV-infected patients

PURPOSE OF REVIEW

The immune reconstitution inflammatory syndrome (IRIS) is an important clinical complication in HIV-infected patients initiating antiretroviral therapy. This review focuses on the latest literature pertaining to the pathogenesis of IRIS.

RECENT FINDINGS

The clinical manifestations of IRIS are heterogeneous due to the variety of opportunistic infections that are associated with this inflammatory syndrome. However, the disproportionate inflammation is a defining hallmark for which common mechanisms are suspected. Lymphopenia-induced proliferation in the context of systemic immune activation, presence of high antigenic exposure and a wider availability of interleukin-7 contribute to the exacerbated immune response underlying IRIS. Defect in pathogen clearance by phagocytes might favor high pathogen burden, which in turn is thought to activate both innate immune cells and pathogen-specific T cells upon correction of the CD4 T-cell lymphopenia, predisposing to IRIS. This common scenario might be further invigorated by functional impairments among regulatory T cells.

SUMMARY

Further insight into the cellular mechanisms driving IRIS is urgently needed. Understanding the relative contribution of distinct effector and regulatory T-cell subsets, and innate immune components to IRIS is required to inspire future therapeutic approaches.

Pathogenesis and prevention of immune reconstitution disease during antiretroviral therapy

The risks of unmasking and paradoxical forms of immune reconstitution disease in HIV-infected patients starting antiretroviral therapy (ART) are fuelled by a combination of the late presentation of patients with advanced immunodeficiency, the associated high rates of opportunistic infections (OIs) and the need for rapid initiation of ART to minimize overall mortality risk. We review the risk factors and our current knowledge of the immunopathogenesis of immune reconstitution disease, leading to a discussion of strategies for prevention. Initiation of ART at higher CD4 counts, use of OI-preventive therapies prior to ART eligibility, intensified screening for OIs prior to ART initiation and optimum therapy for OIs are all needed. In addition, use of a range of pharmacological agents with immunosuppressive and immunomodulatory activity is being explored.

HIV and tuberculosis: a deadly human syndemic

A syndemic is defined as the convergence of two or more diseases that act synergistically to magnify the burden of disease. The intersection and syndemic interaction between the human immunodeficiency virus (HIV) and tuberculosis (TB) epidemics have had deadly consequences around the world. Without adequate control of the TB-HIV syndemic, the long-term TB elimination target set for 2050 will not be reached. There is an urgent need for additional resources and novel approaches for the diagnosis, treatment, and prevention of both HIV and TB. Moreover, multidisciplinary approaches that consider HIV and TB together, rather than as separate problems and diseases, will be necessary to prevent further worsening of the HIV-TB syndemic. This review examines current knowledge of the state and impact of the HIV-TB syndemic and reviews the epidemiological, clinical, cellular, and molecular interactions between HIV and TB.

Pulmonary manifestations of the immune reconstitution inflammatory syndrome

PURPOSE OF REVIEW

Immune reconstitution inflammatory syndrome (IRIS) is a common occurrence in HIV patients starting antiretroviral therapy (ART), and pulmonary involvement is an important feature of tuberculosis-IRIS and pneumocystis-IRIS. Pulmonologists need an awareness of the timing, presentation and treatment of pulmonary IRIS.

RECENT FINDINGS

Case definitions for tuberculosis-IRIS and cryptococcal-IRIS have been published by the International Network for the Study of HIV-associated IRIS (INSHI). A number of studies have addressed validation of clinical case definitions and the optimal time to commence ART after diagnosis of an opportunistic infection in HIV patients. The pathogenesis of IRIS is being assessed at a molecular level, increasing our understanding of mechanisms and possible targets for future preventive and therapeutic strategies.

SUMMARY

Tuberculosis-IRIS, nontuberculosis mycobacterial-IRIS and pneumocystis-IRIS occur within days to weeks of starting ART, causing substantial morbidity, but low mortality. Cryptococcal-IRIS usually occurs later in the course of ART, and may be associated with appreciable mortality. Early recognition of unmasking and paradoxical IRIS affecting the lung allows timely initiation of antimicrobial and/or immunomodulatory therapies.

Hypercytokinaemia accompanies HIV-tuberculosis immune reconstitution inflammatory syndrome

Increased access to combination antiretroviral therapy in areas co-endemic for tuberculosis (TB) and HIV-1 infection is associated with an increased incidence of immune reconstitution inflammatory syndrome (TB-IRIS) whose cause is poorly understood. A case-control analysis of pro- and anti-inflammatory cytokines in TB-IRIS patients sampled at clinical presentation, and similar control patients with HIV-TB prescribed combined antiretroviral therapy who did not develop TB-IRIS. Peripheral blood mononuclear cells were cultured in the presence or absence of heat-killed Mycobacterium tuberculosis for 6 and 24 h. Stimulation with M. tuberculosis increased the abundance of many cytokine transcripts with interleukin (IL)-1β, IL-5, IL-6, IL-10, IL-13, IL-17A, interferon (IFN)-γ, granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumour necrosis factor (TNF) being greater in stimulated TB-IRIS cultures. Analysis of the corresponding proteins in culture supernatants, revealed increased IL-1β, IL-2, IL-6, IL-8, IL-10, IL-12p40, IFN-γ, GM-CSF and TNF in TB-IRIS cultures. In serum, higher concentrations of TNF, IL-6, and IFN-γ were observed in TB-IRIS patients. Serum IL-6 and TNF decreased during prednisone therapy in TB-IRIS patients. These data suggest that cytokine release contributes to pathology in TB-IRIS. IL-6 and TNF were consistently elevated and decreased in serum during corticosteroid therapy. Specific blockade of these cytokines may be rational approach to immunomodulation in TB-IRIS.

The immune reconstitution inflammatory syndrome and antiretroviral therapy

Although generally mild, severe immune reconstitution inflammatory syndrome may complicate antiretroviral therapy, and it may be difficult to differentiate from treatment failure or toxicity. This article looks at diagnostic and therapeutic challenges of severe infectious manifestations of immune reconstitution inflammatory syndrome.

Antiretroviral treatment 2010: progress and controversies

Effective antiretroviral therapy (ART) changes the clinical course of HIV infection. There are 25 antiretroviral drugs approved for the treatment of HIV infection, and current antiretroviral drug regimens are highly effective, convenient, and relatively nontoxic. ART regimens should be chosen in consideration of a patient's particular clinical situation. Successful treatment is associated with durable suppression of HIV viremia over years, and consequently, ART reduces the risk of clinical progression. In fact, current models estimate that an HIV-infected individual appropriately treated with antiretroviral drugs has a life expectancy that approaches that of the general HIV-uninfected population, although some patient groups such as injection drug users do less well. Despite these advances, continued questions about ART persist: What is the optimal time to start ART? What is the best regimen to start? When is the optimal time to change ART? What is the best regimen to change to? In addition, newer antiretroviral agents are in development, both in existing classes and in new classes such as the CD4 receptor attachment inhibitors and the maturation inhibitors. Further research will help optimize current antiretroviral treatments and strategies.

Recognition of immune reconstitution syndrome necessary for better management of patients with severe drug eruptions and those under immunosuppressive therapy

The immune reconstitution syndrome (IRS) is an increasingly recognized disease concept and is observed with a broad-spectrum of immunosuppressive therapy-related opportunistic infectious diseases and severe drug eruptions complicated by viral reactivations. Clinical illness consistent with IRS includes tuberculosis, herpes zoster, herpes simples, cytomegalovirus infections and sarcoidosis: thus, the manifestations of this syndrome and diverse and depend on the tissue burden of the preexisting infectious agents during the immunosuppressive state, the nature of the immune system being restored, and underlying diseases of the hosts. Although IRS has originally been reported to occur in the setting of HIV infection, it has become clear that the development of IRS can also be in HIV-negative hosts receiving immunosuppressive agents, such as prednisolone and tumor necrosis factor α inhibitors, upon their reduction and withdrawal. Drug-induced hypersensitivity syndrome, a life-threatening multiorgan system reaction, is another manifestation of the newly observed IRS. Clinical recognition of the IRS is especially important in improving the outcome for diseases with an otherwise life-threatening progenosis. Clinicians should be aware of the implications of IRS and recognize that relieving the symptoms and signs of immune recovery by anti-inflammatory therapies needs to be balanced with anti-microbial therapies aiming at reducing the amplitude and duration of tissue burden of preexisting microbes.

Central nervous system disorders after starting antiretroviral therapy in South Africa

OBJECTIVE

To describe the spectrum of central nervous system (CNS) disease during the first year of antiretroviral therapy (ART) and to determine the contribution of neurological immune reconstitution inflammatory syndrome (IRIS).

DESIGN

A prospective observational cohort study conducted over a 12-month period at a public sector referral hospital in South Africa.

METHODS

HIV-seropositive patients who developed new or recurrent neurological or psychiatric symptom(s) or sign(s) within the first year of starting ART were enrolled. We used the number of patients starting ART in the referral area in the preceding year as the denominator to calculate the incidence of referral for neurological deterioration. Patients with delirium and peripheral neuropathy were excluded. Outcome at 6 months was recorded.

RESULTS

Seventy-five patients were enrolled. The median nadir CD4(+) cell counts was 64 cells/μl. Fifty-nine percent of the patients were receiving antituberculosis treatment. The incidence of referral for CNS deterioration in the first year of ART was 23.3 cases [95% confidence interval (CI), 18.3-29.2] per 1000 patient-years at risk. CNS tuberculosis (n = 27, 36%), cryptococcal meningitis (n = 18, 24%), intracerebral space occupying lesions (other than tuberculoma) (n = 10, 13%) and psychosis (n = 9, 12%) were the most frequent diagnoses. Paradoxical neurological IRIS was diagnosed in 21 patients (28%), related to tuberculosis in 16 and cryptococcosis in five. At 6 months, 23% of the patients had died and 20% were lost to follow-up.

CONCLUSION

Opportunistic infections, notably tuberculosis and cryptococcosis, were the most frequent causes for neurological deterioration after starting ART. Neurological IRIS occurred in over a quarter of patients.

HIV-associated tuberculous meningitis--diagnostic and therapeutic challenges

HIV-associated tuberculous meningitis (TBM) poses significant diagnostic and therapeutic challenges and carries a dismal prognosis. In this review, we present the clinical features and management of HIV-associated TBM, and compare this to disease in HIV-uninfected individuals. Although the clinical presentation, laboratory findings and radiological features of TBM are similar in HIV-infected and HIV-uninfected patients, some important differences exist. HIV-infected patients present more frequently with extra-meningeal tuberculosis and systemic features of HIV infection. In HIV-associated TBM, clinical course and outcome are influenced by profound immunosuppression at presentation, emphasising the need for earlier diagnosis of HIV infection and initiation of antiretroviral treatment.

Genetic characterization of HIV type 1 among patients with suspected immune reconstitution inflammatory syndrome after initiation of antiretroviral therapy in Kenya

Antiretroviral therapy (ART) has improved the survival of HIV patients but is also associated with unique manifestations of disease in some subjects during the initial months of therapy. Immune reconstitution inflammatory syndrome (IRIS) is a disorder among individuals starting ART, with no evidence-based treatment and management guidelines. We characterized HIV-1 and determined drug resistance among 14 Kenyan patients with suspected IRIS after ART initiation in 2005. Polymerase chain reaction, sequencing, and phylogenetic analysis of viral pol and env showed the following HIV-1 subtypes: A1/A1/A1 (pol-RT/gp41/C2V3), 5; A1/C/A1, 1; A1/D/A1, 2; D/A1/A1, 1; D/C/A1, 1; D/D/A1, 2; D/D/D, 1; and D/A1/A2, 1. Three patients had viruses with major drug resistance-associated mutations. These included nucleoside reverse transcriptase inhibitor (RTI) mutations: M41L, K65R, D67N, K70R, M184V, and K219Q, and nonnucleoside RTI mutations: K101P, L100I, K103N, and Y181C. Twelve patients harbored viruses that are predicted to use chemokine coreceptor 5 (CCR5) whereas two had variant viruses predicted to use the CXCR4 coreceptor. Drug resistance may not be the only cause of ART adverse events. HIV-1 characterization would be important before and during HIV therapy to avoid treatment failure.