Immune restoration inflammatory syndromes: Apparently paradoxical clinical events after the initiation of HAART

The current understanding of overlap between characteristics of HIV-associated neurocognitive disorders and Alzheimer's disease

The advent of effective antiretroviral medications (ARVs) has led to an aging of the HIV population with approximately 50% of people with HIV (PWH) being over the age of 50 years. Neurocognitive complications, typically known as HIV-associated neurocognitive disorders (HAND), persist in the era of ARVs and, in addition to risk of HAND, older PWH are also at risk for age-associated, neurodegenerative disorders including Alzheimer's disease (AD). It has been postulated that risk for AD may be greater among PWH due to potential compounding effects of HIV and aging on mechanisms of neural insult. We are now faced with the challenge of disentangling AD from HAND, which has important prognostic and treatment implications given the more rapidly debilitating trajectory of AD. Herein, we review the evidence to date demonstrating both parallels and differences in the profiles of HAND and AD. We specifically address similarities and difference of AD and HAND as it relates to (1) neuropsychological profiles (cross-sectional/longitudinal), (2) AD-associated neuropathological features as evidenced from neuropathological, cerebrospinal fluid and neuroimaging assessments, (3) biological mechanisms underlying cortical amyloid deposition, (4) parallels in mechanisms of neural insult, and (5) common risk factors. Our current understanding of the similarities and dissimilarities of AD and HAND should be further delineated and leveraged in the development of differential diagnostic methods that will allow for the early identification of AD and more suitable and effective treatment interventions among graying PWH.

Extracorporeal Membrane Oxygenation in a 29-Year-Old Man with Pneumocystis jirovecii Respiratory Failure and AIDS

The use of extracorporeal membrane oxygenation (ECMO) in patients who have acute respiratory distress syndrome has been generally beneficial. However, because of various concerns, ECMO has rarely been used in patients who have human immunodeficiency virus infection with or without acquired immune deficiency syndrome. We report our successful use of venovenous ECMO in a 29-year-old man who presented with severe respiratory distress secondary to Pneumocystis jirovecii pneumonia associated with undiagnosed infection with the human immunodeficiency virus and acquired immune deficiency syndrome. After highly active antiretroviral therapy was begun, acute immune reconstitution inflammatory syndrome developed. The patient's respiratory condition deteriorated rapidly; he was placed on venovenous ECMO for 19 days and remained intubated thereafter. After a 65-day hospital stay and inpatient pulmonary rehabilitation, he recovered fully. In addition to presenting this case, we review the few previous reports and note the multidisciplinary medical and surgical support necessary to treat similar patients.

A non-synonymous polymorphism in IL-23R Gene (rs1884444) is associated with reduced risk to schistosomiasis-associated Immune Reconstitution Inflammatory Syndrome in a Kenyan population

Background

Human Immunodeficiency Virus (HIV) and Schistosomiasis co-infection is common among residents at the shores of Lake Victoria in Kenya. About 36% of this population initiating antiretroviral therapy (ART) experience Immune Reconstitution Inflammatory Syndrome (IRIS) that complicates recovery. Several IL-23R alleles have been associated with susceptibility to both autoimmune and inflammatory diseases through T-helper type 17 (TH₁₇) cells. However, whether or not variants within the IL-23R increase susceptibility to IRIS in western Kenya is unknown. The objective of the current study was to determine the association between IL-23R gene polymorphisms, CD4+ cell counts and HIV RNA levels and IRIS in HIV and Schistosoma mansoni co-infected patients undergoing highly active anti-retroviral therapy (HAART).

Methods

A three-month case–control study was conducted on antiretroviral naïve schistosomiasis/HIV co-infected fishermen starting HAART in Uyoma Rarieda, Siaya County, Kenya. Seventy one patients were sampled at baseline and followed up for three months, to establish if they developed Schistosoma-related IRIS. In addition, the CD4+ cell counts and HIV RNA levels were determined in pre- and post-administration of HAART. Variations at five polymorphic sites of IL-23R (rs1884444, rs11465754, rs6682925, rs7530511 and rs7539625) based on >10% minor allele frequency in Yoruban reference population was determined using Allelic Discrimination Assay. The association between the five variants and susceptibility to IRIS was determined using logistic regression while controlling for potential confounders. In addition, the functional differences between the baseline CD4 + Cell counts and viral loads were determined using medians while across IL-23R genotypes were determined using Kruskal-Wallis tests.

Results

Overall, 26 (36.6%) patients developed schistosomiasis-associated IRIS at a median age of 35.5 years. Carriage of the TT genotype at the non-synonymous rs1884444 T > G relative to GG, was associated with a decreased risk of schistosomiasis-associated IRIS (OR, 0.25, 95% CI, 0.07-0.96, P = 0.043) while both baseline CD4+ cell counts and viral loads had no association with IRIS.

Conclusion

These findings indicate that the non-synonymous variant rs1884444 T > G of IL-23R is associated with a decreased risk to schistosomiasis-associated IRIS. However, additional studies in a larger cohort and with an all inclusive polymorphic variants in the synonymous and non-synonymous regions need to be evaluated.

CNS-immune reconstitution inflammatory syndrome in the setting of HIV infection, part 2: discussion of neuro-immune reconstitution inflammatory syndrome with and without other pathogens

SUMMARY

While the previous review of CNS-IRIS in the HIV-infected patient on highly active antiretroviral therapy (Part 1) dealt with an overview of the biology, pathology, and neurologic presentation of this condition and a discussion of the atypical imaging findings in PML-IRIS and cryptococcal meningitis-IRIS due to the robust inflammatory response, the current review (Part 2) discusses the imaging findings in other commonly encountered organisms seen in association with CNS-IRIS, namely, VZV, CMV, HIV, Candida organisms, Mycobacterium tuberculosis, and Toxoplasma gondii. Also described is the imaging appearance of CNS-IRIS when not associated with a particular organism. Recognition of these imaging findings will give credence to the diagnosis of CNS-IRIS and will allow the clinician to institute changes in medical management, if necessary, so that immune reconstitution and improved patient outcome can occur with time.

Clinical review: Respiratory failure in HIV-infected patients--a changing picture

Respiratory failure in HIV-infected patients is a relatively common presentation to ICU. The debate on ICU treatment of HIV-infected patients goes on despite an overall decline in mortality amongst these patients since the AIDS epidemic. Many intensive care physicians feel that ICU treatment of critically ill HIV patients is likely to be futile. This is mainly due to the unfavourable outcome of HIV patients with Pneumocystis jirovecii pneumonia who need mechanical ventilation. However, the changing spectrum of respiratory illness in HIV-infected patients and improved outcome from critical illness remain under-recognised. Also, the awareness of certain factors that can affect their outcome remains low. As there are important ethical and practical implications for intensive care clinicians while making decisions to provide ICU support to HIV-infected patients, a review of literature was undertaken. It is notable that the respiratory illnesses that are not directly related to underlying HIV disease are now commonly encountered in the highly active antiretroviral therapy (HAART) era. The overall incidence of P. jirovecii as a cause of respiratory failure has declined since the AIDS epidemic and sepsis including bacterial pneumonia has emerged as a frequent cause of hospital and ICU admission amongst HIV patients. The improved overall outcome of HIV patients needing ICU admission is related to advancement in general ICU care, including adoption of improved ventilation strategies. An awareness of respiratory illnesses in HIV-infected patients along with an appropriate diagnostic and treatment strategy may obviate the need for invasive ventilation and improve outcome further. HIV-infected patients presenting with respiratory failure will benefit from early admission to critical care for treatment and support. There is evidence to suggest that continuing or starting HAART in critically ill HIV patients is beneficial and hence should be considered after multidisciplinary discussion. As a very high percentage (up to 40%) of HIV patients are not known to be HIV infected at the time of ICU admission, the clinicians should keep a low threshold for requesting HIV testing for patients with recurrent pneumonia.

CNS-immune reconstitution inflammatory syndrome in the setting of HIV infection, part 1: overview and discussion of progressive multifocal leukoencephalopathy-immune reconstitution inflammatory syndrome and cryptococcal-immune reconstitution inflammatory syndrome

SUMMARY

While uncommon, CNS-IRIS developing after the initiation of HAART in the setting of HIV-related severe immunosuppression is characterized by an intense inflammatory reaction to dead or latent organisms or to self-antigens due to a heightened but dysregulated immune response. While this reaction can range from mild to fulminating, encompassing a very wide clinical spectrum, it is important to recognize because changes in medical management may be necessary to prevent neurologic decline and even death. Once contained, however, this inflammatory response can be associated with improved patient outcome as immune function is restored. Among the infectious organisms that are most commonly associated with CNS-IRIS are the JC virus and Cryptococcus organisms, which will be the subject of this review. CD8 cell infiltration in the leptomeninges, perivascular spaces, blood vessels, and even parenchyma seems to be the pathologic hallmark of CNS-IRIS. While recognition of CNS-IRIS may be difficult, the onset of new or progressive clinical symptoms, despite medical therapy and despite improved laboratory data, and the appearance on neuroimaging studies of contrast enhancement, interstitial edema, mass effect, and restricted diffusion in infections not typically characterized by these findings in the untreated HIV-infected patient should raise the strong suspicion for CNS-IRIS. While CNS-IRIS is a diagnosis of exclusion, the neuroradiologist can play a critical role in alerting the clinician to the possibility of this syndrome.

[Immune reconstitution syndrome]

The immune reconstitution inflammatory syndrome (IRIS) represents a heterogeneous group of conditions. Whilst they typically present in HIV-infected patients with advanced immunodeficiency, IRIS have also been described in HIV-negative patients with immune reconstitution due to other causes of immunosuppression. Frequently IRIS results from an immune response against underlying infection (pathogen-associated IRIS). However, IRIS might become evident during immune reconstitution without an underlying pathogen such as a sarcoid-like illness or an autoimmune thyropathy. Here we report on the epidemiology and risk factors of IRIS along with diagnosis and management of this clinically important inflammatory syndrome.

JC virus infection of the brain

Since its initial description, there have been significant changes in the epidemiology, pathogenesis, and clinical and imaging manifestations of JCV infection of brain. The most common clinical manifestation is PML. Other recently described CNS manifestations are JCE, JCVGCN, and JCM. Although AIDS is the most common predisposing factor for JCV reactivation, there is increasing incidence of brain manifestations of JCV reactivation in non-HIV settings, including different rheumatologic, hematologic, and oncologic conditions; monoclonal antibody therapy; transplant recipients; primary immunodeficiency syndromes; and even in patients without any recognizable immune deficiency. IRIS may develop secondary to restoration of immunity in HIV-positive patients with PML receiving antiretroviral therapy. This is of profound clinical significance and needs to be diagnosed promptly. Imaging plays a crucial role in the diagnosis of the disease, monitoring of treatment response, identifying disease progression, and predicting prognosis. In this article, current understanding of the epidemiology, pathogenesis, clinical presentations, and all aspects of imaging of JCV infection of the brain have been comprehensively reviewed.

[Severe aseptic leucoencephalopathy. Manifested as immune reconstitution inflammatory syndrome in Caucasian and African patients]

BACKGROUND

We hypothesize that CNS immune reconstitution inflammatory syndrome (IRIS) after highly active antiretroviral therapy (HAART) in HIV-1-positive patients may become manifest without any opportunistic infection as an aseptic leucoencephalopathy. This opens a window of opportunity for successful treatment with corticosteroids.

DESIGN

We describe a case series of immunocompromised HIV-1-positive patients who were started on HAART. All of them had clinical laboratory follow-up tests and cerebral MRI in order to investigate the course and the underlying pathophysiology of this aseptic form of IRIS. One African patient died and we performed a neuropathological examination.

RESULTS

No infectious agent was detected before and during HAART. Three of four immunocompromised patients were successfully treated with corticosteroids while HAART was never interrupted and have survived up to now. One African patient died within 2 days despite intensive care due to cerebral oedema.

CONCLUSIONS

Starting HAART, HIV-1-positive patients may develop an aseptic type of IRIS of the CNS without any detectable opportunistic infection, a finding that has not yet been published. This makes them susceptible for successful treatment with corticosteroids. Perhaps IRIS has a higher incidence in African patients and the patients have a poorer outcome than Caucasians.

[Acute renal failure and hypercalcemia in an AIDS patient on tenofovir and low-dose vitamin D therapy with immune reconstitution inflammatory syndrome]

BACKGROUND

Tenofovir-containing antiviral therapy might result in acute renal failure and is able to induce tubular dysfunction with hypocalcemia. On the other hand, hypercalcemia induced by intoxication with colecalciferol has been described to induce renal failure in HIV-positive individuals as well. Here, the authors describe the unusual case of reversible renal failure due to hypercalcemia in a patient with low-dose colecalciferol substitution treated with tenofovir.

CASE REPORT

A 31-year-old HIV-positive female, CDC stage C3, was admitted to the authors' hospital with progressive renal failure and hypercalcemia. Antiretroviral therapy consisted of tenofovir and emtricitabine in combination with efavirenz. Additionally, she was on low-dose vitamin D(3) substitution (25 microg/d) and calcium supplementation (500 mg/d) due to systemic steroid treatment.

CONCLUSION

Additionally to regular control of renal function, serologic level of calcium should be supervised in patients concomitantly treated with tenofovir and colecalciferol.

Severe aseptic leucoencephalopathy as immune reconstitution inflammatory syndrome in Caucasian and African patients

Immune reconstitution inflammatory syndrome (IRIS) after HAART may become manifest in form of aseptic severe leucoencephalopathy. All HIV-1-positive patients in this case series had widespread laboratory tests and follow-up MRI in order to investigate the course and the underlying pathophysiology of IRIS-associated leucoencephalopathy. All patients were treated with corticosteroids, in spite of additional immunosuppression. Three patients were successfully treated with corticosteroids and survived up to now, one died. A neuropathological examination was performed showing massive aseptic intraparenchymal and perivascular invasion of cytotoxic CD8 cells. It is assumed that IRIS-associated leucoencephalopathy is based on other preconditions in Africans and Caucasians.

The comorbidity of HIV-associated neurocognitive disorders and Alzheimer's disease: a foreseeable medical challenge in post-HAART era

Although the introduction of highly active antiretroviral therapy (HAART) has led to a strong reduction of HIV-associated dementia (HAD) incidence, the prevalence of minor HIV-1-associated neurocognitive disorder (HAND) is rising among AIDS patients. HAART medication has shifted neuropathology from a subacute encephalitic condition to a subtle neurodegenerative process involving synaptic and dendritic degeneration, particularly of hippocampal neurons that are spared prior to HAART medication. Considerable neuroinflammation coupled with mononuclear phagocyte activation is present in HAART-medicated brains, particularly in the hippocampus. Accumulating evidence suggests that the resultant elevated secretion of pro-inflammatory cytokines such as interferon-gamma, tumor necrosis factor-alpha, and interleukin-1beta can increase amyloid-beta peptide (Abeta) generation and reduce Abeta clearance. Recent advancements in Alzheimer's disease (AD) research identified Abeta biogenesis and clearance venues that are potentially influenced by HIV viral infection, providing new insights into beta-amyloidosis segregation in HIV patients. Our study suggests enhanced beta-amyloidosis in ART-treated HAD and HIV-associated encephalitis brains and suppression of Abeta clearance by viral infection of human primary macrophages. A growing awareness of potential convergent mechanisms leading to neurodegeneration shared by HIV and Abeta points to a significant chance of comorbidity of AD and HAND in senile HIV patients, which calls for a need of basic studies.

Immune activation and inflammation in HIV-1 infection: causes and consequences

Thorough research on HIV is progressively enabling us to understand the intricate mechanisms that link HIV-1 infection to the onset of immunodeficiency. The infection and depletion of CD4(+) T cells represent the most fundamental events in HIV-1 infection. However, in recent years, the role played by chronic immune activation and inflammation in HIV pathogenesis has become increasingly apparent: quite paradoxically, immune activation levels are directly associated with HIV-1 disease progression. In addition, HIV-1-infected patients present intriguing similarities with individuals of old age: their immune systems are characterized by a loss of regenerative capacity and an accumulation of ageing T cells. In this review, we discuss the potential reasons for the establishment of sustained immune activation and inflammation from the early stages of HIV-1 infection, as well as the long-term consequences of this process on the host immune system and health. A simplified model of HIV pathogenesis is proposed, which links together the three major facets of HIV-1 infection: the massive depletion of CD4(+) T cells, the paradoxical immune activation and the exhaustion of regenerative capacity.

Evolution of HIV dementia with HIV infection

Dementia remains one of the most fearsome complications of HIV infection. It also poses a significant challenge for the clinician both in terms of diagnosis and treatment. The use of antiretroviral agents has led to a decrease in the incidence of HIV dementia but the prevalence of milder forms of neurocognitive impairment has increased. Occasionally, the immune reconstitution caused by these agents may target the brain leading to a syndrome characterized by a severe, progressive and often fatal dementia. The progression of HIV dementia may also be determined by host and viral genetic factors, and the existence of co-morbid factors such as drug abuse, hepatitis C infection and aging. Oxidative stress markers appear to be predictive of active dementia. However, currently there is no specific treatment available for HIV dementia.

Thoracic manifestations of immune restoration syndromes in AIDS

Immune restoration syndromes (IRS) in AIDS constitute a group of illness characterized by a pathologic inflammatory response in patients with late-stage AIDS who start highly active antiretroviral therapy. Although there is no standardized definition or therapy, IRS have partial immune restoration associated with an increase in their CD-4 cell count and a decrease in their viral load. Patients with IRS show a paradoxical reaction that is, clinical worsening rather than improvement on therapy, associated with a recognized or occult infection. Symptoms include new or worsening fever, lymphadenopathy, pulmonary, visceral, central nervous system, or cutaneous disease which may be severe and occasionally life threatening and must be differentiated from disease progression. In this paper, we review the clinical and associated thoracic imaging findings of IRS associated with specific infections including mycobacterial and fungal infections, cytomegalovirus, Pneumocystis jiroveci pneumonia and also Kaposi sarcoma and sarcoidosis. Recognition of the imaging findings in the appropriate clinical setting presents an opportunity to make a timely diagnosis. With appropriate management, IRS usually does not alter long-term prognosis.

The coming problem of HIV-associated Alzheimer's disease

BACKGROUND

Dementia associated with human immunodeficiency virus (HIV) is a subcortical neuropathology that does not resemble Alzheimer's disease. However, several lines of evidence suggest that in the future there may be significant numbers of long-term HIV survivors with true Alzheimer's disease. Age is itself a risk factor Alzheimer's disease, and an aging population and widespread use of highly active antiretroviral therapy (HAART) means more elderly HIV patients. Immune reconstitution inflammatory syndrome, lypodystrophic effects of HAART medications, HIV-induced amyloid deposition and excitotoxic effects of gp120 and TAT protein all could be risk factors for subsequent Alzheimer's disease. Finally, HIV patients will have greater vulnerability to common non-HIV pathogens that may contribute to development of Alzheimer's disease.

PRESENTATION OF THE HYPOTHESIS

It is predicted that in the future there will be seen measurable numbers of long-term HIV survivors on HAART who have Alzheimer's disease, with a cortical deficit profile on neuropsychological tests, pronounced cerebral atrophy seen on brain MRI, and neurofibrillary tangles, senile plaques and neuronal loss in post-mortem brain tissue. VALIDATING THE HYPOTHESIS: The hypothesis could be validated through case reports, longitudinal clinical studies, brain bank programs and animal models.

IMPLICATIONS OF THE HYPOTHESIS

Management of HIV may become more difficult, requiring greater provisions for long-term care of HIV patients with chronic dementia. However, it may be possible to reduce or prevent HIV-associated Alzheimer's disease through early use of cholinesterase inhibitors, glutamate-blocking drugs, insulin sensitizing agents, statins and anti-oxidants.

Dermatologic adverse effects of antiretroviral therapy: recognition and management

Despite the decrease in opportunistic infections associated with HIV in the highly active antiretroviral treatment (HAART) era, a significant number of patients still present with skin pathology, some of which can be attributed directly or indirectly to antiretroviral therapy. The non-nucleoside reverse transcriptase inhibitors exhibit a class effect with regard to skin adverse manifestations, and the spectrum of disease can vary from a mild morbilliform rash to Stevens-Johnson syndrome. Certain protease inhibitors are associated with rash, and indinavir causes retinoid-like manifestations such as paronychia, alopecia, ingrown toe-nails, and curling of straight hair. Abacavir, a nucleoside reverse transcriptase inhibitor, is notorious for causing a hypersensitivity reaction in select patients. The fusion inhibitor enfuvirtide causes injection-site reactions in the overwhelming majority of patients, although a new method of delivery has decreased the rate and severity of these reactions. A syndrome of lipoatrophy with or without lipohypertrophy, often termed lipodystrophy, has been described in patients receiving HAART. Potential management of lipoatrophy includes switching antiretrovirals and surgical treatment with facial fillers. Lastly, skin manifestations of the immune reconstitution inflammatory syndrome, including herpes zoster and warts, must be recognized and treated accordingly. In the evaluation of the individual HIV-infected patient receiving antiretroviral therapy who presents with a skin disorder, clinicians should consider the CD4 cell count as a marker of the degree of immunodeficiency, the specific antiretrovirals used, and the timing of the initiation of antiretroviral therapy in order to formulate a rational differential diagnosis. Management should be individualized based on the specific drug that is implicated and the severity of the reaction.

Therapy Insight: CNS manifestations of HIV-associated immune reconstitution inflammatory syndrome

The introduction of combination antiretroviral therapy for HIV infection has prolonged the lives of patients with AIDS. It is increasingly being recognized, however, that following initiation of this therapy some patients can develop a paradoxical neurological deterioration, despite dramatic improvements in HIV viral load and CD4+ T-cell counts. This immune reconstitution inflammatory syndrome (IRIS) in the CNS is emerging as an important neurological complication, particularly as antiretroviral therapy is now becoming readily available worldwide. Currently, there are no guidelines for prevention, diagnosis or treatment of the CNS manifestations of IRIS. Even in patients with an acute presentation, the diagnosis can be challenging. Furthermore, it is possible that more-chronic forms of the syndrome exist but remain unrecognized. Here, we review the various clinical presentations of CNS IRIS, and discuss options for their management.

Influence of highly active antiretroviral therapy on persistence of HIV in the central nervous system

PURPOSE OF REVIEW

The epidemiology of HIV infection is changing rapidly in the era of highly actively antiretroviral therapy, as the use of such therapy is increasing in all countries. This has had a significant impact on the neurological manifestations of HIV infection, posing new challenges in diagnosis and treatment. This review provides a critical analysis of the recent literature on the impact of highly actively antiretroviral therapy on HIV-related neurological complications and changes in treatment strategies.

RECENT FINDINGS

It is becoming clear that the brain is an important reservoir for the virus, and neuroinflammatory and neurodegenerative changes may continue despite the adequate use of highly actively antiretroviral therapy. Although this antiretroviral therapy has had a significant impact on the severity of HIV dementia, cognitive impairment persists. With improvement in the immune status following treatment with antiretrovirals, in rare cases the brain can become a target of the immune reconstitution.

SUMMARY

Highly actively antiretroviral therapy may need to be optimized in patients with HIV-associated cognitive impairment to achieve maximal central nervous system penetration; however, this therapeutic strategy may not be sufficient for halting the process. In some instances, the antiretroviral drugs themselves may become the problem. New strategies for neuroprotection that also target host genes which control HIV replication are being developed.