Multiple cerebral cryptococcomas associated with immune reconstitution in HIV-1 infection

Analysis of intracranial lesions in patients with HIV-associated cryptococcal meningitis

Background

Intracranial imaging abnormalities are commonly observed in patients suffering from HIV-associated cryptococcal meningitis, both before and during the treatment period. This study aims to analyze the prevalence, origins, radiological characteristics, treatments, and prognosis of intracranial lesions in patients with HIV-associated cryptococcal meningitis, thereby providing references for future clinical decision-making.

Methods

The clinical data of patients diagnosed with HIV-associated cryptococcal meningitis and admitted to the Shanghai Public Health Clinical Centre between 2013 and 2019 were collected. Logistic regression analysis was subsequently conducted to identify potential risk factors associated with the development of intracranial lesions in this patient group.

Results

Of 211 patients analyzed, 64.5% (136/211) had intracranial lesions during treatment and follow-up. Initial cranial imaging showed 60% had lesions pre-treatment. Throughout treatment, 32.7% (52/159) developed new or worsened lesions. Mortality rates at 2 weeks, 8 weeks, and 2 years for those with detected lesions were 3%, 7.6%, and 13.2%, respectively. Lesions were primarily caused by Cryptococcus (70.5%) and Mycobacterium (24.3%). Lacunar infarcts, especially in the basal ganglia, were the most common type. Patients aged 50 years or older, and those presenting with altered mental status upon admission, were found to be more likely to have intracranial lesions at baseline, with adjusted odds ratios of 5.364 (95% CI: 1.468-19.591, P=0.011) and 7.970 (95% CI: 2.241-28.337, P=0.001), respectively. Patients with lesion progression showed higher levels of IFN-γ, IL-4, IL-5, IL-6, IL-1Ra, IL-1β, GM-CSF, Eotaxin, and Basic FGF in cerebrospinal fluid after four weeks of treatment.

Conclusion

Intracranial lesions in HIV-associated cryptococcal meningitis patients are mostly due to Cryptococcus and Mycobacterium infections. They often appear as lacunar infarcts, predominantly in the basal ganglia, and can worsen with treatment initiation, possibly due to higher baseline cytokine levels in cerebrospinal fluid.

Cryptococcal meningitis: a review for emergency clinicians

INTRODUCTION

Cryptococcal Meningitis (CM) remains a high-risk clinical condition, and many patients require emergency department (ED) management for complications and stabilization.

OBJECTIVE

This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of CM.

DISCUSSION

This review evaluates the diagnosis, management, and empiric treatment of suspected CM in the ED. CM can easily evade diagnosis with a subacute presentation, and should be considered in any patient with a headache, neurological deficit, or who is immunocompromised. As a definitive diagnosis of CM will not be made in the ED, management of a patient with suspected CM includes prompt diagnostic testing and initiation of empiric treatment. Multiple types of newer Cryptococcal antigen tests provide high sensitivity and specificity both in serum and cerebrospinal fluid (CSF). Patients should be treated empirically for bacterial, fungal, and viral meningitis, specifically with amphotericin B and flucytosine for presumed CM. Additionally, appropriate resuscitation and supportive care, including advanced airway management, management of increased intracranial pressure (ICP), antipyretics, intravenous fluids, and isolation, should be initiated. Antiretroviral therapy (ART) should not be initiated in the ED for those found or known to be HIV-positive for risk of immune reconstitution inflammatory syndrome (IRIS).

CONCLUSIONS

CM remains a rare clinical presentation, but carries significant morbidity and mortality. Physicians must rapidly diagnose these patients while evaluating for other diseases and complications. Early consultation with an infectious disease specialist is imperative, as is initiating symptomatic care.

Subtle Cryptococcal Immune Reconstitution Inflammatory Syndrome

Patients with HIV and opportunistic infections (OIs), such as tuberculosis and cryptococcosis, have been recognised to have immune reconstitution inflammatory syndrome (IRIS) following initiation of highly active antiretroviral therapy (HAART). The initiation of HAART boosts CD4 T cells, which result in exacerbations of OIs. We have identified deterioration of neural lesion in imaging after the initiation of HAART in a patient with HIV/cryptococcal infection, although patient's clinical conditions have not deteriorated. It is evident that IRIS is in subtlety. This has been possible because of prompt treatment with antifungal drugs for the cryptococcal infection, followed by early initiation of HAART.

Monocyte Phenotype and IFN-γ-Inducible Cytokine Responses Are Associated with Cryptococcal Immune Reconstitution Inflammatory Syndrome

A third of adults with AIDS and cryptococcal meningitis (CM) develop immune reconstitution inflammatory syndrome (IRIS) after initiating antiretroviral therapy (ART), which is thought to result from exaggerated inflammatory antigen-specific T cell responses. The contribution of monocytes to the immunopathogenesis of cryptococcal IRIS remains unclear. We compared monocyte subset frequencies and immune responses in HIV-infected Ugandans at time of CM diagnosis (IRIS-Baseline) for those who later developed CM-IRIS, controls who did not develop CM-IRIS (Control-Baseline) at CM-IRIS (IRIS-Event), and for controls at a time point matched for ART duration (Control-Event) to understand the association of monocyte distribution and immune responses with cryptococcal IRIS. At baseline, stimulation with IFN-γ ex vivo induced a higher frequency of TNF-α- and IL-6-producing monocytes among those who later developed IRIS. Among participants who developed IRIS, ex vivo IFN-γ stimulation induced higher frequencies of activated monocytes, IL-6⁺, TNF-α⁺ classical, and IL-6⁺ intermediate monocytes compared with controls. In conclusion, we have demonstrated that monocyte subset phenotype and cytokine responses prior to ART are associated with and may be predictive of CM-IRIS. Larger studies to further delineate innate immunological responses and the efficacy of immunomodulatory therapies during cryptococcal IRIS are warranted.

The immunopathogenesis of cryptococcal immune reconstitution inflammatory syndrome: understanding a conundrum

PURPOSE OF REVIEW

Cryptococcal meningitis causes significant mortality among HIV-infected patients, despite antifungal therapy and use of antiretroviral therapy (ART). In patients with cryptococcal meningitis, ART is often complicated by immune reconstitution inflammatory syndrome (IRIS), manifesting as unmasking of previously unrecognized subclinical infection (unmasking CM-IRIS) or paradoxical worsening of symptoms in the central nervous system after prior improvement with antifungal therapy (paradoxical CM-IRIS). We review our current understanding of the pathogenesis of this phenomenon, focusing on unifying innate and adaptive immune mechanisms leading to the development of this often fatal syndrome.

RECENT FINDINGS

We propose that HIV-associated CD4 T-cell depletion, chemokine-driven trafficking of monocytes into cerebrospinal fluid in response to cryptococcal meningitis, and poor localized innate cytokine responses lead to inadequate cryptococcal killing and clearance of the fungus. Subsequent ART-associated recovery of T-cell signaling and restored cytokine responses, characterized by IFN-γ production, triggers an inflammatory response. The inflammatory response triggered by ART is dysregulated because of impaired homeostatic and regulatory mechanisms, culminating in the development of CM-IRIS.

SUMMARY

Despite our incomplete understanding of the immunopathogenesis of CM-IRIS, emerging data exploring innate and adaptive immune responses could be exploited to predict, prevent and manage CM-IRIS and associated morbid consequences.

A Retrospective Cohort Study of Lesion Distribution of HIV-1 Infection Patients With Cryptococcal Meningoencephalitis on MRI: Correlation With Immunity and Immune Reconstitution

The objective of this paper is to correlate the MRI distribution of cryptococcal meningoencephalitis in HIV-1 infection patients with CD4 T cell count and immune reconstitution effect.A large retrospective cohort study of HIV patients from multi-HIV centers in China was studied to demonstrate the MRI distribution of cryptococcal meningoencephalitis and its correlation with the different immune status.The consecutive clinical and neuroimaging data of 55 HIV-1-infected patients with cryptococcal meningoencephalitis collected at multi-HIV centers in China during the years of 2011 to 2014 was retrospectively analyzed. The enrolled patients were divided into 2 groups based on the distribution of lesions. One group of patients had their lesions at the central brain (group 1, n = 34) and the other group of patients had their lesions at the superficial brain (group 2, n = 21). We explored their MRI characterization of brain. In addition, we also compared their CD4 T cell counts and immune reconstitution effects between the 2 groups based on the imaging findings.No statistical difference was found in terms of age and gender between the 2 groups. The medians of CD4 T cell counts were 11.67 cells/mm (3.00-52.00 cells/mm) in group 1 and 42.00 cells/mm (10.00-252.00 cells/mm) in group 2. Statistical difference of CD4 T cell count was found between the 2 groups (P = 0.023). Thirteen patients in group 1 (13/34) and 12 patients in group 2 (12/21) received highly active antiretroviral treatment (HAART). Patients of group 2 received HAART therapy more frequently than patients of group 1 (P = 0.021).Central and superficial brain lesions detected by MR imaging in HIV-1-infected patients with cryptococcal meningoencephalitis are in correlation with the host immunity and HAART therapy.

Spectrum of imaging appearances of intracranial cryptococcal infection in HIV/AIDS patients in the anti-retroviral therapy era

Cryptococcus neoformans infection is the most common fungal infection of the central nervous system (CNS) in advanced human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) patients, but remains a relatively uncommon CNS infection in both the immunocompromised and immunocompetent patient population, rendering it a somewhat elusive and frequently overlooked diagnosis. The morbidity and mortality associated with CNS cryptococcal infection can be significantly reduced by early recognition of the imaging appearances by the radiologist in order to focus and expedite clinical management and treatment. The emergence and evolution of anti-retroviral therapy have also impacted significantly on the imaging appearances, morbidity, and mortality of this neuro-infection. The constellation of varied imaging appearances associated with cryptococcal CNS infection in the HIV and AIDS population in the era of highly active anti-retroviral therapy (HAART) will be presented in this review.

A paradoxical decline: intracranial lesions in two HIV-positive patients recovering from cryptococcal meningitis

Cryptococcal immune reconstitution inflammatory syndrome (C-IRIS) is an increasingly important manifestation among patients with HIV/AIDS, especially as the use of antiretroviral therapy (ART) is expanding worldwide. Cryptococcus and associated C-IRIS are common causes of meningitis. While intracranial lesions are common in HIV/AIDS, they are rarely due to cryptococcosis or C-IRIS. We describe two cases of paradoxical C-IRIS associated with the development of intracranial cryptococcomas in HIV/AIDS. Both patients had an initial episode of cryptococcal meningitis treated with antifungal therapy. At the time, they had initiated or modified ART with subsequent evidence of immune reconstitution. Two months later, they developed aseptic meningitis with intracranial lesions. After exhaustive work ups, both patients were diagnosed with paradoxical C-IRIS and biopsy confirmed intracranial cryptococcomas. We review the important clinical, diagnostic and therapeutic features of cryptococcomas associated with C-IRIS in HIV/AIDS.

Diagnostic Performance of Brain MRI in Immune Reconstitution Inflammatory Syndrome

BACKGROUND AND PURPOSE

Central nervous system immune reconstitution inflammatory syndrome (CNS-IRIS) significantly negatively impacts the human immunodeficiency virus (HIV)-infected population on combination antiretroviral therapy (cART). We sought to determine the diagnostic performance of several magnetic resonance imaging (MRI) features for CNS-IRIS in a cohort of HIV+ patients recently started on cART.

METHODS

Our radiologic database was searched from January 2003 to September 2014 retrospectively for patients diagnosed with HIV and worsening symptoms on cART. A total of 20 patients with HIV were identified; patients were classified as having CNS-IRIS on the basis of established clinical criteria (8 patients; 12 age- and sex-matched controls). Brain MR images were obtained at a single post-cART timepoint during hospitalization for acute neurologic deterioration and blindly interpreted by two experienced neuroradiologists for the presence of four variables: intrinsic T1 hyperintensity, marginal reduced diffusion, and marginal enhancement or perivascular enhancement.

RESULTS

Although each individual finding showed moderate predictive accuracy, the combination of MR findings demonstrated good test characteristics: sensitivity 88% (confidence interval [CI] 62-98), specificity 79% (58-93), positive predictive value 71% (44-90%), and negative predictive value 83% (CI 52-98%). In addition, this final diagnosis demonstrated good predictive accuracy, area under curve .78 (CI .63-.91), and moderate inter-reader agreement, κ = .55.

CONCLUSIONS

Our findings suggest that although each individual MR finding shows only moderate diagnostic performance, the combined assessment of experienced neuroradiologists has good predictive accuracy. The absence of any described MRI findings makes the diagnosis of CNS-IRIS highly unlikely.

Neuroimaging of HIV-associated cryptococcal meningitis: comparison of magnetic resonance imaging findings in patients with and without immune reconstitution

To determine the frequency, imaging characteristics, neuroanatomical distribution and dynamics of magnetic resonance imaging findings in HIV-associated cryptococcal meningitis in immunocompromised patients we compared patients without antiretroviral therapy with patients undergoing immune reconstitution. Neuroimaging and clinical data of 21 consecutive patients presenting to a German HIV centre in a 10-year period between 2005 and 2014 were reviewed. We identified eight patients with magnetic resonance imaging findings related to cryptococcal disease: five patients without antiretroviral therapy and three patients receiving effective antiretroviral therapy resulting in immune reconstitution. The pattern of magnetic resonance imaging manifestations was different in the two groups. In patients not on antiretroviral therapy, pseudocysts (n = 3) and lacunar ischaemic lesions (n = 2) were detected. Contrast-enhancing focal leptomeningeal and/or parenchymal lesions were found in all patients under immune reconstitution (n = 3). Magnetic resonance imaging lesions suggestive of leptomeningitis or meningoencephalitis were detected in all patients with a recurrence of cryptococcal meningitis under immune reconstitution, which differs from the classical magnetic resonance imaging findings in patients without antiretroviral therapy. In antiretroviral therapy-treated patients with past medical history of cryptococcal meningitis, detection of contrast-enhancing focal meningeal and/or parenchymal lesions should prompt further investigations for a recurrence of cryptococcal meningitis under immune reconstitution.

Cellular immune activation in cerebrospinal fluid from ugandans with cryptococcal meningitis and immune reconstitution inflammatory syndrome

Background. Human immunodeficiency virus (HIV)-associated cryptococcal meningitis (CM) is characterized by high fungal burden and limited leukocyte trafficking to cerebrospinal fluid (CSF). The immunopathogenesis of CM immune reconstitution inflammatory syndrome (IRIS) after initiation of antiretroviral therapy at the site of infection is poorly understood.

Methods. We characterized the lineage and activation status of mononuclear cells in blood and CSF of HIV-infected patients with noncryptococcal meningitis (NCM) (n = 10), those with CM at day 0 (n = 40) or day 14 (n = 21) of antifungal therapy, and those with CM-IRIS (n = 10).

Results. At diagnosis, highly activated CD8⁺ T cells predominated in CSF in both CM and NCM. CM-IRIS was associated with an increasing frequency of CSF CD4⁺ T cells (increased from 2.2% to 23%; P = .06), a shift in monocyte phenotype from classic to an intermediate/proinflammatory, and increased programmed death ligand 1 expression on natural killer cells (increased from 11.9% to 61.6%, P = .03). CSF cellular responses were distinct from responses in peripheral blood.

Conclusions. After CM, T cells in CSF tend to evolve with the development of IRIS, with increasing proportions of activated CD4⁺ T cells, migration of intermediate monocytes to the CSF, and declining fungal burden. These changes provide insight into IRIS pathogenesis and could be exploited to more effectively treat CM and prevent CM-IRIS.

New Insights into HIV/AIDS-Associated Cryptococcosis

Cryptococcal meningitis is a life-threatening opportunistic fungal infection in both HIV-infected and HIV-uninfected patients. According to the most recent taxonomy, the responsible fungus is classified into a complex that contains two species (Cryptococcus neoformans and C. gattii), with eight major molecular types. HIV infection is recognized worldwide as the main underlying disease responsible for the development of cryptococcal meningitis (accounting for 80-90% of cases). In several areas of sub-Saharan Africa with the highest HIV prevalence despite the recent expansion of antiretroviral (ARV) therapy programme, cryptococcal meningitis is the leading cause of community-acquired meningitis with a high mortality burden. Although cryptococcal meningitis should be considered a neglected disease, a large body of knowledge has been developed by several studies performed in recent years. This paper will focus especially on new clinical aspects such as immune reconstitution inflammatory syndrome, advances on management, and strategies for the prevention of clinical disease.

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.

Challenges in diagnosis and management of Cryptococcal immune reconstitution inflammatory syndrome (IRIS) in resource limited settings

In many resource-limited settings, cryptococcal meningitis (CM) contributes up to 20% of all deaths with further complications due to Immune Reconstitution Inflammatory Syndrome (IRIS). We present a case report on a patient who developed CM-IRIS and then subsequent CM-relapse with a fluconazole-resistant organism and then later CM-IRIS once again, manifesting as cystic cryptococcomas, hydrocephalus, and sterile CSF. In this case we, demonstrate that CM-IRIS and persistent low level cryptococcal infection are not mutually exclusive phenomena. The management of IRIS with corticosteroids may increase the risk of culture positive CM-relapse which may further increase the risk of recurrent IRIS and resulting complications including death. We also highlight the role of imaging and fluconazole resistance testing in patients with recurrent meningitis and the importance of CSF cultures in guiding treatment decisions.

Central nervous system immune reconstitution inflammatory syndrome in AIDS: experience of a Mexican neurological centre

BACKGROUND

Highly active antiretroviral therapy (HAART) restores the inflammatory immune response in AIDS patients and it may unmask previous subclinical infections or paradoxically exacerbate symptoms of opportunistic infections. Up to 25% of patients receiving HAART develop immune reconstitution inflammatory syndrome (IRIS). We describe six patients with IRIS central nervous system (CNSIRIS) manifestations emphasizing the relevance of CSF cultures and neuroimaging in early diagnosis and management.

METHODS

Patients with CNSIRIS were identified among hospitalized HIV-infected patients that started HAART from January 2002 through December 2007 at a referral neurological center in Mexico.

RESULTS

One-hundred and forty-two HIV-infected patients with neurological signs were hospitalized, 64 of which had received HAART, and six (9.3%) developed CNSIRIS. Five patients were male. Two cases of tuberculosis, two of cryptococcosis, one of brain toxoplasmosis, and one possible PML case were found. IRIS onset occurred within 12 weeks of HAART in five patients. Anti-infective therapy was continued. In one case, HAART was temporarily suspended. In long-term follow-up the clinical condition improved in all patients.

CONCLUSIONS

CNSIRIS associated to opportunistic infections appeared in 9% of patients receiving HAART. Interestingly, no cases of malignancy or neoplasm IRIS-related were found. Frequent clinical assessment and neuroimaging studies supported diagnosis and treatment. Risk factors were similar to those found in other series.

Cryptococcal immune reconstitution inflammatory syndrome in HIV-1-infected individuals: proposed clinical case definitions

Cryptococcal immune reconstitution inflammatory syndrome (IRIS) may present as a clinical worsening or new presentation of cryptococcal disease after initiation of antiretroviral therapy (ART), and is thought to be caused by recovery of cryptococcus-specific immune responses. We have reviewed reports of cryptococcal IRIS and have developed a consensus case definition specifically for paradoxical crytopcoccal IRIS in patients with HIV-1 and known cryptococcal disease before ART, and a separate definition for incident cryptococcosis developed during ART (termed ART-associated cryptococcosis), for which a proportion of cases are likely to be unmasking cryptococcal IRIS. These structured case definitions are intended to aid design of future clinical, epidemiological, and immunopathological studies of cryptococcal IRIS, to standardise diagnostic criteria, and to facilitate comparisons between studies. As for definitions of tuberculosis-associated IRIS, definitions for cryptococcal IRIS should be regarded as preliminary until further insights into the immunopathology of IRIS permit their refinement.

Pediatric renal cryptococcosis: novel manifestations in the acquired immunodeficiency syndrome era

Pediatric cryptococcosis has been documented in various organs, but pediatric renal cryptococcosis (RC) remains undocumented to date. The authors report RC in 2 children with AIDS, 7 and 9 years of age, with proteinuria. Both patients, on antiretroviral therapy (ARV) for 28 (patient 1) and 54 (patient 2) weeks each, had secured viral immunosuppression, but immune restoration was realized by patient 1 only. Cryptococcal immune reconstitution inflammatory syndrome (IRIS) was diagnosed on the renal biopsy from patient 1 based on the clinicopathological profile and the presence of segmental glomerular and an interstitial lymphoplasmacytic and granulomatous reaction to Cryptococcus neoformans, with a predominance of capsule-deficient fungal forms. The renal biopsy from patient 2 demonstrated typical HIV-associated nephropathy with focal intratubular and interstitial C neoformans yeasts. Pediatric AIDS-associated renal disease must be expanded to include RC and cryptococcal IRIS, and the kidney must be included as a potential sentinel site of IRIS.

A proteomic-based approach for the identification of immunodominant Cryptococcus neoformans proteins

Cryptococcus neoformans is an opportunistic fungal pathogen that can cause life-threatening meningoencephalitis in immune compromised patients. Previous, studies in our laboratory have shown that prior exposure to an IFN-gamma-producing C. neoformans strain (H99gamma) elicits protective immunity against a second pulmonary C. neoformans challenge. Here, we characterized the antibody response produced in mice protected against experimental pulmonary C. neoformans infection compared to nonprotected mice. Moreover, we evaluated the efficacy of using serum antibody from protected mice to detect immunodominant C. neoformans proteins. Protected mice were shown to produce significantly more C. neoformans-specific antibodies following a second experimental pulmonary cryptococcal challenge compared to nonprotected mice. Immunoblot analysis of C. neoformans proteins resolved by 2-DE using serum from nonprotected mice failed to show any reactivity. In contrast, serum from protected mice was reactive with several cryptococcal protein spots. Analysis of these spots by capillary HPLC-ESI-MS/MS identified several cryptococcal proteins shown to be associated with the pathogenesis of cryptococcosis. Our studies demonstrate that mice immunized with C. neoformans strain H99gamma produce antibodies that are immune reactive against specific cryptococcal proteins that may provide a basis for the development of immune based therapies that induce protective anticryptococcal immune responses.

Immune reconstitution inflammatory syndrome producing atypical presentations of cryptococcal meningitis: Case report and a review of immune reconstitution-associated cryptococcal infections

Atypical presentations of cryptococcal infection have been described as manifestations of immune reconstitution in HIV-infected patients following introduction of antiretroviral therapy. We describe a patient presenting with cryptococcal meningitis as an immune reconstitution reaction 10 weeks after initiation of anti-retroviral therapy. Subclinical CSF cryptococcal infection was demonstrated and the serum cryptococcal antigen was negative.

Immune reconstitution inflammatory syndrome in HIV-associated cryptococcal meningitis: a prospective study

BACKGROUND

Prospective data on incidence, characteristics, and risk factors for cryptococcal meningitis immune reconstitution inflammatory syndrome (CM-IRIS) are lacking.

METHODS

Prospective study of 65 antiretroviral therapy (ART)-naive HIV-infected cryptococcal meningitis (CM) patients, who started ART after initiation of antifungal treatment. CM-IRIS definition: (1) cerebrospinal fluid (CSF) culture-confirmed CM, (2) symptom resolution before starting ART, (3) adherence to fluconazole and ART, (4) recurrence of CM symptoms after starting ART, (5) immunologic and/or virologic response to ART, (6) no alternative diagnosis.

RESULTS

ART was started at a median of 47 days from CM diagnosis. CM-IRIS developed in 11 of 65 (17%), at a median 29 days from starting ART. No factors at first CM episode (fungal burden, rate of clearance, CSF, or HIV parameters) predicted those at risk of CM-IRIS. At 6 months on ART, IRIS patients had greater CD4 rise from baseline (220 vs. 124 x 10 cells /L in non-IRIS, P = 0.01), and 4 of 11 CM-IRIS patients died compared with 14 of 54 non-IRIS patients (P = 0.5). For those developing CM-IRIS, CSF proinflammatory cytokines interferon gamma, tumour necrosis factor alpha, and interleukin 6, did not differ between first CM and CM-IRIS episode.

CONCLUSIONS

Patients with CM-IRIS had greater immune restoration in response to ART. Although common and potentially fatal, larger prospective studies are needed to determine whether CM-IRIS, in patients treated initially with amphotericin B, is associated with any increase in overall mortality.

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.

Immune reconstitution inflammatory syndrome in HIV-infected patients receiving antiretroviral therapy : pathogenesis, clinical manifestations and management

The use of antiretroviral therapy (ART) to treat HIV infection, by restoring CD4+ cell count and immune function, is associated with significant reductions in morbidity and mortality. Soon after ART initiation, there is a rapid phase of restoration of pathogen-specific immunity. In certain patients, this results in inflammatory responses that may result in clinical deterioration known as 'the immune reconstitution inflammatory syndrome' (IRIS). IRIS may be targeted at viable infective antigens, dead or dying infective antigens, host antigens, tumour antigens and other antigens, giving rise to a heterogeneous range of clinical manifestations. The commonest forms of IRIS are associated with mycobacterial infections, fungi and herpes viruses. In most patients, ART should be continued and treatment for the associated condition optimized, and there is anecdotal evidence for the use of corticosteroids in patients who are severely affected. In this review, we discuss research relating to pathogenesis, the range of clinical manifestations, treatment options and prevention issues.

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.

Cryptococcosis

In the past 2 decades, Cryptococcus has emerged in its clinical significance and as a model yeast for understanding molecular pathogenesis. C neoformans and C gattii are currently considered major primary and secondary pathogens in a wide array of hosts that are known to be immunocompromised or apparently immunocompetent. A recent outbreak of C gattii infections further underscores the clinical importance of the yeast through its epidemiology and pathogenicity features. With an enlarging immunosuppressed population caused by HIV infection, solid organ transplantation, and clinical use of potent immunosuppressives, such as cancer chemotherapy, monoclonal antibodies, and corticosteroids, this fungus has become a well-established infectious complication of modern medicine. This article examines current issues in cryptococcal infections, including new classification, epidemiology, pathogenesis, and specific clinical aspects.

Cryptococcal immune reconstitution inflammatory syndrome: report of four cases in three patients and review of the literature

Immune reconstitution inflammatory syndromes (IRIS) in patients with AIDS are characterized by atypical manifestations of opportunistic pathogens in patients experiencing improvement in CD4 cell counts following receipt of highly active anti-retroviral therapy (HAART). We report four cases of IRIS due to Cryptococcus neoformans in three patients and review the literature of cryptococcal IRIS in AIDS (an additional 21 episodes). The IRIS presentation was lymphadenitis in all three patients; one patient also had meningeal IRIS. Combining our patients with the literature review revealed the following IRIS presentations: lymphadenitis (n=14), central nervous system (CNS) IRIS (n=10): meningitis in six and mass lesions in four, and pulmonary cavities (n=1). The median CD4 count of cases at the time of initial cryptococcal diagnosis and prior to the start of HAART was 25 cells/microl and the median HIV viral load was 439,053 copies/ml. At time of presentation of the IRIS, the median CD4 count had increased by 197 cells/microl. The median time from initial cryptococcal diagnosis and the start of HAART to the IRIS was 11 months (range 7 weeks to 3 years) and 7 months (range <2 weeks to 22 months), respectively. Patients with CNS IRIS tended to have shorter intervals from initiation of HAART to presentation compared to patients with lymphadenitis: median 3.5 months compared to 7 months. In 24 of 25 cases, the clinical manifestations of the IRIS resolved (range: days to months). Only four patients were given anti-inflammatory medications: corticosteroids in two and non-steroidal anti-inflammatory drugs in two, thus precluding assessment of efficacy. Patients with cryptococcal disease who initiate HAART are at risk for cryptococcal IRIS.

The poor prognosis of central nervous system cryptococcosis among nonimmunosuppressed patients: a call for better disease recognition and evaluation of adjuncts to antifungal therapy

We describe 9 nonimmunosuppressed patients with central nervous system cryptococcosis. Morbidity and mortality were high, especially among patients with cerebral infarcts. This was attributed to delayed diagnosis and apparent sequelae of overwhelming host immune responses. We present clues suggesting the diagnosis. Increased recognition and timely diagnosis of this condition may improve outcomes.

Incidence and risk factors of immune reconstitution inflammatory syndrome complicating HIV-associated cryptococcosis in France

BACKGROUND

Immune reconstitution inflammatory syndrome (IRIS) in association with cryptococcosis has been anecdotically reported following administration of highly active antiretroviral therapy (HAART).

OBJECTIVE

To analyse the incidence and risk factors for IRIS-associated cryptococcosis among HIV-infected patients.

DESIGN

Retrospective multicentre study between 1996 and 2000 through the French Cryptococcosis Database.

METHODS

Subsequent occurrence of IRIS examined in 120 HIV-infected adult patients treated with HAART and experiencing a first episode of culture-confirmed cryptococcosis.

RESULTS

Ten patients developed IRIS during the study period, giving an incidence of 10/239, or 4.2/100 person-years [95% confidence interval (CI), 2.2-7.8]. IRIS consisted of acute symptoms consistent with inflammation occurring within a median of 8 months (range, 2-37) after the diagnosis of cryptococcosis in the context of negative cultures and immunological and/or virological response to HAART. Radiology and histopathology detected features compatible with inflammation. Symptom severity required transfer into intensive care units for three patients and use of anti-inflammatory drugs for four. Three patients with evolutive IRIS died. Compared with patients without IRIS for whom complete clinical and microbiological information were available at baseline, previously unknown HIV infection [odds ratio (OR), 4.8; 95% CI, 1.0-21.7], CD4 cell count < 7 x 10 cells/l (OR, 4.0; 95% CI, 0.9-17.2), fungaemia (OR, 6.1; 95% CI, 1.1-35.2) and HAART initiation within 2 months of cryptococcosis diagnosis (OR, 5.50; 95% CI, 1.0-29.6) were independently associated with the risk of subsequent IRIS.

CONCLUSIONS

IRIS-related cryptococcosis was observed more frequently in severely immunocompromised patients with disseminated infection and HAART initiation soon after the diagnosis.

An Immune Reconstitution Syndrome-Like Illness Associated withCryptococcus neoformans Infection in Organ Transplant Recipients

BACKGROUND

We describe an immune reconstitution syndrome (IRS)-like entity in the course of evolution of Cryptococcus neoformans infection in organ transplant recipients.

METHODS

The study population comprised a cohort of 83 consecutive organ transplant recipients with cryptococcosis who were observed for a median of 2 years in an international, multicenter study.

RESULTS

In 4 (4.8%) of the 83 patients, an IRS-like entity was observed a median of 5.5 weeks after the initiation of appropriate antifungal therapy. Worsening of clinical manifestations was documented, despite cultures being negative for C. neoformans. These patients were significantly more likely to have received tacrolimus, mycophenolate mofetil, and prednisone as the regimen of immunosuppressive therapy than were all other patients (P = .007). The proposed basis of this phenomenon is reversal of a predominantly Th2 response at the onset of infection to a Th1 proinflammatory response as a result of receipt of effective antifungal therapy and a reduction in or cessation of immunosuppressive therapy.

CONCLUSIONS

This study demonstrated that an IRS-like entity occurs in organ transplant recipients with C. neoformans infection. Furthermore, this entity may be misconstrued as a failure of therapy. Immunomodulatory agents may have a role as adjunctive therapy in such cases.

The Role of Immune Reconstitution Inflammatory Syndrome in AIDS‐RelatedCryptococcus neoformansDisease in the Era of Highly Active Antiretroviral Therapy

This study of human immunodeficiency virus (HIV)-infected patients coinfected with Cryptococcus neoformans found that 30% of patients who initiated highly active antiretroviral therapy developed immune reconstitution inflammatory syndrome (IRIS). Patients with C. neoformans-related IRIS had higher cerebrospinal fluid opening pressures, glucose levels, and white blood cell counts, compared with patients with typical HIV-associated C. neoformans meningitis.

Illness of immune reconstitution: Recognition and management

Some individuals who initiate highly active antiretroviral therapy (HAART) develop new or worsening opportunistic infections or malignancies despite improvements in surrogate markers of HIV-1 infection. These events of paradoxical clinical worsening, also known as immune reconstitution syndromes (IRS), are increased in individuals with prior opportunistic infections or low CD4+ T-cell nadirs. They are thought to result from reconstitution of the immune system's ability to recognize pathogens or tumor antigens that were previously present, but clinically asymptomatic. There is no consensus regarding the diagnostic criteria or pathogenesis of IRS. Knowledge of their presentation and treatment is largely based on case reports. With the introduction of HAART into resource-limited settings, it is likely that significantly more and distinct forms of IRS will be observed. Prospective studies of the incidence and treatment of IRS in multiple settings are critical to better understand their pathogenesis and optimal management.