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

The impact of the host on fungal infections

Outcomes of fungal infections in immunocompromised individuals depend on a complex interplay between host and pathogen factors, as well as treatment modalities. Problems occur when host responses to an infection are either too weak to effectively help eradicate the pathogen, or when they become too strong and are associated with host damage rather than protection. Immune reconstitution syndrome (IRS) can be generally defined as a restoration of host immunity in a previously immunosuppressed patient that becomes dysregulated and overly robust, resulting in host damage and sometimes death. IRS associated with opportunistic mycoses presents as new or worsening clinical symptoms or radiographic signs consistent with an inflammatory process that occur during receipt of an appropriate antifungal, and that cannot be explained by a newly acquired infection. Because there are currently no established tests or biomarkers for IRS, it can be difficult to distinguish from progression of the original infection, although culture and biomarkers for the fungal pathogen or infection are typically negative during diagnostic workup. IRS was originally characterized in human immunodeficiency virus-infected patients receiving antiretroviral therapy, but has subsequently been described in solid-organ transplant recipients, neutropenic patients, women in the postpartum period, and recipients of tumor necrosis factor-α inhibitor therapy. In each of these cases, recovery of the host's immunity during treatment of an initial infection results in a powerful proinflammatory environment that overshoots and leads to host damage. Optimal management of IRS has not been established at present, but often involves treatment with a corticosteroid or other anti-inflammatory compounds. This article uses a number of patient cases to explore the intricacies of diagnosing and managing a patient with IRS, as well as the other extreme, namely patients who are so immunocompromised without immune recovery that they essentially become breeding grounds for a wide range of opportunistic pathogens, often simultaneously.

Opportunistic infection-associated immune reconstitution syndrome in transplant recipients

Reversal of pathogen-induced immunosuppression upon employment of effective antimicrobial therapy and withdrawal of iatrogenic immunosuppression has the potential to shift the host immune repertoire towards pathologic inflammatory responses conducive to immune reconstitution syndrome (IRS). Posttransplant IRS has been observed with fungi, M. tuberculosis, cytomegalovirus, and polyoma virus nephropathy. This review discusses the existing state of knowledge regarding IRS and the immune mechanisms that underlie its pathogenesis, with significant implications for developing reliable diagnostic biomarkers and optimal management strategies for post-transplant opportunistic infection-associated IRS.

Management of fungal lung disease in the immunocompromised

Pulmonary mycoses are among the most feared infections encountered in immunocompromised patients. The problem is amplified by the increasing numbers of chronically immunocompromised patients that have substantially increased both the prevalence and clinical severity of infections caused by fungi. Moreover, fungal infections in this patient population pose challenges in diagnosis and management. Fortunately, recent advances in diagnostics and antifungal therapy, and their direct application to specific diseases, provide important new approaches to this complex and often seriously ill patient population. In this article we review the commonly occurring pulmonary fungal infections in the immunocompromised population with a particular focus on their management.

Emerging fungal infections in immunocompromised patients

Invasive fungal infections are infections of importance and are increasing in incidence in immunocompromised hosts such as patients who have had hematopoietic stem cell and solid organ transplants. Despite our expanded antifungal armamentarium, these infections cause considerable morbidity and mortality. Indeed, certain trends have emerged in these invasive fungal infections: a rise in the incidence of invasive mold infections, an increase in the non-albicans strains of Candida spp. causing invasive disease and, finally, the emergence of less susceptible fungal strains that are resistant to the broader-spectrum antifungal agents due to overutilization of these agents. Clinicians must recognize the patient groups that are potentially at risk for these invasive fungal infections, as well as the risk factors for such infections. By using more sensitive nonculture-based diagnostic techniques, appropriate therapy may be initiated earlier to enhance survival in these immunocompromised patient populations.

[Guidelines for the treatment of Invasive Candidiasis and other yeasts. Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). 2010 Update]

These guidelines are an update of the recommendations of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) that were issued in 2004 (Enferm Infecc Microbiol Clin. 2004, 22:32-9) on the treatment of Invasive Candidiasis and infections produced by other yeasts. This 2010 update includes a comprehensive review of the new drugs that have appeared in recent years, as well as the levels of evidence for recommending them. These guidelines have been developed following the rules of the SEIMC by a working group composed of specialists in infectious diseases, clinical microbiology, critical care medicine, paediatrics and oncology-haematology. It provides a series of general recommendations regarding the management of invasive candidiasis and other yeast infections, as well as specific guidelines for prophylaxis and treatment, which have been divided into four sections: oncology-haematology, solid organ transplantation recipients, critical patients, and paediatric patients.

An official American Thoracic Society statement: Treatment of fungal infections in adult pulmonary and critical care patients

With increasing numbers of immune-compromised patients with malignancy, hematologic disease, and HIV, as well as those receiving immunosupressive drug regimens for the management of organ transplantation or autoimmune inflammatory conditions, the incidence of fungal infections has dramatically increased over recent years. Definitive diagnosis of pulmonary fungal infections has also been substantially assisted by the development of newer diagnostic methods and techniques, including the use of antigen detection, polymerase chain reaction, serologies, computed tomography and positron emission tomography scans, bronchoscopy, mediastinoscopy, and video-assisted thorascopic biopsy. At the same time, the introduction of new treatment modalities has significantly broadened options available to physicians who treat these conditions. While traditionally antifungal therapy was limited to the use of amphotericin B, flucytosine, and a handful of clinically available azole agents, current pharmacologic treatment options include potent new azole compounds with extended antifungal activity, lipid forms of amphotericin B, and newer antifungal drugs, including the echinocandins. In view of the changing treatment of pulmonary fungal infections, the American Thoracic Society convened a working group of experts in fungal infections to develop a concise clinical statement of current therapeutic options for those fungal infections of particular relevance to pulmonary and critical care practice. This document focuses on three primary areas of concern: the endemic mycoses, including histoplasmosis, sporotrichosis, blastomycosis, and coccidioidomycosis; fungal infections of special concern for immune-compromised and critically ill patients, including cryptococcosis, aspergillosis, candidiasis, and Pneumocystis pneumonia; and rare and emerging fungal infections.

Immune reconstitution inflammatory syndrome mimicking relapsing cryptococcal meningitis in a renal transplant recipient

Immune reconstitution inflammatory syndrome (IRIS) is a rare entity that has been described recently in solid organ transplant (SOT) recipients. IRIS is characterized by an exuberant and dysregulated immune response following treatment of opportunistic infections. We describe here the case of a kidney transplant recipient who developed cryptococcal meningitis that was efficiently treated with antifungal therapy and decreased immunosuppression regimen. Eight months later, a paradoxical worsening of neurological symptoms and neuroradiological findings led to the diagnosis of IRIS. A short course of high-dose steroid therapy allowed complete resolution of neurological symptoms. This report highlights the challenge for physicians to distinguish IRIS from a relapsing cryptococcal infection. Clinical improvement of cryptococcosis-associated IRIS by anti-inflammatory drugs needs to be confirmed among SOT recipients.

Cutaneous cryptococcosis in solid organ transplant recipients

Clinical manifestations, treatment, and outcomes of cutaneous cryptococcosis in solid organ transplant (SOT) recipients are not fully defined. In a prospective cohort comprising 146 SOT recipients with cryptococcosis, we describe the presentation, antifungal therapy, and outcome of cutaneous cryptococcal disease. Cutaneous cryptococcosis was documented in 26/146 (17.8%) of the patients and manifested as nodular/mass (34.8%), maculopapule (30.4%), ulcer/pustule/abscess (30.4%), and cellulitis (30.4%) with 65.2% of the skin lesions occurred in the lower extremities. Localized disease developed in 30.8% (8/26), and disseminated disease in 69.2% (18/26) with involvement of the central nervous system (88.9%, 16/18), lung (33.3%, 6/18), or fungemia (55.6%, 10/18). Fluconazole (37.5%) was employed most often for localized and lipid formulations of amphotericin B (61.1%) for disseminated disease. Overall mortality at 90 days was 15.4% (4/26) with 16.7% in disseminated and 12.5% in localized disease (P = 0.78). SOT recipients who died were more likely to have renal failure (75.0% vs. 13.6%, P = 0.028), longer time to onset of disease after transplantation (87.5 vs. 22.6 months, P = 0.023), and abnormal mental status (75% vs. 13.6%, P = 0.028) than those who survived. Cutaneous cryptococcosis represents disseminated disease in most SOT recipients and preferentially involves the extremities. Outcomes with appropriate management were comparable between SOT recipients with localized and disseminated cryptococcosis.

Cryptococcal immune reconstitution syndrome during steroid withdrawal treated with hydroxychloroquine

We present a case report of cryptococcal immune reconstitution syndrome (IRS), in a non HIV infected patient, which we treated with hydroxychloroquine with successful results. We briefly review cryptococcal IRS, possible mechanisms of action of hydroxychloroquine as an immunomodulatory agent, and its potential role in management of IRS.

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.

Risk factors for immune reconstitution inflammatory syndrome under combination antiretroviral therapy can be aetiology-specific

In order to discriminate general from aetiology-specific risk factors for immune reconstitution inflammatory syndrome (IRIS), we followed up, during six months, 99 patients with advanced HIV infection commencing antiretroviral therapy (ART) without active opportunistic infections or evident inflammation. IRIS predictors were determined by univariate analysis using clinical data from 76 ART-responding patients either completing follow-up or developing IRIS, and by multivariate analysis of inflammation, disease progression and nutrition status variables. We identified 23 primary IRIS events (30.3%). Univariate predictors for all IRIS events were higher platelet counts and lower CD4/CD8 ratio, whereas subclinical inflammation was the multivariate predictor. Platelets, alkaline phosphatase levels and %CD8 T-cells in univariate analysis also predicted mycobacteria-associated IRIS independently, remaining elevated during follow-up. Herpesvirus IRIS was predicted by platelets and inflammation. Indicators of advanced HIV disease and subclinical inflammation jointly predict IRIS, and some are specific of the underlying microbial aetiology, possibly explaining previous reports.

Fungal infections in transplant and oncology patients

Recent shifts in the epidemiology of invasive fungal infections (IFIs) among transplant and oncology populations have led to new recommendations on treatment; however, they have also brought new controversies. New pharmacologic therapies are being studied and guidelines for management of several IFIs have been changed accordingly. More information is being discovered about unique genetic factors that put some transplant recipients at greater risk than others for fungal infection. The role of immunomodulation continues to be investigated, and the delicate balance of maintaining some immune integrity while assuring protection of the graft remains critical. For transplant and oncology patients, the diagnosis and management of IFIs remain challenging, and improving outcomes depends on continued progress in all of these arenas. This article highlights recent advances and important factors to consider when treating transplant and oncology patients with IFIs.

Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the infectious diseases society of america

Cryptococcosis is a global invasive mycosis associated with significant morbidity and mortality. These guidelines for its management have been built on the previous Infectious Diseases Society of America guidelines from 2000 and include new sections. There is a discussion of the management of cryptococcal meningoencephalitis in 3 risk groups: (1) human immunodeficiency virus (HIV)-infected individuals, (2) organ transplant recipients, and (3) non-HIV-infected and nontransplant hosts. There are specific recommendations for other unique risk populations, such as children, pregnant women, persons in resource-limited environments, and those with Cryptococcus gattii infection. Recommendations for management also include other sites of infection, including strategies for pulmonary cryptococcosis. Emphasis has been placed on potential complications in management of cryptococcal infection, including increased intracranial pressure, immune reconstitution inflammatory syndrome (IRIS), drug resistance, and cryptococcomas. Three key management principles have been articulated: (1) induction therapy for meningoencephalitis using fungicidal regimens, such as a polyene and flucytosine, followed by suppressive regimens using fluconazole; (2) importance of early recognition and treatment of increased intracranial pressure and/or IRIS; and (3) the use of lipid formulations of amphotericin B regimens in patients with renal impairment. Cryptococcosis remains a challenging management issue, with little new drug development or recent definitive studies. However, if the diagnosis is made early, if clinicians adhere to the basic principles of these guidelines, and if the underlying disease is controlled, then cryptococcosis can be managed successfully in the vast majority of patients.

Immune reconstitution inflammatory syndrome and solid organ transplant recipients: are children protected?

The IRIS was initially described in HIV-positive patients as a sudden clinical deterioration after the introduction of highly active retroviral therapy. It is believed that IRIS is caused by a restored and exaggerated inflammatory immune response to different infectious or non-infectious triggers. This abnormal response is the consequence of an imbalance between pro-inflammatory and anti-inflammatory states. Recently, IRIS has also been reported in adult SOT recipients, causing local and systemic manifestations, and compromising long-term graft function and patient survival. However, IRIS has to date not been reported in pediatric SOT recipients. Here we review what is known and speculated about the pathogenesis of IRIS and propose that children may be relatively protected from IRIS.

Immune reconstitution inflammatory syndrome in non-HIV immunocompromised patients

PURPOSE OF REVIEW

In the era of highly active antiretroviral therapy, immune reconstitution inflammatory syndrome has become well recognized in the HIV-infected population. However, little is known about its occurrence in non-HIV immunocompromised hosts. The present review aims to propose the pathogenesis of immune reconstitution inflammatory syndrome, summarize its occurrence in immunocompromised patients without HIV infection, and suggest potential treatment options.

RECENT FINDINGS

Immune reconstitution inflammatory syndrome is exuberant and dysregulated inflammatory responses to invading microorganisms. It manifests when an abrupt shift of host immunity from an anti-inflammatory and immunosuppressive status towards a pathogenic proinflammatory state occurs as a result of rapid decreases or removal of factors promoting immunosuppression or inhibiting inflammation. In addition to HIV-infected patients, immune reconstitution inflammatory syndrome has also been observed in solid organ transplant recipients, women during the postpartum period, neutropenic patients, and tumor necrosis factor antagonist recipients. Corticosteroids are the most commonly employed treatment, whereas other potential agents based on its pathogenesis deserve further investigation.

SUMMARY

Non-HIV immunocompromised hosts develop immune reconstitution inflammatory syndrome when the sudden change in the dominant T helper responses to inflammation is not well balanced by anti-inflammatory responses. Judicious manipulation of host immunity and timely recognition of immune reconstitution inflammatory syndrome as we deal with the infections in these populations is critical to limit or avoid the harm by immune reconstitution inflammatory syndrome.

The pathophysiology of the acute phase of human bartonellosis resembles AIDS

Human bartonellosis is a South American anthroponosis caused by Bartonella bacilliformis. The disease has an acute phase characterized by invasion of red blood cells by parasites, and consequent severe anemia; and a chronic phase presenting with benign vascular tumors. During the acute phase, affected individuals are prone to developing opportunistic infections with a variety of organisms similar to the ones seen in AIDS. After antibiotic treatment is instituted, a subgroup of patients may develop atypical symptoms which potentially represent clinical manifestations of the restoration of macrophage function. We speculate that the pathophysiology of the acute phase of human bartonellosis resembles AIDS, with a period of immunosuppression following the infection and later, clinical manifestations of immune reconstitution subsequent to treatment.

Colitis as a manifestation of infliximab-associated disseminated cryptococcosis

The ability of tumor necrosis factor (TNF)-alpha inhibitors to impair pivotal pro-inflammatory host defenses may facilitate the development of disseminated cryptococcosis. Gastrointestinal (GI) tract disease is an unusual presentation of this yeast infection. We describe a unique case of disseminated cryptococcosis presenting as colitis that mimicked an exacerbation of Crohn's disease in a TNF-alpha inhibitor recipient. Review of existing literature shows that in immunocompromised patients, GI cryptococcosis invariably coexists with disseminated cryptococcosis, often lacks prominent GI symptomatology, and is primarily diagnosed postmortem. In cases with opportunistic infections, discontinuation of TNF-alpha inhibitors is a common practice, however rapid rebound of inflammatory responses may incur the risk of immune reconstitution syndrome.

Cryptococcosis: an emerging respiratory mycosis

Cryptococcosis occurs in immunocompromised and, in special cases, immunocompetent individuals. There have been a number of important advances in the field, but, despite current treatment, patients continue to die of the infection. This article reviews cryptococcosis epidemiology, clinical features, and management. Current knowledge is incomplete, however, so this article also discusses some of the gaps in the present understanding of cryptococcosis. The hope is that current research striving to understand the mechanisms of host evasion of Cryptococcus will result in improved treatment regimens that decrease both the mortality and morbidity of cryptococcosis.

Cryptococcal lung disease

PURPOSE OF REVIEW

Cryptococcosis is an important opportunistic fungal infection, especially in the immunocompromised patient. Meningitis is the most common manifestation of cryptococcosis; however, cryptococcal lung disease is probably underdiagnosed, and knowledge of epidemiology, diagnosis, and treatment is necessary.

RECENT FINDINGS

Cryptococcal lung disease ranges from asymptomatic colonization or infection to severe pneumonia with respiratory failure. Clinical presentation of pulmonary cryptococcosis is highly variable and often is related to the immune status of the patient. There have been many important clinical trials outlining treatment of cryptococcal meningitis in patients with AIDS, but there is a lack of treatment data available for patients with cryptococcal lung disease. Treatment recommendations for cryptococcal lung disease are made on the basis of host immune status and severity of clinical illness. For less severe disease, fluconazole therapy is recommended. In immunocompromised patients, or those with severe disease, induction therapy with an amphotericin B preparation and flucytosine, followed by fluconazole as consolidation and maintenance therapy, is recommended.

SUMMARY

Cryptococcal lung disease is an important and probably underdiagnosed infection. Knowledge of the epidemiology, diagnostic methodologies, and treatment is needed to ensure good patient outcomes.

Fungal infections after lung transplantation

PURPOSE OF REVIEW

Lung transplant's Achilles heel is chronic rejection. This is the reason why high immunosuppression is used, which leads to the development of infections. Fungal infections are a great obstacle in lung transplant patients' progress, not only because of their impact on patient survival, but also because fungal infections indirectly have an influence on the graft's progress. This review highlights the changing spectrum of invasive fungal infections as well as the most recent developments in diagnosis, prophylaxis, treatment and monitoring of lung transplantation.

RECENT FINDINGS

Fungal infections have a bimodal presentation: early onset, in relation to difficult postsurgeries and prior colonizations, and late onset, primarily in relation to chronic rejection and terminal renal insufficiency. The clinical impact of non-Aspergillus moulds is still unknown. Recent efforts have focused on nonculture-based methods to establish a rapid diagnosis. However, multicentre studies are needed to establish the diagnostic value of galactomannan antigen assay in invasive aspergillosis in lung transplantation. In addition, studies of the sensitivity and specificity of PCR assays are required to establish their diagnostic value. Unfortunately, only some advances in the diagnosis of aspergillosis have been achieved.

SUMMARY

Prophylaxis should be tailored according to the different individual patient's risk status. Combined treatments, including surgical therapy, may be useful in some patients.

Cryptococcal granulomatous interstitial nephritis and dissemination in a patient with untreated lupus nephritis

Infection is a significant cause of mortality and morbidity in systemic lupus erythematosus (SLE). There are many reports of cryptococcal infection in patients with SLE, on immunosuppression. However, untreated lupus with cryptococcal infection and dissemination is rare. CD4 lymphopaenia is not reported in such patients. We describe a patient with untreated SLE to be having cryptococcal granulomatous interstitial nephritis and dissemination with CD4 lymphopaenia.

Evidence of a role for monocytes in dissemination and brain invasion by Cryptococcus neoformans

The pathogenesis of cryptococcosis, including the events leading to the production of meningoencephalitis, is still largely unknown. Evidence of a transcellular passage of Cryptococcus neoformans across the blood-brain barrier (BBB) and subsequent BBB disruption exists, but the paracellular passage of free yeasts and the role of monocytes in yeast dissemination and brain invasion (Trojan horse method) remain uncertain. We used our model of disseminated cryptococcosis, in which crossing of the BBB starts 6 h after intravenous inoculation, to study paracellular passage of the BBB. We prepared bone marrow-derived monocytes (BMDM) infected in vitro with C. neoformans (BMDM yeasts) and free yeasts and measured fungal loads in tissues. (i) Spleen and lung CFU were >2-fold higher in mice treated with BMDM yeasts than in those treated with free yeasts for 1 and 24 h (P < 0.05), while brain CFU were increased (3.9 times) only at 24 h (P < 0.05). (ii) By comparing the kinetics of brain invasion in naïve mice and in mice with preestablished cryptococcosis, we found that CFU were lower in the latter case, except at 6 h, when CFU from mice inoculated with BMDM yeasts were comparable to those measured in naïve mice and 2.5-fold higher than those in mice with preestablished cryptococcosis who were inoculated with free yeasts. (iii) Late phagocyte depletion obtained by clodronate injection reduced disease severity and lowered the fungal burden by 40% in all organs studied. These results provide evidence for Trojan horse crossing of the BBB by C. neoformans, together with mechanisms involving free yeasts, and overall for a role of phagocytes in fungal dissemination.

Cryptococcosis in solid organ transplant recipients: current state of the science

Cryptococcosis remains a significant opportunistic infection in solid organ transplant recipients. Disease presentation and outcomes may be affected by, among other factors, the use of calcineurin inhibitor immunosuppressive agents. It is being increasingly recognized that rapid reversal of immunosuppression in transplant recipients treated for cryptococcosis incurs the risk of immune reconstitution inflammatory syndrome, which resembles worsening disease or relapse. This review summarizes the current state of knowledge regarding cryptococcosis in transplant recipients and highlights areas where future investigations are needed to further optimize outcomes for these patients.

Immune reconstitution syndrome after voriconazole treatment for cryptococcal meningitis in a liver transplant recipient

A new entity that comprises symptomatic worsening of an infectious or inflammatory process despite appropriate treatment was described a few years ago in human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy. This entity was defined as immune reconstitution syndrome, and it is believed to result from an intense inflammatory reaction in patients with an appropriately treated infection who recover immunological status. Recently, immune reconstitution syndrome has also been described in transplant recipients, although information is scarce because of its low incidence. Here we describe a new case of immune reconstitution syndrome in a liver transplant recipient after successful treatment of cryptococcal meningitis.

Recommendations for the treatment of established fungal infections

Evidence-based guidelines for the treatment of established fungal infections in the adult haematology/oncology setting were developed by a national consensus working group representing clinicians, pharmacists and microbiologists. These updated guidelines replace the previous guidelines published in the Internal Medicine Journal by Slavin et al. in 2004. The guidelines are pathogen-specific and cover the treatment of the most common fungal infections including candidiasis, aspergillosis, cryptococcosis, zygomycosis, fusariosis, scedosporiosis, and dermatophytosis. Recommendations are provided for management of refractory disease or salvage therapies, and special sites of infections such as the cerebral nervous system and the eye. Because of the widespread use newer broad-spectrum triazoles in prophylaxis and empiric therapy, these guidelines should be implemented in concert with the updated prophylaxis and empiric therapy guidelines published by this group.

Therapeutic efficacy of a conjugate vaccine containing a peptide mimotope of cryptococcal capsular polysaccharide glucuronoxylomannan

Vaccination with P13, a peptide mimotope of the cryptococcal capsular polysaccharide glucuronoxylomannan (GXM), has been shown to confer protection against a subsequent lethal Cryptococcus neoformans challenge. In this study, we sought to investigate whether P13-based vaccines could be effective in an already-established infection. To address this question, we developed a systemic chronic cryptococcal infection model. We vaccinated chronically infected mice with P13-protein conjugates and monitored their survival. Compared to the controls, the conjugates prolonged the survival of chronically infected mice. The degree of protection was a function of the mouse strain (BALB/c or C57BL/6), the carrier protein (tetanus toxoid or diphtheria toxoid), and the route of infection (intraperitoneal or intravenous). Serum GXM levels were correlated with the day of death, but the correlation was driven by the carrier protein and mouse strain. The passive transfer of heat-treated sera from P13 conjugate-vaccinated mice conferred protection to naïve BALB/c mice, indicating that antibody immunity could contribute to protection. The measurement of peripheral blood cytokine (gamma interferon [IFN-gamma], interleukin-10 [IL-10], and IL-6) gene expression showed that P13 conjugate-vaccinated BALB/c and C57BL/6 mice mounted a strong Th2 (IL-10)-like response relative to the Th1 (IFN-gamma)-like response, with the degree depending on the mouse strain and carrier protein. Taken together, our data suggest that a vaccine could hold promise in the setting of chronic cryptococcosis, and that vaccine efficacy could depend on immunomodulation and augmentation of the natural immune response of the host.

Novel immune regulatory pathways and their role in immune reconstitution syndrome in organ transplant recipients with invasive mycoses

Immune regulatory pathways involving the newly discovered T regulatory (Treg) and Th17 cells are amongst the principal targets of immunosuppressive agents employed in transplant recipients and key mediators of host inflammatory responses in fungal infections. These novel signaling pathways, in concert with or independent of Th1/Th2 responses, have potentially important implications for yielding valuable insights into the pathogenesis of immune reconstitution syndrome (IRS) in transplant recipients, for aiding the diagnosis of this entity, and for achieving a balance of immune responses that enhance host immunity while curbing unfettered inflammation in IRS.

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.

[Immune reconstitution inflammatory syndrome (IRIS)]

Overwhelming immune reaction resulting in granulomatous inflammation after infection with opportunistic pathogens has been termed immune reconstitution inflammatory syndrome (IRIS). IRIS has mainly been described in patients with human immunodeficiency virus (HIV). However, IRIS is not restricted to HIV-patients and may occur in other infections and immunodeficiencies. In our clinic, we experienced a Whipple's disease patient with IRIS. IRIS occurs mainly after initiation of the highly active anti-retroviral therapy (HAART). Soon after HAART initiation, a marked inflammatory reaction can occur, triggered by restoration of pathogen-specific immunity. IRIS may be targeted by various infective antigens, dead or dying infective antigens, host antigens, tumor antigens and other antigens, giving rise to a heterogenous range of clinical manifestations. Treatment should be optimized for the associated condition and initiated immediately. Glucocorticoids should be used in patients who are severely affected by IRIS.

Epidemiology and management of cryptococcal meningitis: developments and challenges

The significance of cryptococcal infection as a cause of human disease has dramatically evolved in recent years. The objective of this study was to outline the worldwide significance of cryptococcosis and review developments in the management of cryptococcal meningitis. Cryptococcus neoformans var. grubii remains an important cause of disease, particularly in hosts with acquired immunosuppression. Cryptococcus gattii, on the other hand, infects hosts with seemingly normal immune systems and a recent dramatic outbreak in a new ecologic environment highlights the emerging clinical significance of this fungal pathogen. The introduction of new antifungal agents and the adoption of strategies for controlling elevated intracranial pressure in cryptococcal meningitis have added to our therapeutic options. However, the mortality from this infection remains unacceptably high and we are faced with the specific challenges in the management of this disease.

Adjuvant corticosteroid therapy for chronic disseminated candidiasis

BACKGROUND

Chronic disseminated candidiasis (CDC) is typically observed during neutrophil recovery in patients with acute leukemia and requires protracted antifungal therapy.

OBJECTIVE

Our objective was to document the efficacy and tolerance of corticosteroid therapy (CST) in patients with symptomatic CDC, including those who experienced fever and abdominal pain despite ongoing antifungal therapy.

METHODS

We performed a retrospective, multicenter study involving 10 pediatric and adult patients who experienced ongoing symptomatic CDC despite receipt of appropriate antifungal therapy for whom adjuvant oral CST was initiated.

RESULTS

All cases of CDC were proven or probable, as determined on the basis of the European Organization for Research and Treatment of Cancer-Mycosis Study Group definition criteria, and occurred in patients with leukemia. CDC-attributable clinical symptoms resolved with CST, which was started a mean of 33.8 days after antifungal therapy had been initiated. Fever and abdominal pain disappeared a median of 4-5 days, and serum fibrinogen and C-reactive protein levels returned to normal values within 14-30 days. The median duration of hospitalization after CST initiation was 8.8 days. Hepatosplenic microabscesses decreased or disappeared within a mean period of 107 days (range, 30-210 days). No relapses of CDC were observed during a median duration of follow-up of 6.5 years (range, 4-9 years).

CONCLUSIONS

In children and adults who experience persistently symptomatic CDC despite ongoing receipt of antifungal therapy, CST involving a prednisone equivalent at a dosage of > or =0.5 mg/kg per day for at least 3 weeks is associated with a prompt resolution of symptoms and of inflammatory response. These findings support the pathophysiological hypothesis that CDC belongs to the spectrum of fungus-related immune reconstitution inflammatory syndrome.

Disseminated sporotrichosis presenting with granulomatous inflammatory multiple mononeuropathies

We describe a case of sporotrichosis that disseminated to involve multiple nerves after initiation of immunosuppressive therapy and then precipitously worsened after withdrawal of therapy. This case illustrates that multiple mononeuropathies are not always caused by vasculitis, and a correct pathological diagnosis should be established before treatment. Based on clinical and pathological features, the mechanism of neuropathy may have been due to either direct nerve infection or a bystander effect of inflammatory/immune damage or, perhaps more likely, to both mechanisms.