A pilot study of the discontinuation of antifungal therapy for disseminated cryptococcal disease in patients with acquired immunodeficiency syndrome, following immunologic response to antiretroviral therapy

Global guideline for the diagnosis and management of cryptococcosis: an initiative of the ECMM and ISHAM in cooperation with the ASM

Cryptococcosis is a major worldwide disseminated invasive fungal infection. Cryptococcosis, particularly in its most lethal manifestation of cryptococcal meningitis, accounts for substantial mortality and morbidity. The breadth of the clinical cryptococcosis syndromes, the different patient types at-risk and affected, and the vastly disparate resource settings where clinicians practice pose a complex array of challenges. Expert contributors from diverse regions of the world have collated data, reviewed the evidence, and provided insightful guideline recommendations for health practitioners across the globe. This guideline offers updated practical guidance and implementable recommendations on the clinical approaches, screening, diagnosis, management, and follow-up care of a patient with cryptococcosis and serves as a comprehensive synthesis of current evidence on cryptococcosis. This Review seeks to facilitate optimal clinical decision making on cryptococcosis and addresses the myriad of clinical complications by incorporating data from historical and contemporary clinical trials. This guideline is grounded on a set of core management principles, while acknowledging the practical challenges of antifungal access and resource limitations faced by many clinicians and patients. More than 70 societies internationally have endorsed the content, structure, evidence, recommendation, and pragmatic wisdom of this global cryptococcosis guideline to inform clinicians about the past, present, and future of care for a patient with cryptococcosis.

A Call to Arms: Quest for a Cryptococcal Vaccine

Cryptococcosis remains a significant cause of morbidity and mortality world-wide, particularly among AIDS patients. Yet, to date, there are no licensed vaccines clinically available to treat or prevent cryptococcosis. In this review, we provide a rationale to support continued investment in Cryptococcus vaccine research, potential challenges that must be overcome along the way, and a literature review of the current progress underway towards developing a vaccine to prevent cryptococcosis.

The war on cryptococcosis: A Review of the antifungal arsenal

Cryptococcal meningitis is the most common central nervous system infection in the world today. It occurs primarily, but not exclusively, in immunocompromised individuals and despite substantial improvement in management of clinical events like AIDS, the numbers of cases of cryptococcosis remain very high. Unfortunately, despite several antifungal agents available for treatment, morbidity and mortality rates remain high with this fungal infection. In this Review, we will describe the treatments and strategies for success, identify the failures, and provide insights into the future developments / improvements for management. This sugar-coated yeast can play havoc within the human brain. Our goals must be to either prevent or diagnose disease early and treat aggressively with all our clinical tools when disease is detected.

Integrated therapy for HIV and cryptococcosis

Cryptococcosis has been one of the most common opportunistic infections and causes of mortality among HIV-infected patients, especially in resource-limited countries. Cryptococcal meningitis is the most common form of cryptococcosis. Laboratory diagnosis of cryptococcosis includes direct microscopic examination, isolation of Cryptococcus from a clinical specimen, and detection of cryptococcal antigen. Without appropriate treatment, cryptococcosis is fatal. Early diagnosis and treatment is the key to treatment success. Treatment of cryptococcosis consists of three main aspects: antifungal therapy, intracranial pressure management for cryptococcal meningitis, and restoration of immune function with antiretroviral therapy (ART). Optimal integration of these three aspects is crucial to achieving successful treatment and reducing the mortality. Antifungal therapy consists of three phases: induction, consolidation, and maintenance. A combination of two drugs, i.e. amphotericin B plus flucytosine or fluconazole, is preferred in the induction phase. Fluconazole monotherapy is recommended during consolidation and maintenance phases. In cryptococcal meningitis, intracranial pressure rises along with CSF fungal burden and is associated with morbidity and mortality. Aggressive control of intracranial pressure should be done. Management options include therapeutic lumbar puncture, lumbar drain insertion, ventriculostomy, or ventriculoperitoneal shunt. Medical treatment such as corticosteroids, mannitol, and acetazolamide are ineffective and should not be used. ART has proven to have a great impact on survival rates among HIV-infected patients with cryptococcosis. The time to start ART in HIV-infected patients with cryptococcosis has to be deferred until 5 weeks after the start of antifungal therapy. In general, any effective ART regimen is acceptable. Potential drug interactions between antiretroviral agents and amphotericin B, flucytosine, and fluconazole are minimal. Of most potential clinical relevance is the concomitant use of fluconazole and nevirapine. Concomitant use of these two drugs should be cautious, and patients should be monitored closely for nevirapine-associated adverse events, including hepatotoxicity. Overlapping toxicities of antifungal and antiretroviral drugs and immune reconstitution inflammatory syndrome are not uncommon. Early recognition and appropriate management of these consequences can reinforce the successful integrated therapy in HIV-infected patients with cryptococcosis.

Host immunity to Cryptococcus neoformans

Cryptococcosis is caused by the fungal genus Cryptococcus. Cryptococcosis, predominantly meningoencephalitis, emerged with the HIV pandemic, primarily afflicting HIV-infected patients with profound T-cell deficiency. Where in use, combination antiretroviral therapy has markedly reduced the incidence of and risk for disease, but cryptococcosis continues to afflict those without access to therapy, particularly in sub-Saharan Africa and Asia. However, cryptococcosis also occurs in solid organ transplant recipients and patients with other immunodeficiencies as well as those with no known immunodeficiency. This article reviews innate and adaptive immune responses to C. neoformans, with an emphasis on recent studies on the role of B cells, natural IgM and Fc gamma receptor polymorphisms in resistance to cryptococcosis.

Identification and characterization of Cryptococcus neoformans protein fractions that induce protective immune responses

Cryptococcus neoformans, the main causative agent of cryptococcosis, is a fungal pathogen that causes life-threatening meningoencephalitis in immunocompromised patients. To date, there is no vaccine or immunotherapy approved to treat cryptococcosis. Cell- and antibody-mediated immune responses collaborate to mediate optimal protection against C. neoformans infections. Accordingly, we identified cryptococcal protein fractions capable of stimulating cell- and antibody-mediated immune responses and determined their efficacy to elicit protection against cryptococcosis. Proteins were extracted from C. neoformans and fractionated based on molecular mass. The fractions were then evaluated by immunoblot analysis for reactivity to serum extracted from protectively immunized mice and in cytokine recall assays for their efficacy to induce pro-inflammatory and Th1-type cytokine responses associated with protection. MS analysis revealed a number of proteins with roles in stress response, signal transduction, carbohydrate metabolism, amino acid synthesis, and protein synthesis. Immunization with select protein fractions containing immunodominant antigens induced significantly prolonged survival against experimental pulmonary cryptococcosis. Our studies support using the combination of immunological and proteomic approaches to identify proteins that elicit antigen-specific antibody and Th1-type cytokine responses. The immunodominant antigens that were discovered represent attractive candidates for the development of novel subunit vaccines for treatment and/or prevention of cryptococcosis.

Cryptococcus antigens and immune responses: implications for a vaccine

Cryptococcosis is a fungal disease primarily occurring in immunocompromised individuals, such as AIDS patients, and is associated with high morbidity and mortality. However, cryptococcosis can occur within immunocompetent populations as observed during an outbreak in Vancouver Island, British Columbia, Canada, the Pacific Northwest and other regions of the USA and in Mediterranean Europe. Mortality rates due to cryptococcosis have significantly declined in economically developed countries since the widespread implementation of highly active antiretroviral therapy. However, the incidence and mortality of this disease remains high in economically undeveloped areas in Africa and Asia where HIV infections are high and availability of HAART is limited. The continuing AIDS epidemic coupled with the increased usage of immunosuppressive drugs to prevent organ transplant rejection or to treat autoimmune diseases has resulted in an increase in individuals at risk for developing cryptococcosis. The purpose of this review is to discuss the need, challenges and potential for developing vaccines against cryptococcosis.

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.

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.

Pharmacotherapy of cryptococcosis

Cryptococcus neoformans is an opportunistic fungal pathogen that causes central nervous system and pulmonary disease among immunocompromised patients. Recent studies highlight the high incidence of cryptococcosis among patients in certain resource-poor areas, where there is also a high incidence of AIDS. Despite the availability of antifungal agents with anticryptococcal activity, the mortality and treatment-failure rates associated with cryptococcosis remain unacceptably high. This article reviews current treatment strategies and the basis for these strategies, as well as prospects for future approaches to the treatment of cryptococcosis.

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.

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

OBJECTIVES

A proportion of HIV patients beginning antiretroviral therapy (ART) develop immune restoration disease (IRD). Immunological characteristics of IRD were investigated in a cohort of HIV patients beginning therapy in Kuala Lumpur, Malaysia.

METHODS

Peripheral blood mononuclear cells were collected at weeks 0, 6, 12, 24 and 48 of ART from five patients experiencing IRD [two with cryptococcal and three with Mycobacterium tuberculosis (Mtb) disease], eight non-IRD controls who had begun ART with CD4 T-cell counts of <100 cells/microL and 17 healthy controls. Leukocytes producing interferon-gamma (IFNgamma) were quantified by enzyme-linked immunospot assay after stimulation with purified protein derivative (PPD), early secretory antigenic target-6 (ESAT-6), Cryptococcus neoformans or Cytomegalovirus antigens. Plasma immunoglobulin (IgG) antibodies reactive with these antigens were assessed by enzyme-linked immunosorbent assay. Proportions of activated (HLA-DR(hi)) and regulatory (CD25 CD127(lo) and CTLA-4(+)) CD4 T-cells were quantified by flow cytometry.

RESULTS

Plasma HIV RNA declined and CD4 T-cell counts rose within 8-27 weeks on ART. Mtb IRD patients displayed elevated IFNgamma responses and/or plasma IgG to PPD, but none responded to ESAT-6. Cryptococcal IRD occurred in patients with low baseline CD4 T-cell counts and involved clear IFNgamma and antibody responses to cryptococcal antigen. Proportions of activated and regulatory CD4 T-cells declined on ART, but remained higher in patients than in healthy controls. At the time of IRD, proportions of activated CD4 T-cells and regulatory CD4 T-cells were generally elevated relative to other patients.

CONCLUSIONS

Cryptococcal and Mtb IRD generally coincide with peaks in the proportion of activated T-cells, pathogen-specific IFNgamma responses and reactive plasma IgG. IRD does not reflect a paucity of regulatory CD4 T-cells.

Long-term outcome of AIDS-associated cryptococcosis in the era of combination antiretroviral therapy

BACKGROUND

Immune restoration following combination antiretroviral therapy (cART) questions the maintenance of prophylaxis among HIV-infected patients with cryptococcosis.

OBJECTIVE

To describe the long-term outcome after the diagnosis of cryptococcosis at the cART era.

DESIGN

Multicentre cohort of patients with a diagnosis of cryptococcosis between 1996 and 2000, follow-up until December 2002. Comparison with a historical cohort (1990-1994) for survival.

SETTING

Eighty-four French AIDS clinical centres.

PATIENTS

Two-hundred and forty HIV-infected adult patients at the cART era and 149 at the pre-cART era experiencing a first episode of culture-confirmed cryptococcosis.

RESULTS

In the cART era, 82/189 patients surviving more than 3 months after initiation of antifungal therapy had their maintenance therapy interrupted with a subsequent median follow-up of 19 months. Their relapse rate per 100 person-years was 0.9 [95% confidence interval (CI),0.0-2.0]. When considering the whole cART cohort, probability of reaching negative serum cryptococcal antigen was 71% after 48 months of follow-up. A CD4 cell count < 100/microl [relative risk (RR), 5.5; 95% CI, 1.3-22.2], antifungal therapy < 3 months over the past 6 months [RR, 5.0; 95% CI, 1.1-22.3] and serum cryptococcal antigen titre > or = 1/512 [RR, 3.5; 95% CI, 1.1-10.8] were associated with a higher rate of cryptococcosis relapse. The mortality rate per 100 person-years was 15.3 [95% CI,12.2-18.4] in the cART era versus 63.8 [95% CI,53.0-74.9] in the pre-cART era although early mortality did not differ between the two periods.

CONCLUSION

Overall survival after cryptococcosis has dramatically improved at the cART era. Immune restoration and low serum cryptococcal antigen titres are associated with lower cryptococcosis relapse rates.

Cryptococcal disease and HIV infection

In the era of highly active antiretroviral therapy for the treatment of HIV infection, the dramatic reductions in mortality and morbidity associated with immune reconstitution have included a marked decline in the incidence of opportunistic infections. Cryptococcus neoformans is a yeast that causes predominantly neurological disease in immunocompromised individuals, in particular those with HIV infection. It continues to be an important diagnosis in developing areas and amongst late presenters in parts of the world with access to highly active antiretroviral therapy. This article reviews the epidemiology, clinical features and management of cryptococcal disease in HIV-infected patients, particularly focusing on the history of, current guidelines for and future developments in antifungal therapy.

Prevention of cryptococcosis in HIV-infected patients with limited access to highly active antiretroviral therapy: evidence for primary azole prophylaxis

Despite advances in the treatment of HIV disease, the incidence and mortality of invasive cryptococcal disease remain significant. A matched, case-control study was performed to examine the impact of highly active antiretroviral therapy (HAART) and azole use on the incidence of invasive cryptococcal disease in HIV-infected patients. The study was performed at a metropolitan hospital with a large indigent population and an incidence of seven cases of cryptococcal disease per 1000 persons with AIDS. Bivariate analysis, matched on CD4 count, revealed that both HAART use [odds ratio (OR) 0.43; 95% confidence interval (CI) 0.23-0.99] and azole use (OR 0.14; 95% CI 0.06-0.34) had a protective effect. Conditional logistic regression stratified on CD4 lymphocyte count revealed a protective role for azole use (OR 0.15; 95% CI 0.06-0.40) but not for HAART use (OR 0.47; 95% CI 0.18-1.26). Of note, the prevalence of HAART use was low in both cases and controls, with only 12% of cases and 23% of controls on HAART. The results of this study support previous evidence that azole use prevents invasive cryptococcal disease. Although current guidelines for the prophylaxis of opportunistic infections do not suggest routine prophylaxis for cryptococcal infection, this issue should be reconsidered, especially in populations that have a low prevalence of HAART use.

Identification and characterization of an SKN7 homologue in Cryptococcus neoformans

Cryptococcus neoformans is an encapsulated fungal pathogen that primarily infects the central nervous system of immunocompromised individuals, causing life-threatening meningoencephalitis. The capacity of C. neoformans to subvert host defenses and disseminate by intracellular parasitism of alveolar macrophages in the immune-compromised host has led to studies to evaluate genes associated with C. neoformans resistance to oxidative stress. In the present study, we identify and characterize a C. neoformans homologue to SKN7, a transcription factor in Saccharomyces cerevisiae that regulates the oxidative stress response, cell cycle, and cell wall biosynthesis. To examine the contribution of SKN7 in the pathogenesis of fungal infections, we created skn7 mutants via targeted disruption. The skn7 mutants were observed to be more susceptible to reactive oxygen species in vitro and were significantly less virulent than the wild-type strain and a reconstituted strain as measured by cumulative survival in the mouse inhalational model. The Skn7 protein was observed to be important for expression of thioredoxin reductase in response to oxidative challenge. Interestingly, skn7 mutants were also observed to flocculate following in vitro culture, a novel phenotype not observed in skn7 mutants derived from other fungi. These findings demonstrate that SKN7 contributes to the virulence composite but is not required for pathogenicity in C. neoformans. In addition, flocculation of C. neoformans skn7 mutants suggests a potentially unique function of SKN7 not previously observed in other cryptococcal strains or skn7 mutants.

Evaluation of host immune responses to pulmonary cryptococcosis using a temperature-sensitive C. neoformans calcineurin A mutant strain

Cryptococcus neoformans is an opportunistic fungal pathogen that threatens individuals with impaired cell-mediated immunity (CMI). Presently, there are no standardized vaccines available to prevent cryptococcal infections and conventional anti-fungal drug therapy does not induce host immune reactivity and thus cannot efficiently resolve C. neoformans infections in immunocompromised individuals. The present study was designed to characterize pulmonary immune responses following infection with an avirulent temperature-sensitive (ts) mutant, calcineurin A1 (cna1) compared to the pathogenic C. neoformans strain H99 and its potential to induce protective anti-cryptococcal immunity. Host CMI responses in cna1-inoculated mice were observed to be dose-dependent, and comprise increases in pulmonary macrophages and CD4(+) T lymphocytes. However, cytokine analysis demonstrated a mixed pulmonary cytokine response (increases in IL-4, and MCP-1) with no induction of IFN-gamma. Also, pre-immunization with the ts cna1 mutant did not result in protection from a subsequent secondary pulmonary infection with the pathogenic C. neoformans strain H99. Taken together, these results suggest that host pulmonary CMI responses to the ts cna1 mutant that is eventually eliminated from the host without the induction of IFN-gamma appear to be dose-dependent, diverse, and require further stimulation to induce C. neoformans-specific Th1-type cytokine responses to resolve subsequent experimental pulmonary cryptococcal infections.

Diagnosis and Management of Central Nervous System Histoplasmosis

Two cases of Histoplasma meningitis are presented, illustrating the difficulty in diagnosis and treatment. The first case occurred in a patient with acquired immunodeficiency syndrome as a relapse of disseminated histoplasmosis and resolved after prolonged treatment and ongoing antiretroviral therapy. The second case occurred in a cardiac allograft recipient as meningitis and focal brain lesions that responded to liposomal amphotericin B, but the patient died shortly after therapy was completed. Unfortunately, there are no prospective studies addressing the diagnosis and management of patients with histoplasmosis of the central nervous system from which to provide evidence-based guidelines for care. In the absence of such data, an approach will be presented on the basis of our experience and opinions.

Evaluation and management of Fungal infections in Immunocompromised patients

As the population of chronically immunosuppressed individuals continues to grow, the prevalence of fungal infections is increasing. Fungal infections in this patient population represent challenges in diagnosis and management. This article will review the common superficial and invasive mycoses that occur in the solid organ transplant and HIV-infected populations. Disease presentations are reviewed, but emphasis is placed on cutaneous manifestations. Recent advances in antifungal therapy and their direct application to specific diseases provide important new approaches to this complex and often seriously ill patient population.

[Treatment and prophylaxis of opportunistic infections in the course of HIV disease: a state of the art in 2004. Part 2: Viral, fungal and bacterial infections]

Remarkable progress has been made in antiretroviral therapeutics, as well as in the prophylaxis and treatment of opportunistic infections, since the beginning of the AIDS epidemic. The patient's life expectancy and quality of life have consequently improved, thanks to better management of opportunistic diseases. The introduction of protease inhibitors-containing regimen (i.e. highly active antiretroviral therapy or HAART), since 1996, has drastically reduced the incidence of opportunistic infections by restoring immunity. The large panel of antiretroviral drugs responsible for frequent sustained viral and immune responses has thus allowed a new definition of guidelines for the prophylaxis and treatment of opportunistic infections. A better use of prophylactic drugs should help to reduce the risk of drug-related toxicity and pharmaceutical interactions. It should also decrease the cost of HIV management and eventually increase compliance to treatment and quality of life.

Safety of Discontinuation of Maintenance Therapy for Disseminated Histoplasmosis after Immunologic Response to Antiretroviral Therapy

We performed a prospective observational study to assess the safety of stopping maintenance therapy for disseminated histoplasmosis among human immunodeficiency virus infected patients after response to antiretroviral therapy. All subjects received at least 12 months of antifungal therapy and 6 months of antiretroviral therapy before entry. Negative results of fungal blood cultures, urine and serum Histoplasma antigen level of <4.1 units, and CD4+ T cell count of >150 cells/mm3 were required for eligibility. Thirty-two subjects were enrolled; the median CD4+ T cell count at study entry was 289 cells/mm3. No relapses of histoplasmosis occurred after a median duration of follow-up of 24 months. This corresponded to an observed relapse rate of 0 cases per 65 person-years. The median CD4+ T cell count at final study visit was 338 cells/mm3. Discontinuation of antifungal maintenance therapy appears to be safe for patients with acquired immunodeficiency syndrome with previously treated disseminated histoplasmosis and sustained immunologic improvement in response to antiretroviral therapy.

Immunogenicity and efficacy of Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan peptide mimotope-protein conjugates in human immunoglobulin transgenic mice

Peptide mimotopes of capsular polysaccharides have been proposed as antigens for vaccines against encapsulated pathogens. In this study, we determined the antibody response to and efficacy of P13, a peptide mimetic of the Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan (GXM), in mice that produce human antibodies. P13 was conjugated to tetanus toxoid (TT) or diphtheria toxoid (DT) and administered subcutaneously in Alhydrogel with or without CpG to mice transgenic for human immunoglobulin loci (XenoMouse mice) and expressing either immunoglobulin G2 (IgG2) (G2 mice) or IgG4 (G4 mice). Mice were vaccinated and revaccinated two or three times. The serum antibody responses of the mice to GXM and P13 and antibody idiotype expression were analyzed by an enzyme-linked immunosorbent assay. The results showed that both P13-TT and P13-DT were antigenic, inducing a mimetic response to P13 in both G2 and G4 mice, and immunogenic, inducing a mimotope response including VH3 (idiotype)-positive antibodies to GXM in G2 but not G4 mice. CpG led to higher titers of IgG to P13 and GXM in P13-TT-vaccinated G2 mice. C. neoformans challenge of P13-protein conjugate-vaccinated and control G2 mice induced anamnestic IgG- and VH3-positive responses to GXM and was associated with a significantly decreased risk of death and a prolongation of survival in P13-DT-vaccinated mice compared to phosphate-buffered saline-treated or protein carrier-vaccinated mice. These findings reveal that P13 elicited a human antibody response with VH3 expression in human immunoglobulin transgenic mice that has been observed for human antibodies to GXM and support the concept that peptide mimotope-based vaccines may hold promise for the treatment of C. neoformans infections.

Discontinuation of maintenance therapy for cryptococcal meningitis in patients with AIDS treated with highly active antiretroviral therapy: an international observational study

We conducted a retrospective, multicenter study evaluating the safety of discontinuing maintenance therapy for cryptococcal meningitis after immune reconstitution. Inclusion criteria were a previous definitive diagnosis of cryptococcal meningitis, a CD4 cell count of >100 cells/microL while receiving highly active antiretroviral therapy (HAART), and the subsequent discontinuation of maintenance therapy for cryptococcal meningitis. The primary end point was relapse of cryptococcal disease. As of July 2002, 100 patients were enrolled. When maintenance therapy was discontinued, the median CD4 cell count was 259 cells/microL and the median plasma virus load was <2.30 log10 copies/mL, and serum cryptococcal antigen was undetectable in 56 patients. During a median follow-up period of 28.4 months (range, 6.7-64.5; 262 person-years), 4 events were observed (incidence, 1.53 events per 100 person-years; 95% confidence interval, 0.42-3.92). Three of these patients had a CD4 cell count of >100 cells/microL and a positive serum cryptococcal antigen test result during the recurrent episode. In conclusion, discontinuation of maintenance therapy for cryptococcal meningitis is safe if the CD4 cell count increases to >100 cells/microL while receiving HAART. Recurrent cryptococcal infection should be suspected in patients whose serum cryptococcal antigen test results revert back to positive after discontinuation of maintenance therapy.

Discontinuation of secondary prophylaxis for cryptococcal meningitis in human immunodeficiency virus-infected patients treated with highly active antiretroviral therapy: a prospective, multicenter, randomized study

A prospective, multicenter, randomized study was conducted with human immunodeficiency virus (HIV)-infected patients who were successfully treated for acute cryptococcal meningitis, were receiving secondary prophylaxis, and were naive for antiretroviral therapy. Patients were randomized to continue or discontinue secondary prophylaxis when the CD4 cell count had increased to >100 cells/microL and an undetectable HIV RNA level had been sustained for 3 months. At a median of 48 weeks after randomization, there were no episodes of cryptococcal meningitis in either group.

Discontinuation of secondary prophylaxis for Pneumocystis carinii pneumonia in human immunodeficiency virus-infected patients: a randomized trial by the CIOP Study Group

This subgroup analysis assessing secondary prophylaxis for Pneumocystis carinii pneumonia (PCP) describes a multicenter, open-labeled, randomized, controlled trial evaluating the discontinuation of PCP prophylaxis. The main inclusion criterion was a history of PCP and an increase in the CD4 cell count to >200 cells/microL associated with receipt of highly active antiretroviral therapy for >or=3 months. The primary end point was the development of definitive or presumptive PCP. A total of 146 patients were enrolled (77 in the treatment discontinuation arm). After >2 years, 1 definitive and 1 presumptive case of PCP were observed, both of which occurred in patients who discontinued therapy. In most patients, secondary prophylaxis for PCP can be safely discontinued after potent antiretroviral therapy is initiated, but the threshold of >200 CD4 cells/microL may not be considered absolutely safe. Patients who present with symptoms after discontinuation of secondary prophylaxis should be evaluated for PCP despite high CD4 count and complete virus suppression.