Tom Harrison

Adjunctive interferon-γ immunotherapy for the treatment of HIV-associated cryptococcal meningitis: a randomized controlled trial.

Background:Interferon-gamma (IFN&ggr;) is of key importance in the immune response to Cryptococcus neoformans. Mortality related to cryptococcal meningitis remains high, and novel treatment strategies are needed. We performed a randomized controlled trial to determine whether addition of IFN&ggr; to standard therapy increased the rate of clearance of cryptococcal infection in HIV-associated cryptococcal meningitis. Methods:Patients were randomized to amphotericin B 1 mg/kg per day and 5FC 100 mg/kg per day for 2 weeks (standard therapy), standard therapy and IFN&ggr;1b 100 &mgr;g days 1 and 3 (IFN&ggr; two doses), or standard therapy and IFN&ggr;1b 100 &mgr;g days 1, 3, 5, 8, 10 and 12 (IFN&ggr; six doses). Primary outcome was rate of clearance of cryptococcus from the cerebrospinal fluid (CSF) (early fungicidal activity, EFA) calculated from serial quantitative cultures, previously shown to be independently associated with survival. Results:Rate of fungal clearance was significantly faster in IFN&ggr; containing groups than with standard treatment. Mean EFA [log colony forming unit (CFU)/ml per day] was −0.49 with standard treatment, −0.64 with IFN&ggr; two doses, and −0.64 with IFN&ggr; six doses. Difference in EFA was −0.15 [confidence interval (95% CI) −0.02 to −0.27, P = 0.02] between standard treatment and IFN&ggr; two doses, and −0.15 (95% CI −0.05 to −0.26, P = 0.006) between standard treatment and IFN&ggr; six doses. Mortality was 16% (14/88) at 2 weeks and 31% (27/87) at 10 weeks, with no significant difference between groups. All treatments were well tolerated. Conclusion:Addition of short-course IFN&ggr; to standard treatment significantly increased the rate of clearance of cryptococcal infection from the CSF, and was not associated with any increase in adverse events. Two doses of IFN&ggr; are as effective as six doses.

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 × 106 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 γ, tumour necrosis factor α, 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.

Relationship of cerebrospinal fluid pressure, fungal burden and outcome in patients with cryptococcal meningitis undergoing serial lumbar punctures

Objectives:To assess impact of serial lumbar punctures on association between cerebrospinal fluid (CSF) opening pressure and prognosis in HIV-associated cryptococcal meningitis; to explore time course and relationship of opening pressure with neurological findings, CSF fungal burden, immune response, and CD4 cell count. Design:Evaluation of 163 HIV-positive ART-naive patients enrolled in three trials of amphotericin B-based therapy for cryptococcal meningitis in Thailand and South Africa. Methods:Study protocols required four lumbar punctures with measurements of opening pressure over the first 2 weeks of treatment and additional lumbar punctures if opening pressure raised. Fungal burden and clearance, CSF immune parameters, CD4 cell count, neurological symptoms and signs, and outcome at 2 and 10 weeks were compared between groups categorized by opening pressure at cryptococcal meningitis diagnosis. Results:Patients with higher baseline fungal burden had higher baseline opening pressure. High fungal burden appeared necessary but not sufficient for development of high pressure. Baseline opening pressure was not associated with CD4 cell count, CSF pro-inflammatory cytokines, or altered mental status. Day 14 opening pressure was associated with day 14 fungal burden. Overall mortality was 12% (20/162) at 2 weeks and 26% (42/160) at 10 weeks, with no significant differences between opening pressure groups. Conclusion:Studies are needed to define factors, in addition to fungal burden, associated with raised opening pressure. Aggressive management of raised opening pressure through repeated CSF drainage appeared to prevent any adverse impact of raised opening pressure on outcome in patients with cryptococcal meningitis. The results support increasing access to manometers in resource-poor settings and routine management of opening pressure in patients with cryptococcal meningitis.

Pharmacokinetic interactions between efavirenz and rifampicin in the treatment of HIV and tuberculosis: one size does not fit all.

The concomitant treatment of HIV–tuberculosis co-infection is complicated by pharmacological interactions between drugs, resulting in unpredictable drug levels. We monitored efavirenz levels in all tuberculosis–HIV-treated patients over 2 years. Using 800 mg/day of efavirenz, high levels and toxicity were detected in seven out of nine patients, necessitating reduction or discontinuation. Polymorphisms in cytochrome P450 2B6 may account for this. Therapeutic drug monitoring, dose reduction or a lower starting dose may be appropriate in some patients to abrogate toxicity.

Efficient phagocytosis and laccase activity affect the outcome of HIV-associated cryptococcosis

BACKGROUND Cryptococcal meningitis (CM) is a leading cause of HIV-associated mortality globally. High fungal burden in cerebrospinal fluid (CSF) at diagnosis and poor fungal clearance during treatment are recognized adverse prognostic markers; however, the underlying pathogenic factors that drive these clinical manifestations are incompletely understood. We profiled a large set of clinical isolates for established cryptococcal virulence traits to evaluate the contribution of C. neoformans phenotypic diversity to clinical presentation and outcome in human cryptococcosis. METHODS Sixty-five C. neoformans isolates from clinical trial patients with matched clinical data were assayed in vitro to determine murine macrophage uptake, intracellular proliferation rate (IPR), capsule induction, and laccase activity. Analysis of the correlation between prognostic clinical and host immune parameters and fungal phenotypes was performed using Spearmans r, while the fungal-dependent impact on long-term survival was determined by Cox regression analysis. RESULTS High levels of fungal uptake by macrophages in vitro, but not the IPR, were associated with CSF fungal burden (r = 0.38, P = 0.002) and long-term patient survival (hazard ratio [HR] 2.6, 95% CI 1.2-5.5, P = 0.012). High-uptake strains were hypocapsular (r = -0.28, P = 0.05) and exhibited enhanced laccase activity (r = 0.36, P = 0.003). Fungal isolates with greater laccase activity exhibited heightened survival ex vivo in purified CSF (r = 0.49, P < 0.0001) and resistance to clearance following patient antifungal treatment (r = 0.39, P = 0.003). CONCLUSION These findings underscore the contribution of cryptococcal-phagocyte interactions and laccase-dependent melanin pathways to human clinical presentation and outcome. Furthermore, characterization of fungal-specific pathways that drive clinical manifestation provide potential targets for the development of therapeutics and the management of CM. FUNDING This work was made possible by funding from the Wellcome Trust (WT088148MF), the Medical Research Council (MR/J008176/1), the NIHR Surgical Reconstruction and Microbiology Research Centre and the Lister Institute for Preventive Medicine (to R.C. May), and a Wellcome Trust Intermediate fellowship (089966, to T. Bicanic). The C. neoformans isolates were collected within clinical trials funded by the British Infection Society (fellowship to T. Bicanic), the Wellcome Trust (research training fellowships WT069991, to A.E. Brouwer and WT081794, to J.N. Jarvis), and the Medical Research Council, United Kingdom (76201). The funding sources had no role in the design or conduct of this study, nor in preparation of the manuscript.

Outcomes of cryptococcal meningitis in antiretroviral naïve and experienced patients in South Africa

Cryptococcal meningitis (CM) is a major cause of mortality in HIV-infected patients in much of the world, causing an estimated 504,000 deaths annually in sub-Saharan Africa alone (1). Despite rapid scale-up of antiretroviral therapy (ART) coverage in South Africa, the burden of CM is still high, because ART coverage is barely keeping pace with the number of new HIV-infected patients developing stage IV disease (2). As access to ART expands, increasing numbers of patients are presenting with CM after initiating ART, and CM has emerged as a major cause of morbidity and mortality in African ART programmes (3). Little data is available regarding the presentation and clinical features of CM in patients on ART, and evidence is conflicting on whether short-term outcomes are better in those already on ART at presentation when compared to ART-naive patients (4-6). We therefore examined these issues in a cohort of patients presenting with CM in Cape Town. The study was performed at GF Jooste Hospital, a public-sector adult referral hospital serving a population of 1.3 million. Cryptococcus is the commonest cause of meningitis at the hospital, accounting for 63% of microbiologically confirmed cases (7). All patients presenting with laboratory confirmed CM between 1st January 2007 and 31st December 2008 were prospectively identified, and clinical and laboratory data were collected with approval from the Research Ethics Committee of the University of Cape Town. Patients were classified according to whether they were taking ART at initial presentation, and the primary end-point of in-hospital mortality was recorded for all patients. During the study period the initial treatment of CM consisted of two weeks of induction therapy with amphotericin B (1mg/kg), followed by fluconazole 400mg daily for 8 weeks. As part of ongoing clinical studies 71 patients received additional induction treatment, all of whom were ART naive (61 received flucytosine, 39 received IFNγ, and 8 received fluconazole, all with amphotericin B). Statistical comparisons were made using the Kruskal-Wallis, χ2 or Fishers exact tests. Odds ratios (OR) with 95% confidence intervals (CI) were calculated using logistic regression modeling adjusting for potential confounders (variables were included in the logistic regression model if they were significantly associated with the primary outcome in bivariate analysis (p<0.05) or if they were deemed clinically relevant based on previous reports). During the 2-year period there were 301 episodes of CM, of which 69 were relapses (described in detail elsewhere (8)), and 2 were in HIV-negative patients, leaving 230 HIV-positive patients admitted with a first episode of CM. ART status was unknown in 2 patients, who were excluded from the analysis. Of the remainder, 80% (183) were ART-naive and 20% (45) were on ART at presentation. Median time from ART initiation to presentation with CM was 41 days (IQR 18-87). Demographic and clinical features were similar in ART-naive and experienced patients, as were CSF cell counts and biochemistry (table 1). ART-experienced patients had lower fungal burdens, as evidenced by the lower proportion of India-ink positivity (56% vs 72%, p=0.03), and fewer had abnormal mental status (31% vs 47%, p=0.05). Median duration of hospitalization was 15 days (IQR 13-20 days). In-hospital mortality was 29% in ART-experienced patients, versus 31% in ART-naive patients (p=0.77), with a median time to death of 10 and 13 days respectively. In a multivariate model including the previously identified potential confounders (6) of sex and concurrent TB treatment, along with adjustment for factors significantly associated with the primary outcome in bivariate analysis (administration of a second agent during induction therapy, OR 0.49, 95%CI 0.3-0.9, p=0.03) the relationship between ART status and in-hospital mortality remained non-significant (OR 0.69, 95%CI 0.3-1.5, p= 0.3). Table 1 Demographic, clinical and laboratory features and outcomes of cryptococcal meningitis in 228 ART-naive and –experienced patients with cryptococal meningitis. A large proportion (20%) of adults with a first episode of HIV-associated CM in our setting are now presenting following ART initiation. Although these patients had favourable prognostic signs (9), with lower fungal burdens and less abnormal neurology, the outcomes were poor; no better than in ART-naive patients in both direct and multivariate comparisons. These results differ from a smaller series of 92 patients from Botswana (6), where although there was no significant difference in acute mortality between ART-experienced (n=26) and naive patients with CM in a direct comparison (8% vs 21%, p=0.2), adjusted multivariate analysis suggested improved in-hospital outcomes (6). In contrast, our results are in keeping with data reported in a previous small series from our hospital (5), which found no difference in acute (10 week) mortality in ART-experienced versus ART-naive with CM (33% vs 38%, p=0.8), or in rates of clearance of Cryptococcus from the CSF in the two groups. However, mortality at 1 year was significantly lower in the ART-experienced group (41% versus 76% p=0.03), suggesting that while ART may not affect outcomes from CM in the acute setting, it leads to a substantial reduction in mortality by rapidly reducing susceptibility to other opportunistic infections (5). This is supported by data from a study comparing outcomes of CM in the pre- and post-ART eras in France (4). Although acute mortality remained unchanged following introduction of ART (18% vs 21%), long-term outcomes were markedly improved. It has been suggested that patients developing CM shortly after ART initiation may develop a more inflammatory “unmasking” disease phenotype as cellular immune function is restored; a form of the immune reconstitution inflammatory syndrome (IRIS) (10). While there was evidence that the ART-experienced patients did have lower fungal burdens at presentation, and CM occurred shortly following ART initiation in most cases, few other differences in either clinical or laboratory findings were noted to support this, and there was no evidence of increased CSF cellularity. Further immunological and pathological studies are needed to understand the causes of high mortality in this group, which is in contrast to patients who develop a relapse, or “paradoxical”, CM-IRIS, who tend to have higher CD4 cell counts, less severe disease, and a lower in-patient mortality of 13% (8). The proportion of patients presenting with CM following ART initiation is likely to increase as the global ART roll-out continues. Our data shows that these patients present with severe disease, and have a high acute mortality. This highlights the importance of ongoing efforts to develop and implement preventative strategies. The majority of these cases present within the first few months following ART initiation, and could potentially be prevented through cryptococcal antigen screening at ART initiation with pre-emptive therapy for those testing antigen positive (11).

Cryptococcal immune reconstitution inflammatory syndrome.

Purpose of review The epidemiology and pathogenesis of, and risk factors for, cryptococcal immune reconstitution inflammatory syndrome (CM-IRIS) are reviewed with an emphasis on how new insights inform a rational management approach and prevention strategies. Recent findings Risk factors for paradoxical CM-IRIS are a low inflammatory response and CD4 cell count at baseline, rapid immune restoration from this low baseline, and a high organism or antigen load at baseline and at antiretroviral therapy (ART) initiation. Detailed immune mechanisms are still unclear. Rapidly fungicidal induction therapy, allowing prompt initiation of ART (from around 3 weeks in resource-limited settings in the context of amphotericin B induction) at a time when organism and antigen loads are low, may reduce overall mortality without exacerbating paradoxical CM-IRIS, compared with initiation of ART at later time points. Recent cohorts suggest early recognition and management can reduce the mortality associated with paradoxical CM-IRIS. Unmasking CM-IRIS is preventable through screening for cryptococcal antigen prior to ART and preemptive antifungal treatment for those testing positive, although prospective studies are needed. Summary Optimal antifungal induction and judicious ART timing, together with early recognition and management of developing cases, with thorough exclusion of alternative diagnoses, should help reduce paradoxical CM-IRIS-related mortality. Unmasking CM-IRIS cases should be preventable.

Histopathology of the arachnoid granulations and brain in HIV-associated cryptococcal meningitis: correlation with cerebrospinal fluid pressure.

Objective:To investigate the histopathology of the arachnoid granulations in patients with HIV-associated cryptococcal meningitis and correlate the findings with clinical data, in particular cerebrospinal fluid (CSF) opening pressure. Design:Case series. Methods:Postmortems were requested on patients dying during initial hospitalization with HIV-associated cryptococcal meningitis. Results:Five postmortems were performed. Large numbers of cryptococcal cells were seen within the arachnoid granulations. The number of fungal cells correlated with CSF pressure. Inflammatory cell infiltrates and disruption of the normal architecture of the granulations were also observed. Conclusion:The study provides the first direct evidence supporting the obstruction to CSF reabsorption at the level of the arachnoid granulations as the main mechanism underlying the development of raised CSF pressure in HIV-associated cryptococcal meningitis.

Testing but not treating: missed opportunities and lost lives in the South African antiretroviral therapy programme.

Recently published WHO guidance recommends starting ART in HIV-infected adults with CD4 counts of ≤350 cells/μl [1]. There is mounting evidence that such a policy will lead to lower mortality among HIV-infected individuals [2]. Also modeling data suggests that expanded testing and earlier treatment will reduce HIV transmission [3]. In South Africa ART coverage is not meeting current needs, even using the CD4 count criteria of <200 cells/μl, and mortality early in ART programmes is high due to advanced immunosuppression at initiation [4]. Fortunately, following limited government leadership around HIV in the past, South African President Jacob Zuma has encouraged widespread HIV testing, and announced that he will undertake an HIV test [5].

The burden of HIV-associated cryptococcal disease.

In this issue Park et al. from the Centers for Disease Control University of Alabama and Johannesburg South Africa have made the first attempt to estimate the global burden of HIV-associated cryptococcal infection. As clearly stated by the authors the estimates are exactly that -estimates which rely on the quality of the data on which they are based. Nevertheless the results are striking especially for sub-Saharan Africa where the estimated number of deaths associated with cryptococcal disease at half a million per year is comparable with the number attributed to tuberculosis a much more frequent infection but one for which we have much more effective and widely available therapy. So are these results credible? The data are sparse with just three incidence studies driving the estimates for sub- Saharan Africa (ruling out the possibility of evaluating or taking account of possible intraregional differences in incidence); and the reported incidences are variable resulting in wide ranges for the estimates of cases and associated deaths. However biases are as possible on the downside as on the upside. As the authors acknowledge the relatively low incidence estimate from a South African study with which some of the same authors were involved was likely affected by incomplete case ascertainment. (excerpt)