HIV-Associated Cryptococcal Meningitis Occurring at Relatively Higher CD4 Counts

Neurological Complications Caused by Human Immunodeficiency Virus (HIV) and Associated Opportunistic Co-infections: A Review on their Diagnosis and Therapeutic Insights

Neurocognitive disorders associated with human immunodeficiency virus (HIV) infected individuals increase the risk of mortality and morbidity that remain a prevalent clinical complication even in the antiretroviral therapy era. It is estimated that a considerable number of people in the HIV community are developing neurological complications at their early stages of infection. The daily lives of people with chronic HIV infections are greatly affected by cognitive declines such as loss of attention, learning, and executive functions, and other adverse conditions like neuronal injury and dementia. It has been found that the entry of HIV into the brain and subsequently crossing the blood-brain barrier (BBB) causes brain cell damage, which is the prerequisite for the development of neurocognitive disorders. Besides the HIV replication in the central nervous system and the adverse effects of antiretroviral therapy on the BBB, a range of opportunistic infections, including viral, bacterial, and parasitic agents, augment the neurological complications in people living with HIV (PLHIV). Given the immuno-compromised state of PLHIV, these co-infections can present a wide range of clinical syndromes with atypical manifestations that pose challenges in diagnosis and clinical management, representing a substantial burden for the public health system. Therefore, the present review narrates the neurological complications triggered by HIV and their diagnosis and treatment options. Moreover, coinfections that are known to cause neurological disorders in HIV infected individuals are highlighted.

Utility of Cerebrospinal Fluid Protein Levels as a Potential Predictive Biomarker of Disease Severity in HIV-Associated Cryptococcal Meningitis

Background

Cerebrospinal fluid (CSF) protein levels exhibit high variability in HIV-associated cryptococcal meningitis from being normal to markedly elevated. However, the clinical implications of CSF protein levels in cryptococcal meningitis remain unclear.

Methods

We analysed data from 890 adults with HIV-associated cryptococcal meningitis randomized into two clinical trials in Uganda between 2015 and 2021. CSF protein was grouped into ≥100 mg/dL (n=249) and <100 mg/dL (n=641). We described baseline clinical variables and mortality by CSF protein levels.

Results

Approximately one-third of individuals had a baseline CSF protein ≥100 mg/dL. Those with CSF protein ≥100 mg/dL were more likely to present with Glasgow coma scale scores <15 (P<0.01), self-reported seizures at baseline (P=0.02), higher CD4 T-cells (p<0.001), and higher CSF white cells (p<0.001). Moreover, those with a baseline CSF protein ≥100 mg/dL also had a lower baseline CSF fungal burden (p<0.001) and a higher percentage of sterile CSF cultures at day 14 (p=0.02). Individuals with CSF protein ≥100 mg/dL demonstrated a more pronounced immune response consisting of upregulation of immune effector molecules pro-inflammatory cytokines, type-1 T-helper cell cytokines, type-3 chemokines, and immune-exhaustion marker (p<0.05). 18-week mortality risk in individuals with a CSF protein <100 mg/dL was 34% higher, (unadjusted Hazard Ratio 1.34; 95% CI, 1.05 to 1.70; p=0.02) than those with ≥100 mg/dL.

Conclusion

In cryptococcal meningitis, individuals with CSF protein ≥100 mg/dL more frequently presented with seizures, altered mental status, immune activation, and favourable fungal outcomes. Baseline CSF protein levels may serve as a surrogate marker of immune activation and prognosis.

Baseline Cytomegalovirus Viremia at Cryptococcal Meningitis Diagnosis Is Associated With Long-term Increased Incident TB Disease and Mortality in a Prospective Cohort of Ugandan Adults With HIV

Background

Adults with HIV-associated cryptococcal meningitis have overlapping burdens of cytomegalovirus (CMV) and tuberculosis (TB) coinfections. CMV infection/reactivation is strongly associated with CMV-specific memory T-cell activation and upregulation of type 1 interferons, which may lead to increased risk of TB disease and poor outcomes.

Methods

We conducted a cohort study of 2-week survivors of cryptococcal meningitis during 2010-2021 to determine TB incidence and all-cause mortality over time stratified by baseline CMV status.

Results

We followed 497 Ugandans with HIV-associated cryptococcal meningitis for a median (interquartile range) of 4.6 (2.6-53.9) months. Overall, 42% (210/497) developed incident TB disease or died. One-fifth (98/497, 19.7%) developed incident TB disease, and 29% (142/497) of participants died during follow-up. Of 259 participants with CMV viral load measured at baseline, 37% (96/259) had concurrent CMV viremia (defined as anyone with detectable CMV DNA in plasma/serum by qualitative polymerase chain reaction [PCR] detection). Of 59 with measured CMV immunoglobulin G (IgG), 100% had positive CMV IgG antibody serology (≥10 enzyme-linked immunosorbent assay units/mL). CMV viremia was positively associated with higher HIV viral load (196 667 vs 73 295 copies/mL; P = .002) and higher cerebrospinal fluid fungal burden (68 500 vs 14 000 cfu/mL; P = .002) compared with those without. Participants with high-level CMV viremia (defined as CMV viral load ≥1000 IU/mL) had twice the risk of incident TB (subdistribution adjusted hazard ratio [aHR], 2.18; 95% CI, 1.11-4.27) and death (aHR, 1.99; 95% CI, 1.14-3.49) compared with participants with no or low-level CMV viremia. There was no association between the CMV IgG index and the incidence of TB/death (P = .75).

Conclusions

CMV viremia >1000 IU/mL at meningitis diagnosis was associated with increased incident TB disease and mortality during long-term follow-up. Future studies to determine the causal relationship and potential for therapeutic intervention are warranted.

Early Antiretroviral Therapy Not Associated With Higher Cryptococcal Meningitis Mortality in People With Human Immunodeficiency Virus in High-Income Countries: An International Collaborative Cohort Study

BACKGROUND

Randomized controlled trials (RCTs) from low- and middle-income settings suggested that early initiation of antiretroviral therapy (ART) leads to higher mortality rates among people with HIV (PWH) who present with cryptococcal meningitis (CM). There is limited information about the impact of ART timing on mortality rates in similar people in high-income settings.

METHODS

Data on ART-naive PWH with CM diagnosed from 1994 to 2012 from Europe/North America were pooled from the COHERE, NA-ACCORD, and CNICS HIV cohort collaborations. Follow-up was considered to span from the date of CM diagnosis to earliest of the following: death, last follow-up, or 6 months. We used marginal structural models to mimic an RCT comparing the effects of early (within 14 days of CM) and late (14-56 days after CM) ART on all-cause mortality, adjusting for potential confounders.

RESULTS

Of 190 participants identified, 33 (17%) died within 6 months. At CM diagnosis, their median age (interquartile range) was 38 (33-44) years; the median CD4+ T-cell count, 19/μL (10-56/μL); and median HIV viral load, 5.3 (4.9-5.6) log10 copies/mL. Most participants (n = 157 [83%]) were male, and 145 (76%) started ART. Mimicking an RCT, with 190 people in each group, there were 13 deaths among participants with an early ART regimen and 20 deaths among those with a late ART regimen. The crude and adjusted hazard ratios comparing late with early ART were 1.28 (95% confidence interval, .64-2.56) and 1.40 (.66-2.95), respectively.

CONCLUSIONS

We found little evidence that early ART was associated with higher mortality rates among PWH presenting with CM in high-income settings, although confidence intervals were wide.

Mapping evidence on cryptococcal antigen infection among HIV-infected persons in sub-Saharan Africa- A scoping review protocol

INTRODUCTION

Infections of the central nervous system are a considerable basis of mortality in people living with HIV, with progression to cryptococcal meningitis documented at around 15% of HIV-associated mortality globally, with nearly three-quarters occurring in the sub-Saharan Africa. Discoveries from previous studies prelude to the mortality of cryptococcal antigen positive, which persisted to be elevated than in cryptococcal antigen negative persons. One feasible interpretation of this could be due to undiagnosed cryptococcus. Laboratory investigations identify cryptococcal disease prior to cryptococcal meningitis progression. Point-of-care testing has high sensitivity and specificity as seen with the cryptococcal antigen lateral flow assay screening to expedite treatment. The aim of the study is to map and translate evidence on cryptococcal antigen infection among HIV-infected persons in sub-Saharan Africa.

METHODOLOGY

The proposed scoping review will be conducted using guidelines proposed by Arksey and O'Malley methodological framework and Levac et al. advanced method. It will be guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Scoping Reviews. A comprehensive literature search of studies published from the first relevant publication to 2022 will be conducted on multiple electronic databases. Additional sources (grey literature) will also be searched. The search strategy will be generated and implemented by the principal investigator with assistance from a subject specialist, and an information specialist. Two reviewers will screen eligible studies. The screening will be guided by an inclusion and exclusion criteria. The mixed methods appraisal tool version 2018 will be used to appraise the quality of the empirical studies.

DISCUSSION

The proposed scoping review will map and translate evidence on cryptococcal antigen infection among HIV-infected persons in sub-Saharan Africa. Synthesising and sharing recent evidence in this area has potential to help guide future research and interventions aimed at improving the management of cryptococcal antigen infection among HIV-infected persons in sub-Saharan Africa and other high HIV- burdened settings.

Association of Antibody Immunity With Cryptococcal Antigenemia and Mortality in a South African Cohort With Advanced Human Immunodeficiency Virus Disease

BACKGROUND

Asymptomatic cryptococcal antigenemia (positive blood cryptococcal antigen [CrAg]) is associated with increased mortality in individuals with human immunodeficiency virus (HIV) even after adjusting for CD4 count and despite receiving antifungal treatment. The association of antibody immunity with mortality in adults with HIV with cryptococcal antigenemia is unknown.

METHODS

Cryptococcal capsular glucuronoxylomannan (GXM)- and naturally occurring β-glucans (laminarin, curdlan)-binding antibodies were measured in blood samples of 197 South Africans with HIV who underwent CrAg screening and were followed up to 6 months. Associations between antibody titers, CrAg status, and all-cause mortality were sought using logistic and Cox regression, respectively.

RESULTS

Compared with CrAg-negative individuals (n = 130), CrAg-positive individuals (n = 67) had significantly higher IgG1 (median, 6672; interquartile range [IQR], 4696-10 414 vs 5343, 3808-7722 μg/mL; P = .007), IgG2 (1467, 813-2607 vs 1036, 519-2012 μg/mL; P = .01), and GXM-IgG (1:170, 61-412 vs 1:117, 47-176; P = .0009) and lower curdlan-IgG (1:47, 11-133 vs 1:93, 40-206; P = .01) titers. GXM-IgG was associated directly with cryptococcal antigenemia adjusted for CD4 count and antiretroviral therapy use (odds ratio, 1.64; 95% confidence interval [CI], 1.21 to 2.22). Among CrAg-positive individuals, GXM-IgG was inversely associated with mortality at 6 months adjusted for CD4 count and tuberculosis (hazard ratio, 0.50; 95% CI, .33 to .77).

CONCLUSIONS

The inverse association of GXM-IgG with mortality in CrAg-positive individuals suggests that GXM-IgG titer may have prognostic value in those individuals. Prospective longitudinal studies to investigate this hypothesis and identify mechanisms by which antibody may protect against mortality are warranted.

Prevalence and Associated Factors of Cryptococcal Antigenemia in HIV-Infected Patients with CD4 < 200 Cells/µL in São Paulo, Brazil: A Bayesian Analysis

Cryptococcosis is a severe life-threatening disease and a major cause of mortality in people with advanced AIDS and CD4 ≤ 100 cells/µL. Considering the knowledge gap regarding the benefits of routine application of antigenemia tests in HIV-infected patients with 100−200 CD4 cells/µL for the prevention of cryptococcal meningitis (CM), we aimed to evaluate the prevalence of positive antigenemia through lateral flow assay (LFA) and associated factors in HIV-infected patients with CD4 < 200 cells/µL. Our findings of 3.49% of positive LFA (LFA+) patients with CD4 < 100 cells/µL and 2.24% with CD4 between 100−200 cells/µL have been included in a Bayesian analysis with 12 other studies containing similar samples worldwide. This analysis showed a proportion of 3.6% LFA+ patients (95% credible interval-Ci [2.5−5.7%]) with CD4 < 100 cells/µL and 1.1% (95%Ci [0.5−4.3%]) with CD4 between 100−200 cells/µL, without statistical difference between these groups. The difference between mortality rates in LFA+ and negative LFA groups was e = 0.05013. Cryptococcoma and CM were observed in the LFA+ group with 100−200 and <100 CD4 cells/µL, respectively. Considering the benefits of antifungal therapy for LFA+ patients, our data reinforced the recommendation to apply LFA as a routine test in patients with 100−200 CD4 cells/µL aiming to expand cost-effectiveness studies in this group.

Comparative miRNA transcriptomics of macaques and mice reveals MYOC is an inhibitor for Cryptococcus neoformans invasion into the brain

Cryptococcal meningoencephalitis (CM) is emerging as an infection in HIV/AIDS patients shifted from primarily ART­naive to ART-experienced individuals, as well as patients with COVID-19 and immunocompetent hosts. This fungal infection is mainly caused by the opportunistic human pathogen Cryptococcus neoformans. Brain or central nervous system (CNS) dissemination is the deadliest process for this disease; however, mechanisms underlying this process have yet to be elucidated. Moreover, illustrations of clinically relevant responses in cryptococcosis are currently limited due to the low availability of clinical samples. In this study, to explore the clinically relevant responses during C. neoformans infection, macaque and mouse infection models were employed and miRNA-mRNA transcriptomes were performed and combined, which revealed cytoskeleton, a major feature of HIV/AIDS patients, was a centric pathway regulated in both infection models. Notably, assays of clinical immune cells confirmed an enhanced macrophage “Trojan Horse” in patients with HIV/AIDS, which could be shut down by cytoskeleton inhibitors. Furthermore, myocilin, encoded by MYOC, was found to be a novel enhancer for the macrophage “Trojan Horse,” and an enhanced fungal burden was achieved in the brains of MYOC-transgenic mice. Taken together, the findings from this study reveal fundamental roles of the cytoskeleton and MYOC in fungal CNS dissemination, which not only helps to understand the high prevalence of CM in HIV/AIDS but also facilitates the development of novel therapeutics for meningoencephalitis caused by C. neoformans and other pathogenic microorganisms.

A secondary analysis of depression outcomes from a randomized controlled trial of adjunctive sertraline for HIV-associated cryptococcal meningitis

Background: Depression is a risk factor for worse HIV outcomes in persons living with HIV/AIDS, including engagement-in-care, HIV medication adherence, and retention-in-care. Depression has a prevalence of more than three times as high as in the general population. Despite this, there are few randomized studies of antidepressants in HIV-infected Africans, including those with opportunistic infections. Methods: We enrolled 460 HIV-infected Ugandans with cryptococcal meningitis into a randomized clinical trial of adjunctive sertraline vs placebo (2015-2017). We defined depression using the Center for Epidemiologic Studies Depression Scale (CES-D) score of >15, and severe depression as >26 at one and three months after meningitis diagnosis and initiation of treatment. We evaluated the relationship between sertraline and depression, as well as associations with persistent depression, at three months. Results: At one- and three-months post meningitis diagnosis, 62% (108/174) and 44% (74/169) of all subjects had depression (CES>15), respectively. At three months, sertraline-treated subjects had consistent risk for depression as placebo-treated subjects but were significantly less likely to have severe depression (CES>26) (OR 0.335; 95%CI, 0.130-0.865). Of those with depression at one month, sertraline-treated subjects were less likely than placebo-treated subjects to be depressed at three months (p=0.05). Sertraline was the only factor we found significant in predicting persistent depression at three months among those with depression at one month. Conclusions: Depression is highly prevalent in HIV-infected persons who have survived cryptococcal meningitis. We found that sertraline is associated with a modest reduction in depression in those with depression at baseline and a significant decrease in severe depression.

Cytomegalovirus viremia as a risk factor for mortality in HIV-associated cryptococcal and tuberculous meningitis

OBJECTIVES

Cytomegalovirus (CMV) viremia is associated with increased mortality in persons with HIV. We previously demonstrated that CMV viremia was a risk factor for 10-week mortality in antiretroviral therapy (ART)-naïve persons with cryptococcal meningitis. We investigated whether similar observations existed over a broader cohort of HIV-associated meningitis at 18 weeks.

METHODS

We prospectively enrolled Ugandans with cryptococcal or tuberculous (TB) meningitis into clinical trials during 2015-2019. We quantified CMV DNA concentrations from stored baseline plasma or serum samples from 340 participants. We compared 18-week survival between those with and without CMV viremia.

RESULTS

We included 308 persons with cryptococcal meningitis and 32 with TB meningitis, of whom 121 (36%) had detectable CMV DNA. Baseline CD4⁺ T cell counts (14 vs. 24 cells/µL; P=0.07) and antiretroviral exposure (47% vs. 45%; P=0.68) did not differ between CMV viremic and non-viremic persons, respectively. The 18-week mortality was 50% (61/121) in those with CMV viremia versus 34% (74/219) in those without (P=0.003). Any detectable CMV viremia (aHR=1.60; 95%CI, 1.13-2.25; P=0.008) and greater viral load (aHR=1.22 per log₁₀ IU/mL increase; 95%CI, 1.09-1.35; P<0.001) were positively associated with all-cause mortality through 18 weeks.

CONCLUSIONS

CMV viremia at baseline was associated with a higher risk of death at 18 weeks among persons with HIV-associated cryptococcal or TB meningitis, and the risk increased as the CMV viral load increased. Further investigation is warranted to determine if CMV is a modifiable risk contributing to deaths in HIV-associated meningitis, versus its presence representing a biomarker of immune dysfunction.

Cryptococcus neoformans Infection Induces IL-17 Production by Promoting STAT3 Phosphorylation in CD4+ T Cells

Cryptococcus neoformans infection in the central nervous system is a severe infectious disease with poor outcomes and high mortality. It has been estimated that there are 220,000 new cases each year. Over 90% of C. neoformans meningitis cases were diagnosed in AIDS patients with CD4⁺ T cell count <100 cells/μl; however, the mechanism of cryptococcal meningitis in patients with normal immune functions remains unclear. IL-17 is a pro-inflammatory cytokine and plays an important role in anti-fungal immunity. Here we report that significantly high levels of IL-17 were predominantly detected in the cerebrospinal fluid of patients with either AIDS- or non-AIDS-associated C. neoformans meningitis but not in patients with tuberculous meningitis or non-neurosyphilis. Antifungal therapy minimized the IL-17 level in the cerebrospinal fluid. An in vitro mechanistic study showed that C. neoformans stimulation of healthy peripheral blood mononuclear cells prompted IL-17 production, and CD4⁺ T cells were the predominant IL-17-producing cells. IL-17 production by C. neoformans stimulation was STAT3 signaling dependent. Inhibition of STAT3 phosphorylation attenuated the C. neoformans-mediated IL-17 expression. Our data highlighted the significance of CD4⁺ T cells in antifungal immunity and suggested IL-17 as a diagnostic biomarker of C. neoformans infection and STAT3 as a checkpoint for antifungal targeted therapies.

Cost-effectiveness of cryptococcal antigen screening at CD4 counts of 101-200 cells/µL in Botswana

Background: Cryptococcal antigen (CrAg) screening in individuals with advanced HIV reduces cryptococcal meningitis (CM) cases and deaths. The World Health Organization recently recommended increasing screening thresholds from CD4 ≤100 cells/µL to ≤200 cells/µL. CrAg screening at CD4 ≤100 cells/µL is cost-effective; however, the cost-effectiveness of screening patients with CD4 101-200 cells/µL requires evaluation. Methods: Using a decision analytic model with Botswana-specific cost and clinical estimates, we evaluated CrAg screening and treatment among individuals with CD4 counts of 101-200 cells/µL. We estimated the number of CM cases and deaths nationally and treatment costs without screening. For screening we modeled the number of CrAg tests performed, number of CrAg-positive patients identified, proportion started on pre-emptive fluconazole, CM cases and deaths. Screening and treatment costs were estimated and cost per death averted or disability-adjusted life year (DALY) saved compared with no screening. Results: Without screening, we estimated 142 CM cases and 85 deaths annually among individuals with CD4 101-200 cells/µL, with treatment costs of $368,982. With CrAg screening, an estimated 33,036 CrAg tests are performed, and 48 deaths avoided (1,017 DALYs saved).  While CrAg screening costs an additional $155,601, overall treatment costs fall by $39,600 (preemptive and hospital-based CM treatment), yielding a net increase of $116,001. Compared to no screening, high coverage of CrAg screening and pre-emptive treatment for CrAg-positive individuals in this population avoids one death for $2440 and $114 per DALY saved. In sensitivity analyses assuming a higher proportion of antiretroviral therapy (ART)-naïve patients (75% versus 15%), cost per death averted was $1472; $69 per DALY saved. Conclusions: CrAg screening for individuals with CD4 101-200 cells/µL was estimated to have a modest impact, involve additional costs, and be less cost-effective than screening populations with CD4 counts ≤100 cells/µL. Additional CrAg screening costs must be considered against other health system priorities.

Harnessing the Potential of Multiomics Studies for Precision Medicine in Infectious Disease

The field of infectious diseases currently takes a reactive approach and treats infections as they present in patients. Although certain populations are known to be at greater risk of developing infection (eg, immunocompromised), we lack a systems approach to define the true risk of future infection for a patient. Guided by impressive gains in "omics" technologies, future strategies to infectious diseases should take a precision approach to infection through identification of patients at intermediate and high-risk of infection and deploy targeted preventative measures (ie, prophylaxis). The advances of high-throughput immune profiling by multiomics approaches (ie, transcriptomics, epigenomics, metabolomics, proteomics) hold the promise to identify patients at increased risk of infection and enable risk-stratifying approaches to be applied in the clinic. Integration of patient-specific data using machine learning improves the effectiveness of prediction, providing the necessary technologies needed to propel the field of infectious diseases medicine into the era of personalized medicine.

Symptomatic Cryptococcal Meningitis with Negative Serum and Cerebrospinal Fluid Cryptococcal Antigen Tests

Background

Cryptococcal meningitis is a leading cause of mortality in advanced HIV disease. A positive cerebrospinal fluid cryptococcal antigen (CrAg) test defines cryptococcal meningitis. Herein, we present a patient with serum and cerebrospinal fluid CrAg negative cryptococcal meningitis, despite a positive cerebrospinal fluid India ink examination and quantitative culture.

Case Details

A 56-year-old HIV-positive Ugandan woman, with an undetectable HIV RNA viral load and CD4+ T-cell count of 766 cells per microlitre presented with signs and symptoms consistent with cryptococcal meningitis. Her serum and cerebrospinal fluid CrAg tests were negative despite having a positive cerebrospinal fluid India ink and quantitative culture. On day 1, she was commenced on intravenous amphotericin B deoxycholate (1mg/kg) for 3 days (considering 10 CFU growth of Cryptococcus spp) in combination with oral flucytosine (100mg/kg) for 7 days and then fluconazole 1200mg once daily for the next 11 days. By day 7, she was symptom free and quantitative cerebrospinal fluid culture was negative for Cryptococcus spp. She was discharged on day 9. At 10 weeks (day +40) and 18 weeks (day +72), she was well and adherent to her antiretroviral therapy and on maintenance phase of cryptococcal meningitis on fluconazole at a dose of 400mg once daily.

Conclusion

This report alerts clinicians managing patients with HIV-associated cryptococcal meningitis to four uncommon clinical scenarios; first, the possibility of negative serum and cerebrospinal fluid CrAg lateral flow assay results in the context of low cerebrospinal fluid fungal burden in a symptomatic patient. Second, possible occurrence of cryptococcal meningitis in a patient with high CD4 T-cell lymphocyte counts. Third, an early seroconversion of cryptococcal antigenaemia following effective fluconazole therapy. Fourth, an early symptomatic relapse of cryptococcal meningitis albeit negative serum CrAg.

Establishment of a novel scoring model for mortality risk prediction in HIV-infected patients with cryptococcal meningitis

Background

Cryptococcal meningitis (CM) remains a leading cause of death in HIV-infected patients, despite advances in CM diagnostic and therapeutic strategies. This study was performed with the aim to develop and validate a novel scoring model to predict mortality risk in HIV-infected patients with CM (HIV/CM).

Methods

Data on HIV/CM inpatients were obtained from a Multicenter Cohort study in China. Independent risk factors associated with mortality were identified based on data from 2013 to 2017, and a novel scoring model for mortality risk prediction was established. The bootstrapping statistical method was used for internal validation. External validation was performed using data from 2018 to 2020.

Results

We found that six predictors, including age, stiff neck, impaired consciousness, intracranial pressure, CD4⁺ T-cell count, and urea levels, were associated with poor prognosis in HIV/CM patients. The novel scoring model could effectively identify HIV/CM patients at high risk of death on admission (area under curve 0.876; p<0.001). When the cut-off value of 5.5 points or more was applied, the sensitivity and specificity was 74.1 and 83.8%, respectively. Our scoring model showed a good discriminatory ability, with an area under the curve of 0.879 for internal validation via bootstrapping, and an area under the curve of 0.886 for external validation.

Conclusions

Our developed scoring model of six variables is simple, convenient, and accurate for screening high-risk patients with HIV/CM, which may be a useful tool for physicians to assess prognosis in HIV/CM inpatients.

Impact of biological sex on cryptococcal meningitis mortality in Uganda and South Africa

The role of biological sex on clinical outcomes and the pathogenesis of AIDS-related opportunistic infections is unknown. We assessed baseline biomarkers and outcomes between 577 men and 400 women in HIV-related cryptococcal meningitis cohorts in Uganda and South Africa from 2010 to 2017. We compared 10-week mortality by sex via Cox proportional hazards models. The 10-week mortality for women was 50% (198/400) and 43% (247/577) for men. Women had higher risk of death in an unadjusted model (Hazard Ratio (HR) = 1.20; 95%CI, 1.00-1.45; P = .05). Women maintained a higher risk when adjusting for quantitative CSF culture, altered mental status, CSF pleocytosis, age, and antiretroviral status (HR = 1.31; 95%CI, 1.07-1.59; P < .01). However, after adjusting for hemoglobin, the risk of death did not differ between women and men (HR = 1.17; 95%CI, 0.94-1.45; P = .17). Moderate to severe anemia (hemoglobin < 8.5 g/dL) was present among 16% (55/355) of women and 10% (55/532) of men (P = .02). Of the 373 participants with CSF biomarkers, men had higher median pro- and anti-inflammatory, monocyte/macrophage differentiation, maturation, and migration, immune exhaustion, and cytotoxicity cytokines than women (P < .05). We identified biological sex as proxy for anemia, a potentially modifiable risk factor for cryptococcal meningitis mortality. Immune response may contribute to the multifaceted underlying mechanisms for the discrepancy in mortality based on sex.

LAY SUMMARY

We examined the role of biological sex in cryptococcal meningitis mortality in a large cohort. Our findings reveal significant differences in inflammatory markers by biological sex. Women have significantly higher mortality due to cryptococcal meningitis that is attributable to anemia at baseline.

Screening for Cryptococcal Antigenemia and Burden of Cryptococcosis at the Time of HIV Diagnosis: A Retrospective Multicenter Study

Introduction

Screening for cryptococcal antigen (CrAg) is recommended for people living with HIV (PLWH) who present with low CD4 lymphocyte counts. Real-world experience is important to identify gaps between the guidelines and clinical practice. We investigated the trends of CrAg testing and prevalence of cryptococcal antigenemia among PLWH at the time of HIV diagnosis and the related mortality in Taiwan from 2009 to 2018.

Methods

Medical records of newly diagnosed PLWH seeking care at six medical centers around Taiwan between 2009 and 2018 were reviewed. The annual trends of PLWH who had CrAg testing and cryptococcal antigenemia were examined by Cochran-Armitage test. Among PLWH with CD4 < 200 cells/µl, timing of CrAg testing was analyzed for association with 12-month all-cause mortality in Kaplan-Meier plots and in a Cox proportional hazards model after adjustments.

Results

Among 5372 included PLWH, 1150 (21.4%) presented with baseline CD4 < 100 cells/µl, and this proportion had decreased during the study period [from 108 (29.3%) in 2009 to 93 (22.3%) in 2018 (P = 0.039)]. The overall prevalence of cryptococcal antigenemia was 7.8% among PLWH with CD4 < 100 cells/µl, which remained stable during the 10-year study period (P = 0.356) and was 2.6% among PLWH with CD4 100–199 cells/µl. The uptake of CrAg testing had increased from 65.7% in 2009 to 78.0% in 2018 (P = 0.002) among PLWH with CD4 < 100 cells/µl. Late CrAg testing, defined by 14 days or later after HIV diagnosis, was associated with increased risk of 12-month mortality compared to early CrAg testing (adjusted hazard ratio 2.028, 95% CI 1.109–3.708).

Conclusions

Burden of cryptococcosis remained high among PLWH with low CD4 lymphocyte counts in Taiwan. Uptake of CrAg screening among late HIV presenters was still suboptimal and delayed. Late CrAg testing was associated with a higher mortality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00451-5.

Clinical characteristics, Cryptococcus neoformans genotypes, antifungal susceptibility, and outcomes in human immunodeficiency virus-positive patients in Beijing, China

Cryptococcus neoformans is an environmental fungal pathogen that causes opportunistic infections and severe disseminated meningoencephalitis, mainly in immunocompromised patients such as those with acquired immunodeficiency syndrome (AIDS). In this study, the clinical characteristics, treatment protocols, and outcomes of 70 patients with AIDS and Cryptococcus neoformans infection at Beijing Ditan Hospital were retrospectively analyzed. We performed antimicrobial sensitivity tests and multilocus sequence typing (MLST) on C. neoformans isolates from these patients. The most common symptoms were headache (58.6%), fever (54.3%), and high cerebrospinal fluid pressure (≥200 mm H₂O) (71.4%). All patients were positive for C. neoformans antigen in blood or cerebrospinal fluid. The CD4 cell counts of 92.8% (65/70) of patients were <100 cells/µL. In total, 74 C. neoformans isolates were obtained from the 70 patients. The 65 isolates that could be typed fell into 12 sequence types (STs) by MLST: ST5, ST31, ST63, ST202, ST237, ST289, ST295, ST296, ST298, ST324, ST337, and ST359. ST5 was the major type, accounting for 78.5% of isolates (51/65). This study comprehensively assessed the clinical and molecular epidemiology of C. neoformans in patients with AIDS and may inform the development of targeted prevention and treatment strategies for immunocompromised patients with C. neoformans infection.

Outcomes of Reflex Cryptococcal Antigen (CrAg) Screening in Human Immunodeficiency Virus (HIV)-Positive Patients With CD4 Counts of 100-200 Cells/µL in Botswana

Increasing the CD4-count threshold for cryptococcal antigen (CrAg) screening from ≤100 to ≤200 cells/µL resulted in a 3-fold increase in numbers screened. CrAg-prevalence was 3.5% at CD4 101-200 and 6.2% ≤100 cells/µL. Six-month mortality was 21.4% (9/42) in CrAg-positive CD4 ≤100 cells/µL and 3.2% (1/31) in CrAg-positive CD4 101-200 cells/µL.

Cerebrospinal Fluid Early Fungicidal Activity as a Surrogate Endpoint for Cryptococcal Meningitis Survival in Clinical Trials

BACKGROUND

In cryptococcal meningitis phase 2 clinical trials, early fungicidal activity (EFA) of Cryptococcus clearance from cerebrospinal fluid (CSF) is used as a surrogate endpoint for all-cause mortality. The Food and Drug Administration allows for using surrogate endpoints for accelerated regulatory approval, but EFA as a surrogate endpoint requires further validation. We examined the relationship between rate of CSF Cryptococcus clearance (EFA) and mortality through 18 weeks.

METHODS

We pooled individual-level CSF data from 3 sequential cryptococcal meningitis clinical trials conducted during 2010-2017. All 738 subjects received amphotericin + fluconazole induction therapy and had serial quantitative CSF cultures. The log10-transformed colony-forming units (CFUs) per mL CSF were analyzed by general linear regression versus day of culture over the first 10 days.

RESULTS

Mortality through 18 weeks was 37% for EFA > = 0.60 (n = 170), 36% for 0.40-0.59 (n = 182), 39% for 0.30-0.39 (n = 112), 35% for 0.20-0.29 (n = 87), and 50% for those with EFA < 0.20 CFU/mL/day (n = 187). The hazard ratio for 18-week mortality, comparing those with EFA < 0.20 to those with EFA > = 0.20, was 1.60 (95% confidence interval, 1.25, 2.04; P = .002). The lowest EFA group had lower median CD4 T-cell counts (P < .01) and lower proportion of patients with CSF pleocytosis (P < .001).

CONCLUSIONS

EFA is associated with all-cause mortality in cryptococcal meningitis. An EFA threshold of > = 0.20 log10 CFU/mL/day was associated with similar 18-week mortality (37%) compared to 50% mortality with EFA < 0.20. This EFA threshold may be considered a target for a surrogate endpoint. This builds upon existing studies to validate EFA as a surrogate endpoint.

Cost-effectiveness of cryptococcal antigen screening at CD4 counts of 101-200 cells/µL in Botswana

Background: Cryptococcal antigen (CrAg) screening in individuals with advanced HIV reduces cryptococcal meningitis (CM) cases and deaths. The World Health Organization recently recommended increasing screening thresholds from CD4 ≤100 cells/µL to ≤200 cells/µL. CrAg screening at CD4 ≤100 cells/µL is cost-effective; however, the cost-effectiveness of screening patients with CD4 101-200 cells/µL requires evaluation. Methods: Using a decision analytic model with Botswana-specific cost and clinical estimates, we evaluated CrAg screening and treatment among individuals with CD4 counts of 101-200 cells/µL. We estimated the number of CM cases and deaths nationally and treatment costs without screening. For screening we modeled the number of CrAg tests performed, number of CrAg-positive patients identified, proportion started on pre-emptive fluconazole, CM cases and deaths. Screening and treatment costs were estimated and cost per death averted or disability-adjusted life year (DALY) saved compared with no screening. Results: Without screening, we estimated 142 CM cases and 85 deaths annually among individuals with CD4 101-200 cells/µL, with treatment costs of $368,982. With CrAg screening, an estimated 33,036 CrAg tests are performed, and 48 deaths avoided (1,017 DALYs saved).  While CrAg screening costs an additional $155,601, overall treatment costs fall by $39,600 (preemptive and hospital-based CM treatment), yielding a net increase of $116,001. Compared to no screening, high coverage of CrAg screening and pre-emptive treatment for CrAg-positive individuals in this population avoids one death for $2440 and $114 per DALY saved. In sensitivity analyses assuming a higher proportion of antiretroviral therapy (ART)-naïve patients (75% versus 15%), cost per death averted was $1472; $69 per DALY saved. Conclusions: CrAg screening for individuals with CD4 101-200 cells/µL was estimated to have a modest impact, involve additional costs, and be less cost-effective than screening populations with CD4 counts ≤100 cells/µL. Additional CrAg screening costs must be considered against other health system priorities.

Unexpected case of cryptococcal meningoencephalitis in a patient with long-standing well-controlled HIV infection

Cryptococcal meningoencephalitis (CM) classically occurs in individuals with advanced HIV infection, solid organ transplants, or other immunocompromising conditions. We report a case of fatal CM in a 78-year-old woman with well-controlled HIV infection who had delayed diagnosis, persistently elevated intracranial pressure and pleocytosis of the cerebrospinal fluid. Initial suspicion for CM was low due to her relatively high CD4⁺ T cell counts, which likely contributed to greater inflammation.

Asymptomatic cryptococcal antigenemia in HIV-infected patients: a review of recent studies

The prevalence of asymptomatic cryptococcal antigenemia (ACA) in human immunodeficiency virus (HIV) infected individuals has been observed to be elevated. The prevalence of ACA ranges from 1.3% to 13%, with different rates of prevalence in various regions of the world. We reviewed studies conducted internationally, and also referred to two established expert consensus guideline documents published in China, and we have concluded that Chinese HIV-infected patients should undergo cryptococcal antigen screening when CD4 T-cell counts fall below 200 cells/μL and that the recommended treatment regimen for these patients follow current World Health Organization guidelines, although it is likely that this recommendation may change in the future. Early screening and optimized preemptive treatment for ACA is likely to help decrease the incidence of cryptococcosis, and is lifesaving. Further studies are warranted to explore issues related to the optimal management of ACA.

Pathogen and host genetics underpinning cryptococcal disease

Cryptococcosis is a severe fungal disease causing 220,000 cases of cryptococcal meningitis yearly. The etiological agents of cryptococcosis are taxonomically grouped into at least two species complexes belonging to the genus Cryptococcus. All of these yeasts are environmentally ubiquitous fungi (often found in soil, leaves and decaying wood, tree hollows, and associated with bird feces especially pigeon guano). Infection in a range of animals including humans begins following inhalation of spores or aerosolized yeasts. Recent advances provide fundamental insights into the factors from both the pathogen and its hosts which influence pathogenesis and disease. The complex interactions leading to disease in mammalian hosts have also updated from the availability of better genomic tools and datasets. In this review, we discuss recent genetic research on Cryptococcus, covering the epidemiology, ecology, and evolution of Cryptococcus pathogenic species. We also discuss the insights into the host immune response obtained from the latest genetic modified host models as well as insights from monogenic disorders in humans. Finally we highlight outstanding questions that can be answered in the near future using bioinformatics and genomic tools.

Tuberculosis in HIV-Associated Cryptococcal Meningitis is Associated with an Increased Risk of Death

Tuberculosis (TB) and cryptococcal meningitis are leading causes of morbidity and mortality in advanced HIV disease. Data are limited on TB co-infection among individuals with cryptococcal meningitis. We performed a retrospective analysis of HIV-infected participants with cryptococcal meningitis from 2010-2017. Baseline demographics were compared between three groups: 'prevalent TB' if TB treated >14 days prior to cryptococcal meningitis diagnosis, 'concurrent TB' if TB treated ± 14 days from diagnosis, or 'No TB at baseline'. We used time-updated proportional-hazards regression models to assess TB diagnosis as a risk for death. Of 870 participants with cryptococcal meningitis, 50 (6%) had prevalent TB, 67 (8%) had concurrent TB, and 753 (86%) had no baseline TB. Among participants without baseline TB, 67 (9%) were diagnosed with incident TB (after >14 days), with a median time to TB incidence of 41 days (IQR, 22-69). The 18-week mortality was 50% (25/50) in prevalent TB, 46% (31/67) in concurrent TB, and 45% (341/753) in the no TB group (p = 0.81). However, TB co-infection was associated with an increased hazard of death (HR = 1.75; 95% CI, 1.33-2.32; p < 0.001) in a time-updated model. TB is commonly diagnosed in cryptococcal meningitis, and the increased mortality associated with co-infection is a public health concern.

Cryptococcal antigenemia is associated with meningitis or death in HIV-infected adults with CD4 100-200 cells/mm3

BACKGROUND

Cryptococcal antigen (CrAg) screening with fluconazole prophylaxis has been shown to prevent cryptococcal meningitis and mortality for people living with HIV (PLWH) with CD4 < 100 cells/mm³. While cryptococcal meningitis occurs in individuals with CD4 100-200 cells/mm³, there is limited evidence that CrAg screening predicts cryptococcal meningitis or mortality among this group with moderate immunosuppression. Current IDSA and WHO clinical guidelines recommend restricting CrAg screening to PLWH with CD4 < 100 cells/mm³.

METHODS

We conducted a prospective cohort study of PLWH 18+ years who had not initiated ART in South Africa. We followed participants for 14 months to determine onset of cryptococcal meningitis or all-cause mortality. At study completion, we retrospectively tested stored serum samples for CrAg using an enzyme immunoassay (EIA). We calculated CD4-stratified incidence rates of outcomes and used Cox proportional hazards to measure associations between CrAg positivity and outcomes.

RESULTS

We enrolled 2383 PLWH, and 1309 participants had serum samples tested by CrAg EIA. The median CD4 was 317 cells/mm³ (interquartile range: 173-491 cells/mm³). By CD4 count at baseline, there were 209 individuals with a CD4 count of 100-200 cells/mm³ and available CrAg test results. Of these, four (1.9%) tested positive. Two of four (IR: 58.8 per 100 person-years) CrAg+ participants and 11 of 205 (IR: 5.6 per 100 person-years) CrAg- participants developed cryptococcal meningitis or died for an overall rate of death or cryptococcal meningitis that was 10.0-times higher for those who were CrAg+ (95% confidence interval: 2.2-45.3). Among those with CD4 < 100 cell/mm³ and CrAg EIA test results (N = 179), ten (5.6%) participants tested CrAg+. Among this group, seven of ten (IR: 137.6 per 100 person-years) CrAg+ participants and 26 of 169 (IR: 17.8 per 100 person-years) CrAg- participants developed cryptococcal meningitis or died, for a rate of death or cryptococcal meningitis that was 6.3-times higher for those who were CrAg+ (95% confidence interval: 2.7-14.6).

CONCLUSIONS

Although few PLWH with moderate immunosuppression screened CrAg positive, a positive CrAg test was predictive of increased risk of cryptococcal meningitis or death. Similar to those with a CD4 < 100 cell/mm³, systematic CrAg screening may reduce morbidity and mortality in PLWH with CD4 100-200 cells/mm³.

Mortality from HIV-associated meningitis in sub-Saharan Africa: a systematic review and meta-analysis

INTRODUCTION

HIV-associated cryptococcal, TB and pneumococcal meningitis are the leading causes of adult meningitis in sub-Saharan Africa (SSA). We performed a systematic review and meta-analysis with the primary aim of estimating mortality from major causes of adult meningitis in routine care settings, and to contrast this with outcomes from clinical trial settings.

METHODS

We searched PubMed, EMBASE and the Cochrane Library for published clinical trials (defined as randomized-controlled trials (RCTs) or investigator-managed prospective cohorts) and observational studies that evaluated outcomes of adult meningitis in SSA from 1 January 1990 through 15 September 2019. We performed random effects modelling to estimate pooled mortality, both in clinical trial and routine care settings. Outcomes were stratified as short-term (in-hospital or two weeks), medium-term (up to 10 weeks) and long-term (up to six months).

RESULTS AND DISCUSSION

Seventy-nine studies met inclusion criteria. In routine care settings, pooled short-term mortality from cryptococcal meningitis was 44% (95% confidence interval (95% CI):39% to 49%, 40 studies), which did not differ between amphotericin (either alone or with fluconazole) and fluconazole-based induction regimens, and was twofold higher than pooled mortality in clinical trials using amphotericin based treatment (21% (95% CI:17% to 25%), 17 studies). Pooled short-term mortality of TB meningitis was 46% (95% CI: 33% to 59%, 11 studies, all routine care). For pneumococcal meningitis, pooled short-term mortality was 54% in routine care settings (95% CI:44% to 64%, nine studies), with similar mortality reported in two included randomized-controlled trials. Few studies evaluated long-term outcomes.

CONCLUSIONS

Mortality rates from HIV-associated meningitis in SSA are very high under routine care conditions. Better strategies are needed to reduce mortality from HIV-associated meningitis in the region.

Unveil the transcriptional landscape at the Cryptococcus-host axis in mice and nonhuman primates

Pathogens and hosts require rapid modulation of virulence and defense mechanisms at the infection axis, but monitoring such modulations is challenging. In studying the human fungal pathogen Cryptococcus neoformans, mouse and rabbit infection models are often employed to shed light on the disease mechanisms but that may not be clinically relevant. In this study, we developed an animal infection model using the non-human primate cynomolgus monkey Macaca fascicularis. In addition, we systematically profiled and compared transcriptional responses between the infected mice and the cynomolgus monkey, using simultaneous or dual RNA next-generation sequencing. We demonstrated that there are shared but distinct transcriptional profiles between the two models following C. neoformans infection. Specifically, genes involved in immune and inflammatory responses are all upregulated. Osteoclastogenesis and insulin signaling are also significantly co-regulated in both models and disrupting an osteoclastogenesis-associated gene (OC-STAMP) or the insulin-signaling process significantly altered the host tolerance to C. neoformans. Moreover, C. neoformans was shown to activate metal sequestration, dampen the sugar metabolism, and control cell morphology during infection. Taking together, we described the development of a non-human primate model of cryptococcosis that allowed us to perform an in-depth analysis and comparison of transcriptome profiles during infections of two animal models and conceptually identify host genes important in disease responses. This study provides new insights in understanding fungal pathogenesis mechanisms that potentially facilitate the identification of novel drug targets for the treatment of cryptococcal infection.

The host-pathogen interaction is highly dynamic and tightly regulated, and yet is difficult to monitor. Traditional investigations provide valuable information for the understanding of pathogenic microbial biology but are time-consuming and often neglect the host immune responses. In addition, current animal models for studying pathogenic fungi are limited in mimicking the responses from humans. The development of a new Cryptococcus neoformans infection model using nonhuman primates and the utilization of simultaneous RNA sequencing analysis provide fast and clinically relevant research data allowing the identification of novel critical players from both the invading fungus and the host. The data from the current study would not only help to decipher disease mechanisms but also promote the discovery of novel antifungal drug targets.

Clinical Aspects of Immune Damage in Cryptococcosis

Purpose of review

To perform an extensive review of recent literature and provide an update on the current epidemiology, clinical features and management of cryptococcal disease with a focus on the differences between patients depending on their immune status.

Recent findings

Emerging literature has highlighted the inflammatory pathophysiology and varied manifestations of cryptococcal infections in patients who are apparently healthy but paradoxically have a more critical clinical course compared to their immunosuppressed counterparts.

Summary

Non-HIV cryptococcal meningitis has greater mortality compared to that seen in HIV patients. Basic science experiments closely analyzing the underlying pathophysiological response to this infection have demonstrated the predominant role of T cell-mediated inflammatory injury in causing worse clinical outcomes. Further studies are needed to define the need for immunosuppressive agents in the treatment of this illness.

Diagnosis and Management of Central Nervous System Cryptococcal Infections in HIV-Infected Adults

Cryptococcal meningitis persists as a significant source of morbidity and mortality in persons with HIV/AIDS, particularly in sub-Saharan Africa. Despite increasing access to antiretrovirals, persons presenting with advanced HIV disease remains common, and Cryptococcus remains the most frequent etiology of adult meningitis. We performed a literature review and herein present the most up-to-date information on the diagnosis and management of cryptococcosis. Recent advances have dramatically improved the accessibility of timely and affordable diagnostics. The optimal initial antifungal management has been newly updated after the completion of a landmark clinical trial. Beyond antifungals, the control of intracranial pressure and mitigation of toxicities remain hallmarks of effective treatment. Cryptococcal meningitis continues to present challenging complications and continued research is needed.

Pulmonary Iron Limitation Induced by Exogenous Type I IFN Protects Mice from Cryptococcus gattii Independently of T Cells

Cryptococcus neoformans and Cryptococcus gattii cause fatal infection in immunodeficient and immunocompetent individuals. While these fungi are sibling species, C. gattii infects very few AIDS patients, while C. neoformans infection is an AIDS-defining illness, suggesting that the host response to HIV selects C. neoformans over C. gattii. We used a viral mimic molecule (pICLC) to stimulate the immune response, and pICLC treatment improved mouse outcomes from both species. pICLC-induced action against C. neoformans was due to activation of well-defined immune pathways known to deter C. neoformans, whereas these immune pathways were dispensable for pICLC treatment of C. gattii. Since these immune pathways are eventually destroyed by HIV/AIDS, our data help explain why the antiviral immune response in AIDS patients is unable to control C. neoformans infection but is protective against C. gattii. Furthermore, pICLC induced tighter control of iron in the lungs of mice, which inhibited C. gattii, thus suggesting an entirely new mode of nutritional immunity activated by viral signals.

Cryptococcus neoformans causes deadly mycosis primarily in AIDS patients, whereas Cryptococcus gattii infects mostly non-HIV patients, even in regions with high burdens of HIV/AIDS and an established environmental presence of C. gattii. As HIV induces type I IFN (t1IFN), we hypothesized that t1IFN would differentially affect the outcome of C. neoformans and C. gattii infections. Exogenous t1IFN induction using stabilized poly(I·C) (pICLC) improved murine outcomes in either cryptococcal infection. In C. neoformans-infected mice, pICLC activity was associated with C. neoformans containment and classical Th1 immunity. In contrast, pICLC activity against C. gattii did not require any immune factors previously associated with C. neoformans immunity: T, B, and NK cells, IFN-γ, and macrophages were all dispensable. Interestingly, C. gattii pICLC activity depended on β-2-microglobulin, which impacts iron levels among other functions. Iron supplementation reversed pICLC activity, suggesting C. gattii pICLC activity requires iron limitation. Also, pICLC induced a set of iron control proteins, some of which were directly inhibitory to cryptococcus in vitro, suggesting t1IFN regulates iron availability in the pulmonary air space fluids. Thus, exogenous induction of t1IFN significantly improves the outcome of murine infection by C. gattii and C. neoformans but by distinct mechanisms; the C. gattii effect was mediated by iron limitation, while the effect on C. neoformans infection was through induction of classical T-cell-dependent immunity. Together this difference in types of T-cell-dependent t1IFN immunity for different Cryptococcus species suggests a possible mechanism by which HIV infection may select against C. gattii but not C. neoformans.

Blood neutrophil counts in HIV-infected patients with cryptococcal meningitis: Association with mortality

BACKGROUND

The mortality from cryptococcal meningitis remains high, despite the availability of antiretroviral therapy (ART) and amphotericin-based fungal regimens. The role of neutrophils in cryptococcosis is controversial. Our objective was to examine the association between blood neutrophil counts and outcomes in terms of mortality, the incidence of bacterial infections (including Mycobacterium tuberculosis) and hospitalization among HIV-infected patients presenting with cryptococcal meningitis.

METHODS

We used data from participants from the Cryptococcal Optimal ART Timing (COAT) trial (2010-2012; Uganda and South Africa) and the Adjunctive Sertraline for Treatment of Cryptococcal Meningitis (ASTRO-CM) trial (2013-2017; Uganda). We estimated 30-day mortality risk with Cox proportional hazards models by baseline neutrophil counts (a) on a continuous scale and (b) with indicators for both relatively high (> 3,500 cells/mm3) and low (≤ 1,000 cells/mm3) counts. Follow-up neutrophil counts from the COAT trial were used to examine the time-dependent association of neutrophil counts with 12-month mortality and rehospitalization.

RESULTS

801 participants had an absolute neutrophil value at meningitis diagnosis. The median baseline absolute neutrophil count was 2100 cells/mm3 (IQR, 1400 to 3300 cells/mm3). Baseline neutrophil count was positively associated with 30-day mortality (adjusted hazard ratio = 1.09, 95%CI, 1.04-1.13, per 1000 cells/mm3 increase; p<0.001). Baseline absolute neutrophil counts ≤ 1000 cells/mm3 did not have increased risk of 30-day mortality compared to those with baseline neutrophils of 1001-3500 cells/mm3; however, baseline >3500 cells/mm3 had significantly increased risk, with an adjusted hazard ratio of 1.85(95%CI, 1.40-2.44; p<0.001). Among the COAT participants with follow-up neutrophil data, there was a strong association between time-updated neutrophil count and 12-month mortality (adjusted hazard ratio = 1.16, 95% CI 1.09-1.24; p<0.001.

CONCLUSION

Higher blood neutrophil counts in HIV-infected patients with cryptococcal meningitis were associated with mortality. Neutrophils role requires further investigation as to whether this may be a mediator directly contributing to mortality or merely a marker of underlying pathologies that increase mortality risk.

Antibody Responses in HIV-Infected Patients With Advanced Immunosuppression and Asymptomatic Cryptococcal Antigenemia

Background

There are no host biomarkers of risk for HIV-associated cryptococcal meningitis (CM) except CD4+ T-cell deficiency. At present, serum cryptococcal antigen (CrAg) screening of those with CD4 <100 cells/µL is used to identify persons at risk for HIV-associated CM. We determined if plasma antibody profiles could discriminate CrAg+ from CrAg- patients.

Methods

We performed serological analyses of 237 HIV-infected asymptomatic Zimbabwean patients with CD4 <100 cells/µL; 125 CrAg- and CrAg+ but cerebrospinal fluid CrAg- by CrAg lateral flow assay. We measured plasma immunoglobulin M (IgM), immunoglobulin G (IgG) 1, and IgG2 concentrations by Luminex, and titers of Cryptococcus neoformans (Cn) glucuronoxylomannan (GXM) polysaccharide and naturally occurring Laminarin (natural Lam, a β-(1–3)-glucan linked polysaccharide)-binding IgM and IgG by enzyme-linked immunosorbent assay.

Results

GXM-IgG, -IgM, and -IgG2 levels were significantly higher in CrAg+ patients, whereas natural Lam-IgM and Lam-IgG were higher in CrAg- patients before and after adjustment for age, sex, and CD4 T-cell count, despite overlap of values. To address this variability and better discriminate the groups, we used Akaike Information Criteria to select variables that independently predicted CrAg+ status and included them in a receiver operating characteristic curve to predict CrAg status. By inclusion of CD4, GXM-IgG, GXM-IgM, and Lam-IgG, -IgG2, and -IgM, this model had an 80.4% probability (95% confidence interval, 0.75–0.86) of predicting CrAg+ status.

Conclusions

Statistical models that include multiple serological variables may improve the identification of patients at risk for CM and inform new directions in research on the complex role that antibodies may play in resistance and susceptibility to CM.