David Boulware

SUMMARYAIDS-related cryptococcal meningitis continues to cause a substantial burden of death in low and middle income countries. The diagnostic use for detection of cryptococcal capsular polysaccharide antigen (CrAg) in serum and cerebrospinal fluid by latex agglutination test (CrAg-latex) or enzyme-linked immunoassay (EIA) has been available for over decades. Better diagnostics in asymptomatic and symptomatic phases of cryptococcosis are key components to reduce mortality. Recently, the cryptococcal antigen lateral flow assay (CrAg LFA) was included in the armamentarium for diagnosis. Unlike the other tests, the CrAg LFA is a dipstick immunochromatographic assay, in a format similar to the home pregnancy test, and requires little or no lab infrastructure. This test meets all of the World Health Organization ASSURED criteria (Affordable, Sensitive, Specific, User friendly, Rapid/robust, Equipment-free, and Delivered). CrAg LFA in serum, plasma, whole blood, or cerebrospinal fluid is...

Histoplasmosis is endemic to the Midwestern United States, but cases have been reported nearly worldwide. A 1970 study found 3.8% skin test sensitivity to Histoplasma capsulatum in Uganda but no systemic study of histoplasmosis exposure has occurred since the onset of the human immunodeficiency virus (HIV) pandemic. This study investigated the seroprevalence of H. capsulatum and sought previously undetected cases of histoplasmosis in Kampala, Uganda. Serum, cerebrospinal fluid (CSF) and/or urine specimens were obtained from HIV-infected persons with suspected meningitis. Specimens were tested for H. capsulatum IgG and IgM by enzyme immune assay and Histoplasma antigen. 147 of the 257 subjects who were enrolled had cryptococcal meningitis. Overall, 1.3% (2/151) of subjects were serum Histoplasma IgG positive, and zero of 151 were IgM positive. Antigen was not detected in any serum (n = 57), urine (n = 37, or CSF (n = 63) samples. Both subjects with serum Histoplasma IgG positivity had cryptococcal meningitis. Histoplasma capsulatum IgG was detected at low levels in persons with HIV/AIDS in Kampala, Uganda. Histoplasmosis is not widespread in Uganda but microfoci do exist. There appears to be no cross-reactivity between Cryptococcus neoformans and Histoplasma antigen testing, and cryptococcosis appears to be at most, a rare cause of positive Histoplasma IgG.

Background: Immune reconstitution inflammatory syndrome (IRIS) is a paradoxical inflammatory response that may occur after initiation of HIV antiretroviral therapy (ART). The pathophysiology of IRIS is unknown, and prospectively predicting those at risk of IRIS is not possible. Microarray technology is able to assess gene expression and immune activation after the initiation of ART. Methods: 17 IRIS events were identified prospectively in a cohort of 48 ART-naïve patients in Kampala, Uganda evaluated for 6 months after initiating ART. Prior to starting ART, 24 patients had no known opportunistic infections and 24 had cryptococcal meningitis (CM). Total RNA from whole blood was collected at 0, 2, 4, 8, & 12 weeks of ART, and gene expression was assessed using Affymetrix microarrays. Results: Among patients who did not develop IRIS, microarray analysis demonstrated that numerous gene expression markers of immune activation decreased in patients with ART. In particular, 41 transcripts ...

Background.  Cryptococcal meningitis is a leading cause of death in people living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome. The World Health Organizations recommends pre-antiretroviral treatment (ART) cryptococcal antigen (CRAG) screening in persons with CD4 below 100 cells/µL. We assessed the prevalence and outcome of cryptococcal antigenemia in rural southern Tanzania. Methods.  We conducted a retrospective study including all ART-naive adults with CD4 <150 cells/µL prospectively enrolled in the Kilombero and Ulanga Antiretroviral Cohort between 2008 and 2012. Cryptococcal antigen was assessed in cryopreserved pre-ART plasma. Cox regression estimated the composite outcome of death or loss to follow-up (LFU) by CRAG status and fluconazole use. Results.  Of 750 ART-naive adults, 28 (3.7%) were CRAG-positive, corresponding to a prevalence of 4.4% (23 of 520) in CD4 <100 and 2.2% (5 of 230) in CD4 100-150 cells/µL. Within 1 year, 75% (21 of 28) of CRAG-positive and 42% (302 of 722) of CRAG-negative patients were dead or LFU (P<.001), with no differences across CD4 strata. Cryptococcal antigen positivity was an independent predictor of death or LFU after adjusting for relevant confounders (hazard ratio [HR], 2.50; 95% confidence interval [CI], 1.29-4.83; P = .006). Cryptococcal meningitis occurred in 39% (11 of 28) of CRAG-positive patients, with similar retention-in-care regardless of meningitis diagnosis (P = .8). Cryptococcal antigen titer >1:160 was associated with meningitis development (odds ratio, 4.83; 95% CI, 1.24-8.41; P = .008). Fluconazole receipt decreased death or LFU in CRAG-positive patients (HR, 0.18; 95% CI, .04-.78; P = .022). Conclusions.  Cryptococcal antigenemia predicted mortality or LFU among ART-naive HIV-infected persons with CD4 <150 cells/µL, and fluconazole increased survival or retention-in-care, suggesting that targeted pre-ART CRAG screening may decrease early mortality or LFU. A CRAG screening threshold of CD4 <100 cells/µL missed 18% of CRAG-positive patients, suggesting guidelines should consider a higher threshold.

We report a case of a symptomatic relapse of HIV-related Cryptococcal meningoencephalitis eight years after the first diagnosis on the background of immune reconstitution. The findings as well as the clinical course suggests a combination of smouldering localised infection and enhanced inflammatory reaction related to immune restoration due to antiretroviral therapy. A combination of antifungal and anti-inflammatory therapy resulted in clinical and radiological improvement. Our case challenges the concept that immune reconstitution inflammatory syndrome and microbiological relapse are dichotomous entities.

This review provides an overview of Cryptococcus neoformans immunology and focuses on the pathogenesis of Cryptococcus-related paradoxical immune reconstitution inflammatory syndrome (IRIS). Cryptococcal IRIS has three phases: (1) before antiretroviral therapy (ART), with a paucity of cerebrospinal fluid (CSF) inflammation and defects in antigen clearance; (2) during initial ART immune recovery, with pro-inflammatory signaling by antigen-presenting cells without an effector response; and (3) at IRIS, a cytokine storm with a predominant type-1 helper T-cell (Th(1)) interferon-gamma (IFN-γ) response. Understanding IRIS pathogenesis allows for risk stratification and customization of HIV/AIDS care. In brief, persons at high IRIS risk may benefit from enhancing microbiologic clearance by use of adjunctive agents in combination with amphotericin, prolonging initial induction therapy, and/or increasing the initial consolidation antifungal therapy dose to at least 800 mg of fluconazole dai...

Latin America is the region with the third most AIDS-related cryptococcal meningitis infections globally. Highly active antiretroviral therapy (HAART) has reduced the number of infections; however, the number of deaths and the case-fatality rate continues to be unacceptable. In this review, we focus on the burden of AIDS-related cryptococcosis in Latin America and discuss potential strategies to reduce early mortality from Cryptococcus. In this review, we highlight the importance of: (1) earlier HIV diagnosis and HAART initiation with retention-in-care to avoid AIDS; (2) pre-HAART cryptococcal antigen (CRAG) screening with preemptive fluconazole treatment; (3) better diagnostics (e.g. CRAG testing); and (4) optimal treatment with aggressive management of intracranial pressure and induction therapy with antifungal combination. Implementation of these strategies can reduce cryptococcal-related deaths, improve care, and reduce healthcare costs.