Oral versus intravenous flucytosine in patients with human immunodeficiency virus-associated cryptococcal meningitis.

In a randomized controlled trial of amphotericin B-based therapy for human immunodeficiency virus (HIV)-associated cryptococcal meningitis in Thailand, we also compared the mycological efficacy, toxicity, and pharmacokinetics of oral versus intravenous flucytosine at 100 mg/kg of body weight/day for the initial 2 weeks. Half of 32 patients assigned to the two arms containing flucytosine were randomized to oral and half to intravenous flucytosine. Early fungicidal activity was determined from serial quantitative cultures of cerebrospinal fluid (CSF), and toxicity was assessed by clinical and laboratory monitoring. Flucytosine and fluorouracil concentrations in plasma and CSF were measured by high-performance liquid chromatography. No significant bone marrow or hepatotoxicity was seen, there was no detectable difference in bone marrow toxicity between patients on intravenous and those on oral formulation, and no patients discontinued treatment. In patients receiving intravenous flucytosine, the median 24-h area under the concentration-time curve was significantly higher than in the oral group. Despite this difference, there was no difference in early fungicidal activity between patients on intravenous compared with patients on oral flucytosine. The results suggest that either formulation can be used safely at this dosage in a developing country setting, without drug concentration monitoring. The bioavailability of the oral formulation may be reduced in late-stage HIV-infected patients in Thailand. Concentrations of flucytosine with intravenous formulation at 100 mg/kg/day may be in excess of those required for maximal fungicidal activity.

Immune dysfunction in HIV-seronegative, Cryptococcus gattii meningitis.

The pathophysiology of meningitis caused by Cryptococcus gattii in apparently immunocompetent individuals remains unclear. We measured multiple cytokines in CSF from a HIV-seronegative, apparently immunocompetent, Thai patient with C. gattii meningitis, over the first 2 weeks of antifungal therapy. Levels of proinflammatory IFN-gamma, TNF-alpha, and IL-6 were very low compared to patients with HIV-related Cryptococcus neoformans meningitis and of IL-10 very high. While patients with C. gattii meningitis may be a heterogeneous group, these data suggest in this case a maladapted immune response to cryptococcal exposure had allowed progression to clinical cryptococcal disease.

Intrathecal production and secretion of vascular endothelial growth factor during Cryptococcal Meningitis.

BACKGROUND: Patients with cryptococcal meningitis (CM) show elevated intracranial pressure (ICP) and blood-brain barrier (BBB) disruption in most cases. Elevated ICP is an important contributor to mortality. Vascular endothelial growth factor (VEGF) might be the mediator of BBB disruption during CM. METHODS: We measured VEGF levels in serum, plasma, and cerebrospinal fluid (CSF) of 95 patients and 63 control subjects, and we analyzed the required trigger and cellular source of VEGF secretion in vitro. RESULTS: Cryptococcus neoformans and its capsular antigens dose-dependently induced VEGF secretion by polymorphonuclear neutrophils, monocytes, and peripheral blood mononuclear cells (PBMCs). VEGF production by PBMCs induced by antigens strongly exceeded production by monocytes (P<.001). The addition of major histocompatibility complex class II antibody inhibited this production of VEGF (P=.005). Confirming the in vitro data, patients with CM showed significantly elevated VEGF levels in CSF (P<.001), plasma (P=.028), and serum (P<.001), compared with healthy control subjects. Calculated VEGF indices demonstrated that VEGF was produced intrathecally. CONCLUSIONS: Our findings suggest that VEGF plays a role in the pathophysiology of CM. We propose that CD4(+) T lymphocytes--stimulated by monocytes acting as antigen-presenting cells--are the cells that produce VEGF in response to cryptococcal antigens.

Combination antifungal therapies for HIV-associated cryptococcal meningitis: a randomised trial.

BACKGROUND: It frequently takes more than 2 weeks for drug treatments for cryptococcal meningitis to sterilise cerebrospinal fluid (CSF). In-vitro and animal studies lend support to the use of combinations of amphotericin B, flucytosine, and fluconazole for treatment of cryptococcosis. We compared the fungicidal activity of combinations of these drugs for initial treatment of patients with cryptococcal meningitis. METHODS: 64 patients with a first episode of HIV-associated cryptococcal meningitis were randomised to initial treatment with: amphotericin B (0.7 mg/kg daily); amphotericin B plus flucytosine (100 mg/kg daily); amphotericin B plus fluconazole (400 mg daily); or triple therapy with amphotericin B, flucytosine, and fluconazole. Our primary endpoint was fungicidal activity, measured by the rate of reduction in CSF cryptococcal colony-forming units (CFU) from serial quantitative CSF cultures on days 3, 7, and 14 of treatment. FINDINGS: Baseline CSF CFU counts were an important prognostic factor. Clearance of cryptococci from the CSF was exponential and was significantly faster with amphotericin B plus flucytosine than with amphotericin B alone (p=0.0006), amphotericin B plus fluconazole ( p=0.02), or triple therapy (p=0.02). INTERPRETATION: At these doses, amphotericin B plus flucytosine is the most rapidly fungicidal regimen. Quantification of CSF cultures provides a powerful new means to accurately assess the fungicidal activity of new treatment regimens for cryptococcal meningitis.

Development and evaluation of rapid urinary antigen detection tests for diagnosis of penicilliosis marneffei.

Penicilliosis, caused by the dimorphic fungus Penicillium marneffei, is an important opportunistic systemic fungal infection affecting immunocompromised individuals living in areas where penicilliosis is endemic. We have demonstrated previously that a urinary enzyme-linked immunosorbent assay (ELISA) with purified rabbit polyclonal antibody against killed whole-fission-form arthroconidia of P. marneffei was specific and highly sensitive for the diagnosis of penicilliosis. In this study, a dot blot ELISA and a latex agglutination (LA) test were developed with the same polyclonal antibody and compared with the ELISA for the detection of P. marneffei urinary antigen. Urine specimens from 37 patients with culture-proven penicilliosis and 300 controls (52 healthy subjects and 248 hospitalized patients without penicilliosis) were tested. Antigen was detected in urine from all 37 (100%) penicilliosis patients by the LA test, 35 (94.6%) penicilliosis patients by the dot blot ELISA, and 36 (97.3%) penicilliosis patients by the ELISA. False-positive results were found by the three assays for 2 (0.7%), 8 (2.7%), and 6 (2%) of 300 controls, respectively. The overall sensitivities of the diagnostic tests were as follows: dot blot ELISA, 94.6%; ELISA, 97.3%; and LA test, 100% (specificities, 97.3, 98, and 99.3%, respectively). The LA test is simple, robust, rapid, and convenient and should prove to be an important addition to the existing diagnostic tests for penicilliosis.

A randomized, double-blind, placebo-controlled trial of acetazolamide for the treatment of elevated intracranial pressure in cryptococcal meningitis.

We conducted a trial of oral acetazolamide for the treatment of cryptococcal meningitis in 22 Thai adults with headache and an opening cerebrospinal fluid pressure of >/=200 mm H(2)0. The trial was terminated prematurely because patients who received acetazolamide developed significantly lower venous bicarbonate levels and higher chloride levels and had more-frequent serious adverse events than did subjects who received placebo.