Translational Development and Application of (1→3)-ß-d-Glucan for Diagnosis and Therapeutic Monitoring of Invasive Mycoses.

Early diagnosis and prompt initiation of appropriate antimicrobial therapy are crucial steps in the management of patients with invasive fungal infections. However, the diagnosis of invasive mycoses remains a major challenge in clinical practice, because presenting symptoms may be subtle and non-invasive diagnostic assays often lack sensitivity and specificity. Diagnosis is often expressed on a scale of probability (proven, probable and possible) based on a constellation of imaging findings, microbiological tools and histopathology, as there is no stand-alone assay for diagnosis. Recent data suggest that the carbohydrate biomarker (1→3)-ß-d-glucan may be useful in both the diagnosis and therapeutic monitoring of invasive fungal infections due to some yeasts, molds, and dimorphic fungi. In this paper, we review recent advances in the use of (1→3)-ß-d-glucan to monitor clinical response to antifungal therapy and explore how this assay may be used in the future.

Assessment of a real-time PCR method to detect human non-cryptococcal fungal meningitis.

BACKGROUND: The signs and symptoms associated with fungal meningitis are similar to those seen with more common bacterial infections. In this study, we investigate whether Aspergillus or Candida DNA can be detected in cerebrospinal fluid (CSF) samples from patients suspected of fungal meningitis using real-time PCR assay. METHODS: From April 2007 to November 2009, we evaluated CSF samples and sera from patients with risk factors for cerebral fungal meningitis in Nemazi Hospital, Shiraz University of Medical Sciences, Iran, by real-time PCR assay and routine mycological studies (direct microscopy examination and culture). Two CSF and two serum samples from each patient were examined.  RESULTS: CSF and serum samples from 38 patients (total: 152) suspected of fungal meningitis were examined. India ink staining and KOH smear were negative for all patients. C. albicans was isolated from two CSF samples. There were ten patients with positive real-time PCR results in their CSF samples: three patients had C. albicans, one with C. glabrata, four with Aspergillus species and two with both C. albicans and Aspergillus species DNA. Four patients had positive serum results for Aspergillus or Candida infections. CONCLUSION: Considering the findings, it seems that molecular examination can help in the diagnosis of fungal meningitis in patients with clinical and radiological presentations. Further studies should be conducted in other regions and settings to confirm these findings.

Cerebrospinal fluid and plasma (1-->3)-beta-D-glucan as surrogate markers for detection and monitoring of therapeutic response in experimental hematogenous Candida meningoencephalitis.

The treatment, diagnosis and therapeutic monitoring of hematogenous Candida meningoencephalitis (HCME) are not well understood. We therefore studied the expression of (1-->3)-beta-D-glucan (beta-glucan) in cerebrospinal fluid (CSF) and plasma in a nonneutropenic rabbit model of experimental HCME treated with micafungin and amphotericin B. Groups studied consisted of micafungin (0.5 to 32 mg/kg) and amphotericin B (1 mg/kg) treatment groups and the untreated controls (UC). Despite well-established infection in the cerebrum, cerebellum, choroid, vitreous humor (10(2) to 10(3) CFU/ml), spinal cord, and meninges (10 to 10(2) CFU/g), only 8.1% of UC CSF cultures were positive. By comparison, all 25 UC CSF samples tested for beta-glucan were positive (755 to 7,750 pg/ml) (P < 0.001). The therapeutic response in CNS tissue was site dependent, with significant decreases of the fungal burden in the cerebrum and cerebellum starting at 8 mg/kg, in the meninges at 2 mg/kg, and in the vitreous humor at 4 mg/kg. A dosage of 24 mg/kg was required to achieve a significant effect in the spinal cord and choroid. Clearance of Candida albicans from blood cultures was not predictive of eradication of organisms from the CNS; conversely, beta-glucan levels in CSF were predictive of the therapeutic response. A significant decrease of beta-glucan concentrations in CSF, in comparison to that for UC, started at 0.5 mg/kg (P < 0.001). Levels of plasma beta-glucan were lower than levels in simultaneously obtained CSF (P < 0.05). CSF beta-glucan levels correlated in a dose-dependent pattern with therapeutic responses and with Candida infection in cerebral tissue (r = 0.842). Micafungin demonstrated dose-dependent and site-dependent activity against HCME. CSF beta-glucan may be a useful biomarker for detection and monitoring of therapeutic response in HCME.

High human immunodeficiency virus type 1 RNA load in the cerebrospinal fluid from patients with lymphocytic meningitis.

Thirty-seven matched cerebrospinal fluid (CSF) and plasma samples from 34 human immunodeficiency virus type 1 (HIV-1)-infected patients with suspected meningitis were analyzed for levels of HIV-1 RNA and markers of inflammation. Patients with tuberculous (n = 9) or cryptococcal (n = 6) meningitis had the highest CSF virus loads, which in many cases exceeded the levels in plasma, compared with patients with meningococcal meningitis (n = 3), aseptic meningitis (n = 8), tuberculoma (n = 2), or AIDS dementia complex (n = 4) or with normal lumbar punctures (n = 3). CSF virus load correlated significantly with the number of infiltrating lymphocytes (r = .60, P < .001) but not with plasma virus load, the levels of beta2-microglobulin in the CSF, or the integrity of the blood-brain barrier. These data suggest significant intrathecal HIV-1 replication in patients with lymphocytic meningeal infections such as tuberculous and cryptococcal meningitis.

Coccidioidal antigen reactive CD4+ T-lymphocytes in the cerebrospinal fluid in coccidioides immitis meningitis.

CSF lymphocytes from patients with Coccidioides immitis meningitis exhibited a significant antigen-specific response to in vitro stimulation with C. immitis antigens. In some patients, lesser responses to control antigens (Candida and PPD) were also detected. Antigen-specific responses by CSF lymphocytes were seen early in the course of this disease as well as several years after patients had entered remission. When compared to CSF cells, the response of autologous peripheral blood mononuclear cells was similar but of a much smaller magnitude and at times undetectable. Fluorescence activated cell sorting revealed an increased percentage of CD3+ (T-cells), CD4+ (helper/inducer) and CD3+/HLA-DR+ (activated T-cell) cells in the CSF of C. immitis meningitis patients compared to their blood. Most of the antigen-specific proliferative response resided in the CD4+ lymphocyte subset. CSF T-cell proliferation assays may have a role in the diagnosis of C. immitis meningitis.

Utility of anti-WI-1 serological testing in the diagnosis of blastomycosis in Wisconsin residents.

WI-1, a 120-kD protein found in the outer cell wall of Blastomyces dermatitidis, has been purified, labeled with 125I, and used as a target in a radioimmunoassay (RIA). In an assessment of the usefulness of anti-WI-1 serology in the diagnosis of blastomycosis, the RIA was used to test four panels of sera from residents of Wisconsin, a state in which blastomycosis is endemic. Twenty-four (75%) of 32 patients whose blastomycosis had been reported to the Wisconsin Division of Health had at least one serum sample positive for antibody to WI-1; 25 (93%) of 27 serum samples obtained from these patients within 60 days of diagnosis were positive. In an effort to simulate clinical practice, 132 serum samples were assayed from another 107 patients in whom blastomycosis was being considered as a cause of illness. The result was positive for at least one sample from 83% of the 23 patients with confirmed blastomycosis and from 5% of the 84 patients from whom the fungus was not documented. Serum samples from another five patients with blastomycosis identified during investigation of a 1990 outbreak in Oconto Falls, Wisconsin, also gave a positive result, whereas none of the serum specimens from 57 healthy family members or neighbors did so. Only three (0.56%) of 535 serum samples from random blood donors residing in two counties with a high annual incidence of blastomycosis were positive for antibody to WI-1. Modification of the RIA so that IgM rather than IgG antibody was detected did not enhance diagnostic sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)