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ABSTRACT: Indoleamine 2,3 dioxygenase (IDO) plays an important role in immunoregulation as it is involved in downregulating immune responses to infections. We sought to characterize IDO activity in histoplasmosis and to do so, C57Bl6 mice were infected intranasally with Histoplasma capsulatum. After infection, lung and spleen IDO activity was assessed by HPLC and IDO expression by qRT-PCR. The distribution of IDO was determined by immunohistochemical staining. Cytokine levels were measured in lung and spleen homogenates using cytokine bead array. Fungal burden was quantified by culture. Subcutaneous pellets containing methyltryptophane (1-MT) were employed to inhibit IDO in vivo. Histoplasma infection strongly induced functional lung IDO, with activity at its highest at weeks 1 and 2 and then decreased thereafter as the mice cleared the infection. Lung IDO activity positively correlated with the fungal burden (Rho = 0.845), interferon-γ (Rho = 0.839) and tumor necrosis factor-α (Rho = 0.791) levels, P < 0.001. In contrast, spleen IDO activity was not induced despite high infection burden and cytokine levels. IDO expressing cells were predominately located at the ring edge of Histoplasma-induced granulomas. IDO inhibition prior to infection reduced fungal burdens and inflammation in lungs and spleen. Histoplasma preferentially induces lung IDO, as early as one week after infection. IDO appears to modulate the immune response to Histoplasma infection.
Medical mycology: official publication of the International Society for Human and Animal Mycology 11/2012; · 2.13 Impact Factor
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ABSTRACT: This report describes clinical manifestations of histoplasmosis in 6-month-old dizygotic twins, one of whom developed disseminated histoplasmosis of infancy while his sibling remained well, but developed serologic evidence of histoplasmosis. The report also documents histoplasma antigen concentrations in serum and urine before, during and after completing antifungal therapy.
The Pediatric Infectious Disease Journal 05/2012; 31(9):990-1. · 3.58 Impact Factor
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ABSTRACT: We demonstrated that sodium gluconate was the factor causing false-positive galactomannan (GM) antigenemia of Plasma-Lyte hydration solution. Infusion of sodium gluconate-containing solution but not gluconate-free Plasma-Lyte resulted in positive serum GM antigenemia. Serum GM concentrations also correlated with the volume and in vitro concentrations of GM within gluconate-containing solutions of infused Plasma-Lyte.
Journal of clinical microbiology 12/2011; 49(12):4330-2. · 4.16 Impact Factor
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ABSTRACT: The second-generation MVista Blastomyces antigen enzyme immunoassay was not quantitative; therefore, specimens obtained previously were tested in the same assay as new specimens to assess the change in antigen levels. Furthermore, the sensitivity in serum had not been fully evaluated. The purpose of this study was to evaluate a quantitative Blastomyces antigen assay and detection of antigen in serum. Calibrators containing known concentrations of Blastomyces galactomannan were used to quantify antigen in urine and serum from patients with proven blastomycosis and from controls. Paired current and previously obtained urine specimens were tested to determine if quantification eliminated the need for concurrent testing to assess change in antigen. Pretreatment of serum with EDTA at 104°C was evaluated to determine if dissociation of immune complexes improved detection of antigenemia. Antigenuria was detected in 89.9% of patients with culture- or histopathology-proven blastomycosis. Specificity was 99.0% in patients with nonfungal infections and healthy subjects, but cross-reactions occurred in 95.6% of patients with histoplasmosis. Change in antigen level categorized as increase, no change, or decrease based on antigen units determined in the same assay agreed closely with the category of change in ng/ml determined from different assays. Pretreatment increased the sensitivity of detection of antigenemia from 35.7% to 57.1%. Quantification eliminated the need for concurrent testing of current and previously obtained specimens for assessment of changes in antigen concentration. Pretreatment increased the sensitivity for detection of antigenemia. Differentiation of histoplasmosis and blastomycosis is not possible by antigen detection.
Clinical and vaccine immunology: CVI 11/2011; 19(1):53-6. · 2.37 Impact Factor
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ABSTRACT: It is well known that cross reactions with other fungal pathogens including Histoplasma capsulatum can occur with the use of the Platelia™ Aspergillus galactomannan assay. We report two patients with confirmed blastomycosis whose bronchoalveolar lavage (BAL) fluid tested positive for Aspergillus galactomannan despite no evidence of aspergillosis.
Medical mycology: official publication of the International Society for Human and Animal Mycology 09/2011; 50(4):396-8. · 2.13 Impact Factor
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Chadi A Hage,
Julie A Ribes,
Nancy L Wengenack,
Larry M Baddour,
Maha Assi,
David S McKinsey,
Kassem Hammoud,
Daisy Alapat,
N Esther Babady,
Michelle Parker,
DeAnna Fuller,
Aliya Noor,
Thomas E Davis,
Mark Rodgers,
Patricia A Connolly,
Boutros El Haddad, L Joseph Wheat
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ABSTRACT: The sensitivity of the MVista Histoplasma antigen enzyme immunoassay (MiraVista Diagnostics) has been evaluated in disseminated histoplasmosis in patients with AIDS and in the "epidemic" form of acute pneumonia. Moreover, there has been no evaluation of the sensitivity of antigenemia detection in disseminated histoplasmosis after the implementation of methods to dissociate immune complexes and denature released antibodies. The goal of this study was to determine the sensitivity of the current antigen assay in different categories of histoplasmosis.
Urine and serum specimens obtained from 218 patients with histoplasmosis and 229 control subjects, including 30 with blastomycosis, were tested.
Antigenuria was detected in 91.8% of 158 patients with disseminated histoplasmosis, 83.3% of 6 patients with acute histoplasmosis, 30.4% of 46 patients with subacute histoplasmosis, and 87.5% of 8 patients with chronic pulmonary histoplasmosis; antigenemia was present in 100% of 31 tested cases of disseminated histoplasmosis. Among patients with disseminated cases, antigenuria was detected more often and at higher concentrations in immunocompromised patients and those with severe disease. Specificity was 99.0% for patients with nonfungal infections (n = 130) and in healthy subjects (n = 69), but cross-reactivity occurred in 90% of patients with blastomycosis.
The sensitivity of antigen detection in disseminated histoplasmosis is higher in immunocompromised patients than in immunocompetent patients and in patients with more severe illness. The sensitivity for detection of antigenemia is similar to that for antigenuria in disseminated infection.
Clinical Infectious Diseases 09/2011; 53(5):448-54. · 9.15 Impact Factor
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ABSTRACT: Several endemic mycoses cause cross-reactions in the Histoplasma antigen enzyme immunoassay. Herein, a positive Histoplasma antigen result has been recognized in a patient with sporotrichosis.
Clinical and vaccine immunology: CVI 08/2011; 18(10):1781-2. · 2.37 Impact Factor
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ABSTRACT: Micafungin alone and combined with liposomal amphotericin B was evaluated against two strains of Histoplasma capsulatum. Micafungin was active in vitro against the mold but not the yeast form but was ineffective in vivo. Micafungin appears to be ineffective in treatment of histoplasmosis.
Antimicrobial Agents and Chemotherapy 06/2011; 55(9):4447-50. · 4.84 Impact Factor
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ABSTRACT: Blastomycosis is a serious and potentially fatal infection, and diagnosis can be difficult at times. We evaluated the diagnostic utility of a commercially available assay for detection of Blastomyces dermatitidis antigen, recently modified to permit quantitation, in subjects with newly diagnosed blastomycosis. Twenty-three of 27 (85.1%) subjects had detectable B. dermatitidis antigenuria. In 2 of these 23, positive results were obtained after concentration of the urine specimen. Nine of 11 (81.8%) subjects had detectable B. dermatitidis antigen in serum, including 3 subjects with negative results before treatment of serum with ethylenediaminetetraacetic acid (EDTA) and positive results after EDTA treatment. B. dermatitidis antigen was not detected in specimens from 50 control subjects but was detected in 15 patients with histoplasmosis. B. dermatitidis antigen was detected in most of the patients with blastomycosis and can be a useful tool for timely diagnosis.
Diagnostic microbiology and infectious disease 02/2011; 69(2):187-91. · 2.45 Impact Factor
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ABSTRACT: Clearance of Histoplasma antigen has been used as a marker for response to treatment of progressive disseminated histoplasmosis (PDH) in patients with AIDS. Advancements in Histoplasma antigen detection permit accurate quantification of antigen concentration. We compared the clearance of antigenemia and antigenuria during effective treatment of PDH. Urine and serum specimens were serially collected from patients with AIDS who were successfully treated for PDH as part of two prospective clinical trials. Samples were stored frozen until they were tested in the quantitative Histoplasma antigen enzyme immunoassay. The kinetics of antigen clearance during the first 12 weeks of therapy were assessed in urine and serum during treatment with liposomal or deoxycholate amphotericin B followed by itraconazole and, in a separate analysis, in patients receiving only itraconazole. Latent class growth analysis was performed to define patterns of antigen clearance over time. In patients receiving amphotericin B, antigen levels declined the most during the first 2 weeks of treatment and antigenemia decreased more rapidly than antigenuria (5.90 ng/ml per week versus 4.21 ng/ml per week, respectively; P = 0.09). Mean reductions of antigen levels from baseline at weeks 2 and 12 were greater in sera than in urine: 11.26 ng/ml versus 7.65 ng/ml (P = 0.0948) and 18.52 ng/ml versus 14.64 ng/ml (P = 0.0440), respectively. In patients who received itraconazole alone, most of the decline in antigenuria occurred later during treatment and was overall slower than that seen with amphotericin B (P < 0.0001). Results of latent class growth modeling showed two distinct trajectories for each parameter. With effective therapy, Histoplasma antigenemia decreases more rapidly than antigenuria, providing a more sensitive early laboratory marker for response to treatment. Antigenuria declines earlier with amphotericin B than with itraconazole.
Clinical and vaccine immunology: CVI 02/2011; 18(4):661-6. · 2.37 Impact Factor
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ABSTRACT: The endemic region of blastomycosis historically has included the state of Indiana. However, few published reports of blastomycosis exist to substantiate this distinction. A surge of patients with blastomycosis in central Indiana (Indianapolis and surrounding counties) beginning in 2005 prompted us to review our local experience. We propose that this surge was related to major highway construction around Indianapolis.
We reviewed all microbiologically confirmed cases from four hospitals serving central Indiana. Chart review was completed for adult patients, and data were collected on clinical presentations, methods of diagnosis, comorbidities, radiologic findings, treatment, and outcomes. We plotted patient residence addresses with sites of highway construction.
Fifty-nine patients were identified from laboratory results and physician referral. Interestingly, a surge of blastomycosis incidence occurred in 34 patients between 2005 and 2008 during which time major highway projects were under way around the Indianapolis metropolitan area. The majority of these patients presented acutely and with pulmonary involvement. Fungal culture and antigen testing were the most sensitive means to diagnosis. Antifungal therapy was highly effective.
This urban outbreak of blastomycosis in Indianapolis should prompt clinicians to consider blastomycosis in this highly endemic area of histoplasmosis.
Chest 12/2010; 138(6):1377-82. · 5.25 Impact Factor
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ABSTRACT: Invasive pulmonary aspergillosis (IPA) is a major cause of mortality in patients with stem cell transplants and hematologic malignancies. Timely diagnosis of IPA improves survival but is difficult to make. We evaluated the effectiveness of bronchoalveolar lavage (BAL) galactomannan (GM) in diagnosing IPA in these populations by retrospectively reviewing records of 67 consecutive patients, in whom 89 BAL GM tests were performed. For patients with IPA, only the first BAL sample linked to the IPA episode was analyzed. Eighty samples were associated with proven, 12 with probable, and 32 with possible invasive fungal infections (IFI), and 37 were associated with no IFI. Among patients with IFIs, 4 had proven, 11 probable, and 32 possible IPA. Using BAL GM ≥ 0.5 (cutoff for serum GM) and ≥ 0.85 (optimal cutoff identified by receiver-operating characteristic curve), the sensitivity in diagnosing proven or probable IPA was 73% (11/15) and 67% (10/15), respectively, and specificity was 89% (33/37) and 95% (35/37). At these cutoffs, positive and negative predictive values were 73% (11/15) and 83% (10/12), and 89% (33/37) and 87% (35/40), respectively. BAL GM was more sensitive than cytology (0%, 0/14), BAL culture (27%, 4/15), transbronchial biopsy (40%, 2/5), or serum GM (67%, 10/15) for diagnosing IPA. BAL GM was ≥ 0.85 and ≥ 0.5 in 86% (6/7) and 100% (7/7) of patients with proven or probable IPA who received a mold-active agent for ≤ 3 days. BAL GM added sensitivity to serum GM and other means of diagnosing IPA, and was not impacted by short courses of mold-active agents.
Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 11/2010; 17(7):1043-50. · 3.15 Impact Factor
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ABSTRACT: During a Histoplasma outbreak in a colony of fruit bats at a southern United States zoo, it was observed that although Histoplasma was recovered in culture from multiple sites at necropsy, none of the samples collected from those bats tested positive for Histoplasma antigen (HAg). Five of the Histoplasma isolates from the bats were subsequently identified as Latin American (LA) clade A, restriction fragment length polymorphism (RFLP) class 6. These observations raised concern as to whether the commercially available HAg test could detect Histoplasma antigen not of the North American clade upon which the HAg test had been developed. To evaluate this concern, a murine model of disseminated histoplasmosis was established, and mice were infected with multiple LA Histoplasma isolates, including clinical isolates recovered from Brazilian AIDS patients (RFLP class 5 and class 6) and isolates recovered from the bats during the outbreak (RFLP class 6). Histoplasma antigen was detected in all infected mice in our experiments, even when Histoplasma was not recovered in culture. Because the currently available HAg test is able to detect Histoplasma antigen in mice infected with Latin American isolates, this suggests that bat host factors rather than differences among Histoplasma RFLP classes were responsible for the inability to detect HAg in infected bats.
Clinical and vaccine immunology: CVI 03/2010; 17(5):802-6. · 2.37 Impact Factor
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Clinical Infectious Diseases 01/2010; 50(1):122-3; author reply 123-4. · 9.15 Impact Factor
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ABSTRACT: Life-threatening histoplasmosis is one of the most common opportunistic infections in patients receiving tumor necrosis factor (TNF) blockers. Delays in considering the diagnosis may lead to increased morbidity and mortality. Most affected patients present with pneumonitis, usually accompanied by additional signs of progressive dissemination, or with signs of progressive dissemination alone. The diagnosis often can be promptly established using antigen detection or direct examination of bronchoalveolar lavage specimens. If histoplasmosis is diagnosed promptly, antifungal therapy is highly effective. After a favorable clinical response, the safety of both discontinuation of antifungal therapy and the resumption of TNF blocker remains undetermined. The management of the immune reconstitution inflammatory syndrome that may follow discontinuation of TNF blockers also requires investigation. Prescribers should become aware of the recognition, diagnosis, and treatment of histoplasmosis and educate recipients about decreasing their risk of exposure and both recognizing and reporting signs of early infection.
Clinical Infectious Diseases 12/2009; 50(1):85-92. · 9.15 Impact Factor
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ABSTRACT: Detection of antigen in BAL is useful for diagnosis of histoplasmosis. The MVista Histoplasma antigen enzyme immunoassay has been modified to permit quantification. The purpose of this study is to compare the sensitivity of the quantitative antigen detection assay with cytopathology and culture of BAL specimens.
BAL from patients with histoplasmosis who were evaluated at the Indiana University Medical Center and controls without histoplasmosis were studied. BAL fluid was tested in the quantitative Histoplasma antigen assay.
Antigen was detected in the BAL in 93.5% of patients with histoplasmosis, 80% with blastomycosis, and 0% of controls with nonfungal infections. Antigen was detected in the urine of 79% and serum in 65% of patients with histoplasmosis. Cytopathology was positive in 48% and culture in 48% of patients with histoplasmosis, and 40% and 60% of patients with blastomycosis, respectively. Serology was positive in 65%. Combining BAL antigen detection and BAL cytopathology, both methods for rapid diagnosis, the sensitivity was 96.8% in histoplasmosis and 80% in blastomycosis.
Detection of antigen in BAL complements antigen detection in serum and urine as an objective diagnostic test for histoplasmosis.
Chest 10/2009; 137(3):623-8. · 5.25 Impact Factor
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ABSTRACT: Having reported that pretreatment of serum samples with EDTA at 100 degrees C improved the sensitivity for the detection of Histoplasma antigenemia, we have evaluated this method for the detection of Coccidioides antigenemia. Urine and serum samples from patients with coccidioidomycosis were tested using the MVista Coccidioides enzyme immunoassay, and serum samples with and without EDTA-heat treatment were tested. Antigenemia was detected in 28.6% of patients whose samples were not EDTA-heat treated and in 73.1% of those whose samples were treated. Antigenuria was detected in 50% of patients. Specificity of 100% was obtained in healthy subjects, but cross-reactions were seen in 22.2% of patients with histoplasmosis or blastomycosis. EDTA-heat treatment improves the sensitivity for the detection of Coccidioides antigenemia.
Clinical and vaccine immunology: CVI 09/2009; 16(10):1453-6. · 2.37 Impact Factor
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L Joseph Wheat
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ABSTRACT: The endemic mycoses are often overlooked in the evaluation of community-acquired pneumonia, and appropriate testing is not performed until the patient has failed to improve on antibacterial therapy. Antigen detection and fungal serology may be helpful in diagnosis of endemic mycoses as causes for pneumonia. Guidelines for recognition and evaluation of endemic mycoses as causes for community-acquired pneumonia are proposed. Performance of antigen testing on bronchial washings or lavage fluid may improve the sensitivity for diagnosis over microscopic examination and the speed of diagnosis over culture. This article focuses on antigen detection and serology for diagnosis of endemic mycoses. Of note is that isolation of the fungus by culture remains the only method for definitive diagnosis, and the only method for diagnosis in some patients.
Clinics in chest medicine 07/2009; 30(2):379-89, viii. · 2.51 Impact Factor
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L Joseph Wheat
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ABSTRACT: Detection of galactomannan antigen in serum or bronchoalveolar lavage fluid is useful for diagnosis of invasive aspergillosis, but the current serologic tests are not useful. (1-->3)-beta-D-glucan can be detected in the serum of patients who have aspergillosis, candidiasis, and a few other mold infections, but false-positive results limit its reliability for diagnosis. None of these methods is useful for diagnosis of zygomycosis and certain other less common mold infections. This article focuses on the detection of antigen and beta-D-glucan for diagnosis of invasive aspergillosis and candidiasis.
Clinics in chest medicine 06/2009; 30(2):367-77, viii. · 2.51 Impact Factor
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ABSTRACT: In a retrospective review of 24 patients with histoplasmosis, blastomycosis, or coccidioidomycosis treated with voriconazole (most for salvage therapy), the outcome was favorable (improved or stable) for 22 (95.8%) within 2 months of starting voriconazole and for 20 (83.3%) at the last follow-up. Prospective studies are required to determine its role in the treatment of endemic mycoses.
Antimicrobial Agents and Chemotherapy 02/2009; 53(4):1648-51. · 4.84 Impact Factor
