Histoplasmosis

Monoclonal antibodies to heat shock protein 60 alter the pathogenesis of Histoplasma capsulatum

Heat shock proteins with molecular masses of approximately 60 kDa (Hsp60) are widely distributed in nature and are highly conserved immunogenic molecules that can function as molecular chaperones and enhance cellular survival under physiological stress conditions. The fungus Histoplasma capsulatum displays an Hsp60 on its cell surface that is a key target of the cellular immune response during histoplasmosis, and immunization with this protein is protective. However, the role of humoral responses to Hsp60 has not been fully elucidated. We generated immunoglobulin G (IgG) isotype monoclonal antibodies (MAbs) to H. capsulatum Hsp60. IgG1 and IgG2a MAbs significantly prolonged the survival of mice infected with H. capsulatum. An IgG2b MAb was not protective. The protective MAbs reduced intracellular fungal survival and increased phagolysosomal fusion of macrophages in vitro. Histological examination of infected mice showed that protective MAbs reduced the fungal burden and organ damage. Organs of infected animals treated with protective MAbs had significantly increased levels of interleukin-2 (IL-2), IL-12, and tumor necrosis factor alpha and decreased levels of IL-4 and IL-10. Hence, IgG1 and IgG2a MAbs to Hsp60 can modify H. capsulatum pathogenesis in part by altering the intracellular fate of the fungus and inducing the production of Th1-associated cytokines.

Two specific strains of Histoplasma capsulatum causing mucocutaneous manifestations of histoplasmosis: preliminary analysis of a frequent manifestation of histoplasmosis in southern Brazil

OBJECTIVES

Skin lesions, uncommon in US cases (<10%), occur in 38-85% of cases reported from Latin America. Although these differences may reflect reporting bias, delayed diagnosis, or differences in host immune response among different ethnic groups, they also could result from genetic differences changing the pathobiology of the organism. It is possible that genetic differences among strains of H. capsulatum may influence the pathogenesis and clinical manifestations of histoplasmosis.

METHODS

We examined the clinical features of patients with mucocutaneous manifestations of histoplasmosis and performed genetic analysis based on nucleotide sequence variations in the internal transcribed spacer regions of rRNA genes of H. capsulatum isolates of patients. Two pairs of PCR primers were designed to develop and amplify the ITS regions of H. capsulatum, 5'-TACCCGGCCACCCTTGTCTA-3' and 5'-AGCGGGTGGCAAAGCCC-3'. These primers were based on the ITS sequence of Ajellomyces capsulatus, the ascomycetous teleomorph form of H. capsulatum, deposited in the GenBank (accession number U18363). Eight patients attending a tertiary-care hospital in southern Brazil were enrolled into the study. All case patients had skin cultures growing H. capsulatum at the mycology laboratory.

RESULTS

Six of eight (75%) patients were HIV-positive and presented involvement of multiples organs by H. capsulatum. Two HIV-negative patients did not present evidence of involvement of other organs besides mucosa and skin. ITS sequencing of a DNA H. capsulatum fragment of 485-bp from isolates of 8 patients revealed two distinct strains. The 2 distinct fragments (Hc1, Hc2) differed from each other at 7 positions in the ITS regions. They were identical to strains of H. capsulatum isolated in patients from Colombia and Argentina, but different from strains isolated in US. Hc1 and Hc2 were isolated in 5 patients and 3 patients, respectively, with mucocutaneous manifestations of histoplasmosis. Both Hc1 and Hc2 strains were isolated in HIV-infected and non-HIV-infected patients.

CONCLUSIONS

Mucocutaneous manifestations of histoplasmosis, which are frequently seen in Brazilian patients were caused by 2 specific strains in our institution. Those strains have been isolated in patients with these particular clinical features of histoplasmosis in Latin America. Our study suggests that unique pathogenic characteristics among the Latin American species of H. capsulatum might explain its increased dermatotropism.

Acute respiratory infections in a recently arrived traveler to your part of the world

Many acute infectious pulmonary diseases have incubation periods that are long enough for travelers to have symptoms after returning home to a health-care system that is not familiar with "foreign" infections. Respiratory infections have a relatively limited repertoire of clinical manifestations, so that there is often nothing characteristic enough about a specific infection to make the diagnosis obvious. Thus, the pathway to the diagnosis of infections that are not endemic in a region relies heavily on taking a thorough history of both itinerary and of specific exposures. One important caveat is that on occasion, the history of a recent trip creates an element of "tunnel vision" in the evaluating health-care provider. It is tempting to relate a person's problem to that recent trip; however, when evaluating recent returnees, it is always important to remember that the travel may have nothing to do with the patient's presentation. Recent travel may add diagnostic considerations to the list of possibilities, but an astute clinician must not disregard the possibility that the patient's illness has nothing to do with the recent trip.

Literature review and case histories of Histoplasma capsulatum var. duboisii infections in HIV-infected patients

African histoplasmosis during HIV infection is rare.

African histoplasmosis caused by Histoplasma capsulatum var. duboisii is an invasive fungal infection endemic in central and west Africa. Most of its ecology and pathogenesis remain unknown. H. capsulatum var. capsulatum is an AIDS-defining opportunistic infection in HIV-infected patients who are living in or have traveled to histoplasmosis-endemic areas. In contrast, reports concerning African histoplasmosis during HIV infection are rare, although both pathogens coexist in those regions. We report 3 cases of imported African histoplasmosis diagnosed in France in HIV-infected patients and a literature review on similar cases.

Temperature-induced switch to the pathogenic yeast form of Histoplasma capsulatum requires Ryp1, a conserved transcriptional regulator

Histoplasma capsulatum, a fungal pathogen of humans, switches from a filamentous spore-forming mold in the soil to a pathogenic budding-yeast form in the human host. This morphologic switch, which is exhibited by H. capsulatum and a group of evolutionarily related fungal pathogens, is regulated by temperature. Using insertional mutagenesis, we identified a gene, RYP1 (required for yeast phase growth), which is required for yeast-form growth at 37 degrees C. ryp1 mutants are constitutively filamentous irrespective of temperature. Ryp1 is a member of a family of fungal proteins that includes Wor1, a master transcriptional regulator of the white-opaque transition required for mating in Candida albicans. Ryp1 associates with its own upstream regulatory region, consistent with a direct role in transcriptional control, and both the protein and its transcript accumulate to high levels in wild-type yeast-phase cells. Microarray analysis demonstrated that Ryp1 is required for the expression of the vast majority of yeast-specific genes, including two genes linked to virulence. Thus, Ryp1 appears to be a critical transcriptional regulator of a temperature-regulated morphologic switch in H. capsulatum.

Comparison of fungal culture versus surgical pathology examination in the detection of Histoplasma in surgically excised pulmonary granulomas

CONTEXT

Granulomatous pulmonary nodules are common in areas endemic for Histoplasma infection, and may require surgical excision to exclude neoplasia. Surgeons may elect to routinely send material directly to the clinical microbiology laboratory for fungal and mycobacterial cultures.

OBJECTIVE

To determine if tissue from surgically excised pulmonary granulomatous nodules removed from patients in a geographic area endemic for Histoplasma infection should be routinely submitted for fungal culture.

DESIGN

Retrospective review and comparison of surgical pathology histochemical findings and clinical microbiology results of 30 surgical (wedge) lung excisions that demonstrated granulomatous nodule at the time of frozen section.

RESULTS

Twenty cases demonstrated fungal organisms consistent with Histoplasma species via histochemical fungal stains. Of these 20 cases, 17 were tested in the microbiology laboratory using direct smear examination and fungal culture; Histoplasma was detected in 1 case (1/17). Eight cases revealed no organisms by surgical pathology. Of these, 6 were tested in the microbiology laboratory, and all 6 were negative by culture and direct smear (0/6). The remaining 2 cases demonstrated organisms other than Histoplasma by surgical pathology examination.

CONCLUSIONS

Surgical pathology examination of granulomatous pulmonary nodules detected Histoplasma organisms with greater sensitivity than culture and direct smear. There were no false-negative surgical pathology diagnoses when compared with microbiological results. These findings suggest that it is not necessary to routinely send material from solitary pulmonary granulomas for fungal culture when the material is removed from immunocompetent patients in a geographic area endemic for histoplasmosis.

Invasive fungal infections and antifungal therapies in solid organ transplant recipients

This manuscript will review the risk factors, prevalence, clinical presentation, and management of invasive fungal infections (IFIs) in solid organ transplant (SOT) recipients. Primary literature was obtained via MEDLINE (1966-April 2007) and EMBASE. Abstracts were obtained from scientific meetings or pharmaceutical manufacturers and included in the analysis. All studies and abstracts evaluating IFIs and/or antifungal therapies, with a primary focus on solid organ transplantation, were considered for inclusion. English-language literature was selected for inclusion, but was limited to those consisting of human subjects. Infectious complications following SOT are common. IFIs are associated with high morbidity and mortality rates in this patient population. Determining the best course of therapy is difficult due to the limited availability of data in SOT recipients. Well-designed clinical studies are infrequent and much of the available information is often based on case-reports or retrospective analyses. Transplant practitioners must remain aware of their therapeutic options and the advantages and disadvantages associated with the available treatment alternatives.

Disseminated histoplasmosis and tuberculosis in a patient with HIV infection

Histoplasmosis is a very rare disease in Korea. Clinical manifestations are very similar to those of tuberculosis. This is the first case report of combined disseminated histoplasmosis and tuberculosis in a patient with HIV infection in Korea. A 42-year-old Korean with Acquired Immunodeficiency Syndrome (AIDS) was diagnosed with tuberculosis. He had lived in Guatemala for the past five years. Upon diagnosis of disseminated tuberculosis with HIV infection, he was treated with anti-tuberculosis medications and anti-retroviral agents. Fever, weakness, hepatosplenomegaly and pancytopenia were persistent despite treatment. The patient's history of living in Guatemala caused us to seek opportunistic infectious organisms other than tuberculosis. Bone marrow aspiration and biopsy were performed and the result revealed numerous intracellular organisms consistent with Histoplasma capsulatum; therefore, the diagnosis of disseminated histoplasmosis was made.

Unusual manifestation of histoplasmosis in connective tissue diseases

This report describes the coexistence of three patients with rheumatic diseases (systemic lupus erythematosus, rheumatoid arthritis, and dermatomyositis) and infections because of Histoplasma capsulatum. Connective tissue diseases and histoplasmosis share several clinical findings. Therefore, histoplasmosis could be misdiagnosed as connective tissue disease or a flare of these diseases. Such cases highlight the importance of awareness of histoplasmosis in immunocompromised patients, particularly in those originating from endemic areas.

Mucocutaneous manifestations of disseminated histoplasmosis in patients with acquired immunodeficiency syndrome: particular aspects in a Latin-American population

BACKGROUND

Mucocutaneous lesions in human immunodeficiency virus (HIV)-infected patients with disseminated histoplasmosis have a wide spectrum of clinical manifestations, making its diagnosis difficult. Studies have been restricted to case reports and series with small numbers of patients not specifically focusing on the dermatological aspects of histoplasmosis.

AIMS

To describe the characteristics of mucocutaneous lesions of disseminated histoplasmosis in HIV-infected patients.

METHODS

A retrospective and prospective study was conducted on 36 HIV-infected patients with mucocutaneous histoplasmosis in a tertiary-care hospital in Brazil.

RESULTS

Mucocutaneous histoplasmosis was diagnosed by histopathology in 33 of the 36 patients (91%) and/or culture in 23 (64%). Their CD4+ cell counts ranged from 2 to 103 cells/mm(3). The average number of different morphological types of lesions was three per patient. Despite the variability of the lesions, papules (50%), crusted papules (64%) and oral mucosal erosions and/or ulcers (58%) were the most frequent dermatological lesions. A diffuse pattern of distribution of the skin lesions was found in 58% of the cases. There was significant association between the CD4+ cell counts and the morphological variability of lesions per patient. Variation in the lesions seemed to be associated with higher CD4+ cell counts.

CONCLUSION

Doctors caring for HIV-infected patients should be aware of the wide spectrum of dermatological lesions observed in disseminated histoplasmosis and the importance of detecting and isolating the fungus in mucocutaneous tissues.

Systemic histoplasmosis: a 15-year retrospective institutional review of 111 patients

To our knowledge, an institutional review of systemic histoplasmosis has not been conducted in the United States since the major outbreaks in Indianapolis in 1978-4982. We conducted a retrospective review of all patients with systemic histoplasmosis diagnosed at Mayo Clinic over a 15-year period. The case definitions employed were based on an international consensus statement by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group (EORTC/IFICG) and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (MSG). One hundred eleven patients with systemic histoplasmosis were identified between January 1, 1991, and December 31, 2005. Of these, 78 patients had disseminated histoplasmosis and 55 patients had Histoplasma capsulatum fungemia. The mean age of patients was 55 years, 66% were male, and 98% were white. Fifty-nine percent of patients were immunocompromised. Fever was the most frequently reported symptom (63%), followed by respiratory complaints (43%) and weight loss (37%). The peripheral white blood cell count was <3000 cells/mm in 28%, hemoglobin was <10 g/dL in 29%, and platelet count was <150,000 cells/mm in 41% of patients. Liver enzymes were elevated (alanine aminotransferase >60 U/L in 39%, aspartate aminotransferase >60 U/L in 27%), alkaline phosphatase was >200 U/L in 55%, and albumin was <3.5 g/dL in 70%. Serologic and histopathologic examinations were each positive in 75% of cases, Histoplasma urine antigen screening was positive in 80%, and H. capsulatum was culture positive in 84%. Forty-seven percent of patients were sequentially treated with an amphotericin B-containing product followed by itraconazole, 31% received itraconazole alone, and 7% received an amphotericin B-containing product only. Another 13% of patients did not receive antifungal treatment, and the remaining 2% did not have treatment data available. Sixty percent of patients required hospitalization, and in hospital mortality was 6% with a median survival time of 61 days. The relapse rate was 9%, with a median relapse-free survival of 857 days. Systemic histoplasmosis should be suspected in patients who have lived in endemic areas with fever, bone marrow suppression, and elevated hepatic enzymes, particularly if they are immunocompromised. Evaluation including a combination of Histoplasma serologic screening, urine antigen assay, and fungal culture will secure the diagnosis in most cases.

HIV infection with concomitant cerebral toxoplasmosis and disseminated histoplasmosis in a 45-year-old man

Although disseminated histoplasmosis is a common opportunistic infection in HIV patients in endemic areas, it is not widely known in Japan. We report a rare case of a man from Ghana infected with HIV who was hospitalized in Japan and who suffered from coinfection with cerebral toxoplasmosis and disseminated histoplasmosis. The diagnosis of cerebral toxoplasmosis was confirmed by a brain biopsy, and the therapy for the disease resulted in almost complete resolution of the brain lesion. However, fever of unknown origin continued for 2 weeks, and disseminated histoplasmosis was diagnosed by examination of a blood smear and by the detection of the histoplasma genome in the peripheral blood by means of polymerase chain reaction. The isolate was confirmed to be Histoplasma capsulatum var. duboisii. Therapy with amphotericin B was initiated, and no histoplasma genome in the peripheral blood was detected 3 days later. Unfortunately, the patient died after 10 days from acute respiratory syndrome. This case highlights that histoplasmosis should be included in the differential diagnosis of opportunistic infections in AIDS patients when patients have a history of travel to or arrival from endemic areas.

Histoplasmoma: Isolated central nervous system infection with Histoplasma capsulatum in a patient with AIDS

Histoplasma capsulatum is endemic to the Ohio and Mississippi River valleys. Exposure to H. capsulatum is very common in this region and usually follows a benign clinical course. However, immunocompromised hosts, like those with HIV/AIDS, are more susceptible to symptomatic infection, and have a greater chance of developing disseminated disease. We report an unusual case of a patient with AIDS presenting with a single ring-enhancing brain lesion and a focal neurological deficit. Workup was unrevealing, and brain biopsy was felt to represent too much risk as the lesion was located at the right tegmentum. The lesion enlarged over a period of months, and he underwent radiation therapy after the lesion caused obstructive hydrocephalus. He expired soon after completion of radiation therapy. At autopsy, the mass lesion was noted to contain organisms constant with H. capsulatum, pathologically consistent with a histoplasmoma.

Histoplasmosis: a clinical and laboratory update

Infection with Histoplasma capsulatum occurs commonly in areas in the Midwestern United States and Central America, but symptomatic disease requiring medical care is manifest in very few patients. The extent of disease depends on the number of conidia inhaled and the function of the host's cellular immune system. Pulmonary infection is the primary manifestation of histoplasmosis, varying from mild pneumonitis to severe acute respiratory distress syndrome. In those with emphysema, a chronic progressive form of histoplasmosis can ensue. Dissemination of H. capsulatum within macrophages is common and becomes symptomatic primarily in patients with defects in cellular immunity. The spectrum of disseminated infection includes acute, severe, life-threatening sepsis and chronic, slowly progressive infection. Diagnostic accuracy has improved greatly with the use of an assay for Histoplasma antigen in the urine; serology remains useful for certain forms of histoplasmosis, and culture is the ultimate confirming diagnostic test. Classically, histoplasmosis has been treated with long courses of amphotericin B. Today, amphotericin B is rarely used except for severe infection and then only for a few weeks, followed by azole therapy. Itraconazole is the azole of choice following initial amphotericin B treatment and for primary treatment of mild to moderate histoplasmosis.

A quick and cost-effective method for diagnosing disseminated histoplasmosis in children

The examination of fecal mucus for detecting yeast cells of Histoplasma capsulatum has proved to be a useful tool for diagnosing disseminated histoplasmosis in paediatric patients in a study of 13 cases carried out in Ecuador.

Ileal perforation and reactive hemophagocytic syndrome in a patient with disseminated histoplasmosis: the role of the real-time polymerase chain reaction in the diagnosis and successful treatment with amphotericin B lipid complex

The following case illustrates an ileal perforation and reactive hemophagocytic syndrome (RHS) resulting from disseminated histoplasmosis in a patient with Human Immunodeficiency Virus (HIV) from Puerto Rico. Although the diagnosis was established by histopathologic findings and a positive bone marrow culture, Histoplasma capsulatum-specific real-time Polymerase Chain Reaction (PCR) allowed to confirm the diagnosis from formalin-fixed, paraffin-embedded tissue. Interestingly, the Histoplasma antigens in both serum and urine samples were falsely negative. Amphotericin B lipid complex (Abelcet), followed by oral itraconazole, led to a successful response and resolution of symptoms. A short review of the clinical signs and symptoms, diagnostic tests, and therapeutic options for disseminated histoplasmosis is done, with emphasis on the role of Histoplasma-specific real-time PCR as a molecular diagnostic tool and the efficacy of treatment with one of the lipid formulations of amphotericin B.

Disseminated histoplasmosis presenting as thrombotic microangiopathy

BACKGROUND

Thrombotic microangiopathies (TMA) are systemic vasoocclusive disorders associated with significant morbidity and mortality. Rapid and reliable diagnosis of TMA is critical. The diagnosis is complicated by a lack of objective and sensitive laboratory testing as well as multiple concurrent diseases, including infectious processes.

CASE STUDY

We report two cases of disseminated histoplasmosis associated with TMA manifestations in renal transplant recipients, including one patient with histologically documented renal microthrombi; both patients were referred for plasma exchange. After the diagnosis of histoplasmosis, the treatment plan was changed to antifungal medications, reduced immuno-suppression, and supportive care, with progressive resolution of TMA manifestations.

CONCLUSION

TMA occurs in transplant populations in association with infections, medications, and other factors. Appropriate management includes recognition and treatment of possible etiological factors. Disseminated histoplasmosis should be considered in transplant patients presenting with TMA.

A case of disseminated histoplasmosis successfully treated with the investigational drug posaconazole

A 79-year-old man with a 3-month history of weight loss and fever was diagnosed with disseminated histoplasmosis. When the infection became refractory to itraconazole therapy, posaconazole was prescribed. The patient became asymptomatic within 1 month of beginning treatment, and his general health improved. Posaconazole was discontinued after 6 months, and the patient has remained well since.

Chronic disseminated histoplasmosis with lesions restricted to the mouth: case report

We report a rare case of chronic disseminated histoplasmosis with several ulcerated lesions in the oral cavity in an alcoholic patient without human immunodeficiency virus infection, with no detectable signs and symptoms of systemic disease or extraoral manifestations. Histopathological analysis revealed chronic inflammatory process with granulomas containing Histoplasma-like organisms. The isolation of Histoplasma capsulatum provided the definitive diagnosis. Treatment with itraconazole resulted in complete remission of oral lesions. As far we aware, this is the second case report of oral histoplasmosis in an HIV negative patient described in Brazil.

DIAGNOSIS OF HISTOPLASMOSIS

Endemic mycoses can be challenging to diagnose and accurate interpretation of laboratory data is important to ensure the most appropriate treatment for the patients. Although the definitive diagnosis of histoplasmosis (HP), one of the most frequent endemic mycoses in the world, is achieved by direct diagnosis performed by micro and/or macroscopic observation of Histoplasma capsulatum (H. capsulatum), serologic evidence of this fungal infection is important since the isolation of the etiologic agents is time-consuming and insensitive. A variety of immunoassays have been used to detect specific antibodies to H. capsulatum. The most applied technique for antibody detection is immunodiffusion with sensitivity between 70 to 100 % and specificity of 100%, depending on the clinical form. The complement fixation (CF) test, a methodology extensively used on the past, is less specific (60 to 90%). Detecting fungal antigens by immunoassays is valuable in immunocompromised individuals where such assays achieve positive predictive values of 96-98%. Most current tests in diagnostic laboratories still utilize unpurified antigenic complexes from either whole fungal cells or their culture filtrates. Emphasis has shifted, however, to clinical immunoassays using highly purified and well-characterized antigens including recombinant antigens. In this paper, we review the current conventional diagnostic tools, such as complement fixation and immunodiffusion, outline the development of novel diagnostic reagents and methods, and discuss their relative merits and disadvantages to the immunodiagnostic of this mycosis.

Histoplasmosis in dogs and cats

Histoplasma capsulatum is endemic throughout most of the United States with a high prevalence of infections in the Midwest and South. Histoplasmosis is the second most common systemic fungal disease in cats that may be more susceptible than dogs. Infection occurs by inhalation of conidia from the mycelial phase, which subsequently convert to the yeast form. Histoplasma capsulatum is phagocytized and harbored by cells of the mononuclear phagocyte system. Infection may be subclinical or cause clinical pulmonary granulomatous disease or dissemination. Disseminated disease predominantly affects the liver, spleen, gastrointestinal tract, bone and bone marrow, integument, and eyes. Primary gastrointestinal histoplasmosis also occurs. Clinical signs of histoplasmosis often are nonspecific, including chronic wasting, fever, anorexia, respiratory signs, and lameness. Gastrointestinal signs (eg, diarrhea with hematochezia or melena) are common in dogs. The definitive diagnosis is made by identification of the yeast in tissue samples. Itraconazole is the treatment of choice.

[Pseudotumoral presentation of American pulmonary histioplasmosis]

In France, American pulmonary histoplasmosis is an imported deep mycosis, caused by inhalation of Histoplasma capsulatum. Clinical and radiological features of this exotic disease are multiple, simulating tuberculosis or cancer. We report two cases of American histoplasmosis with pseudo-tumoral form, in immunocompetent subjects working in Venezuela, with a multinodular pulmonary presentation.

Genetic diversity ofHistoplasma capsulatumstrains in Brazil

This study establishes the genetic relatedness among Brazilian Histoplasma capsulatum samples obtained from different sources. A PCR-based random amplified polymorphic DNA (RAPD) assay was used to delineate polymorphisms among isolates in geographically diverse regions in Brazil. RAPD fingerprints revealed distinct DNA profiles and provided a high level of discrimination among H. capsulatum strains from different locations. Cluster I was composed of H. capsulatum isolates from the northeast region. The majority of strains from southeast and south were categorized as major cluster II. The strain 84564 from Rio de Janeiro State showed no genetic correlation to any of the isolates from the same state. The RAPD patterns of H. capsulatum isolates from Goias (Cluster III) were unrelated to DNA fingerprints observed among the other H. capsulatum strains (48% similarity). This study is the first report that stratifies the clusters of H. capsulatum strains from Brazil by molecular typing and associates them with the geographical origin.

Histoplasmosis: presentaciones clínicas y pruebas de laboratorio en un centro brasileño

Histoplasmosis, caused by the dimorphic fungus Histoplasma capsulatum, is endemic in many regions of the Americas, Asia and Africa. It has a wide spectrum of clinical manifestations, from asymptomatic infection to severe disseminated disease. A retrospective study was carried out to describe the clinical forms and assess the clinical significance of the laboratory diagnostic tests of patients with histoplasmosis during the period of July 1987 to December 2003 at Instituto de Pesquisa Clínica Evandro Chagas/ FIOCRUZ, RJ, Brazil. Seventy-four patients were included. Forty-nine percent of the cases (n = 36) occurred in HIV positive patients who presented with disseminated disease. The remaining 38 cases were classified in different clinical forms. Histoplasma capsulatum was isolated from 69.5% of the clinical specimens sent to culture. Immunodiffusion and immunoblot were positive in 72.6% and 100% of the performed tests, respectively. Histopathologic findings suggestive of H. capsulatum were found in 63.2% of the performed exams. Serology had a lower proportion of positivity amongst AIDS patients, when compared with HIV negative patients (X2 = 6.65; p lower than 0.008). Statistical differences between AIDS and non-AIDS patients were not observed with culture and histopathology. The specific role of each test varies according to the clinical form. Physicians need to know the value and limitations of the available diagnostic tests, but before that, they have to think about histoplasmosis and consider this clinical entity in their differential diagnosis.

Disseminated histoplasmosis in persons with interferon-gamma receptor 1 deficiency

Mutations in the interferon (IFN)-gamma receptor predispose to infection with bacille Calmette-Guérin, nontuberculous mycobacteria, and Salmonella organisms. We identified a patient with recurrent disseminated Histoplasma capsulatum osteomyelitis who had an autosomal dominant form of IFN-gamma receptor 1 deficiency (i.e., a 4-bp deletion at or near base 818). IFN-gamma-mediated immunity is important in the control of histoplasmosis.

Disseminated histoplasmosis in patients with AIDS in Panama: a review of 104 cases

We identified the incidence and primary clinical characteristics of histoplasmosis in patients with acquired immunodeficiency syndrome (AIDS) in our hospital. Disseminated histoplasmosis is a common and severe disease among patients with AIDS in Panama and should be suspected for patients with a CD4 cell count of <100 cells/ microL, fever, respiratory symptoms, weight loss, and diarrhea.

Serious infections associated with anticytokine therapies in the rheumatic diseases

The ability to target and neutralize macrophage-derived inflammatory cytokines, particularly tumor necrosis factor-alpha (TNF-alpha), has emerged in recent years as one of the most important advances in the treatment of rheumatoid arthritis, Crohn's disease, and several other systemic inflammatory diseases. In rheumatoid arthritis, for example, these biological agents rapidly reduce signs and symptoms of joint inflammation and profoundly slow the progression of joint damage. However, data that have emerged following Food and Drug Administration approval of these agents have alerted clinicians to an increased likelihood of opportunistic infections in patients treated with these agents, particularly tuberculosis. The effect of TNF inhibition on the frequency of infection with more common bacterial pathogens is less clear. Animal models of tuberculosis and other opportunistic infections have demonstrated the importance of TNF-alpha in controlling and containing intracellular pathogens. The spectrum of infections reported to date in the setting of anti-TNF-alpha treatment is reviewed here. In addition, relevant animal data illustrating potential mechanistic roles for TNF-alpha in host responses to infection are also reviewed.

High 18F-fluorodeoxyglocose uptake in adrenal histoplasmosis; a case report

Adrenal histoplasmosis is one of the most common adrenal granulomatous infections in endemic areas. Although CT or MRI findings of adrenal histoplasmosis have been documented, there are no reports regarding 18F-fluorodeoxyglocose (FDG) positron emission tomography (PET) findings. We report a case of bilateral adrenal histoplasmosis showing a significantly high uptake of 18F-fluorodeoxyglocose on PET study. Adrenal histoplasmosis should be considered as one of the differential diagnoses in cases of adrenal tumors with intense FDG uptake, even in non-endemic areas.

Histoplasmose pulmonar aguda no Rio Grande do Sul

INTRODUÇÃO: A histoplasmose pulmonar aguda depende da inalação de uma grande quantidade de propágulos fúngicos por um paciente hígido. O tempo de exposição determina a gravidade da doença. Uma epidemia é influenciada por fatores que afetam o crescimento e a transmissão do Histoplasma capsulatum var. capsulatum na natureza. OBJETIVO: Identificar os aspectos epidemiológicos e clínico-laboratoriais dos pacientes com histoplasmose pulmonar aguda no Rio Grande do Sul e compará-los com as microepidemias relatadas no Brasil. MÉTODO: Foram revisados 212 prontuários clínicos de pacientes com histoplasmose dos arquivos do Laboratório de Micologia do Complexo Hospitalar Santa Casa de Porto Alegre (RS) num período de 25 anos (1977-2002). Foram identificados e incluídos no estudo os casos de histoplasmose pulmonar aguda com cultivo positivo e/ou achado histopatológico compatível. As microepidemias foram diagnosticadas com a comprovação de um caso ou evidência soromicológica com história clínica compatível. Foram revisadas as microepidemias publicadas no Brasil. RESULTADOS: Dezoito de um total de 212 pacientes (8,5%) foram incluídos no trabalho. A idade variou de 8 a 63 anos (média de 35,4; mediana de 34,5), e 67% eram do sexo masculino. A história epidemiológica foi sugestiva em 11 pacientes (61%). O tipo primário de histoplasmose pulmonar aguda foi o mais freqüente (17; 95%). Houve predomínio de casos isolados. CONCLUSÃO: O reconhecimento de casos isolados e a presença de microepidemias demonstram a abundância do H. capsulatum no solo, e juntamente com a ocorrência de todas as formas da doença, confirmam o Rio Grande do Sul como hiperendêmico para histoplasmose.

Emerging fungal diseases: the importance of the host

More yeasts and molds are now recognized to cause more human disease than ever before. This development is not due to a change in the virulence of these fungi, but rather to changes in the human host. These changes include immunosuppression secondary to the pandemic of HIV, the use of life-saving advances in chemotherapy and organ transplantation, and the use of corticosteroids and other immunosuppressive agents to treat a variety of diseases. Fungi that were once considered common saprophytes are now recognized as potential pathogens in these patients. This situation necessitates better communication than ever between the clinician, pathologist, and clinical mycologist to ensure the prompt and accurate determination of the cause of fungal diseases.

Disseminated histoplasmosis in a nonendemic area

Health care providers in the areas where histoplasmosis is not endemic can benefit greatly from understanding the clinical presentation, diagnosis and management of disseminated histoplasmosis as patients from the endemic areas may travel to and require medical attention in areas of low disease prevalence. Use of effective diagnostic tools such as Histoplasma antigen detection can aid in providing timely and appropriate therapy.

ELISA for early diagnosis of histoplasmosis

An ELISA was developed and evaluated as a method for detecting antibodies against glycosylated and deglycosylated histoplasmin (HMIN). Sera from patients with histoplasmosis, paracoccidioidomycosis, sporotrichosis, coccidioidomycosis, aspergillosis, cryptococcosis and healthy donors were tested by ELISA against purified, deglycosylated histoplasmin (ptHMIN) and compared with purified, native (i.e. glycosylated) histoplasmin (pHMIN). Although cross-reactivity was not abolished when ptHMIN was used in the test, it was reduced (pHMIN ELISA 93 % versus ptHMIN ELISA 96 %). However, there were statistically significant differences between the sensitivities of these two methods for the detection of antibodies (pHMIN ELISA 57 % versus ptHMIN ELISA 92 %; P < 0.001) and between the efficiency of the methods (pHMIN ELISA 83 % versus ptHMIN ELISA 95 %; P < 0.001). These parameters compare better than previously published data relating to the use of treated HMIN in diagnostic ELISAs. Some of the reactivities of serum samples were compared by immunoblotting using deglycosylated HMIN and by immunodiffusion using the crude antigen. The results demonstrated that cross-reactions with heterologous sera in both ELISAs could also be observed in immunoblotting and arose from shared protein epitopes. These data suggest that ELISA using deglycosylated HMIN is a very sensitive diagnostic method and, by using commercially available antigen, it can be easily standardized and performed faster than previous Western blot-based tests using the same antigen. It provides a useful adjunct to existing methods of diagnosis that could be applied even in situations where laboratory facilities were relatively limited.

Chronic disseminated histoplasmosis in an apparently immuno-competent Belgian patient

A 77 year-old Belgian man was admitted for weight loss and elevated liver enzymes. He used to live in Central Africa until 1986 and denied any travel outside Belgium during the last decade. Physical examination was unremarkable except for a lip ulceration. Blood tests showed increases of liver enzymes and CEA. In the search of an abdominal cancer, CT showed a normal liver but enlarged surrenal glands, while colonoscopy disclosed multiple mucosal lesions. Colic and lip biopsies identified Histoplasma capsulatum var capsulatum. HIV serology was negative. Lymphocyte count was normal but lymphocyte function was depressed. The patient dramatically improved under oral treatment with Itraconazole 400 mg daily for six months. This case indicates that chronic disseminated Histoplasmosis can reactivate in a healthy and apparently non-immunocompromised person living in Europe.