Search

Cutaneous infection by histoplasmosis in Cuban HIV patients was researched. In a case series study, all HIV patients admitted to "Pedro Kouri" Institute from January 1st, 1992 to June 30th, 2003, who had been diagnosed with cutaneous histoplasmosis, were included. Of 44 patients with histoplasmosis, 52% (23 cases) developed the progressive disseminated form of histoplasmosis, which behaved as a subacute weakening disease. Young adults represented 56.5% and 82.6% were males mainly Caucasian (91.3%). Most of cases came from the Western provinces. Histoplasmosis was a marker disease in 39.1% of cases. CD4+ T-lymphocyte counting under 200 cell/mm3 was present in 78.9% of patients. Histoplasmosis seems to behave as an important marker disease for AIDs in seropositive patients. Serology was not the diagnosing method of choice for this cutaneous disease in AIDS patients.

We observed false-positive results in the Platelia Aspergillus enzyme-linked immunoassay (EIA) for specimens from patients with histoplasmosis and mice with experimental infection. Platelia Aspergillus EIA-positive specimens were negative in the second-generation Histoplasma antigen EIA. Care must be taken to exclude histoplasmosis for patients with positive Platelia Aspergillus EIA results.

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.

False-positive Histoplasma antigenemia was reported in solid organ allograft recipients who had received rabbit anti-thymocyte globulin (RATG, RATG) caused by human anti-rabbit antibodies (HARA). A second-generation Histoplasma antigen detection assay was developed to overcome false positivity caused by HARA. With the second-generation assay, false-positive results were eliminated in 18 of 19 cases without reduction in the sensitivity in patients with histoplasmosis. In fact, sensitivity for detection of antigenuria in patients with acquired immunodeficiency syndrome and disseminated histoplasmosis was higher in the second-generation assay. Physicians should be aware of the potential for false-positive results in sandwich immunoassays in specimens from patients who have received RATG.

A new real-time PCR-based assay was used for detecting DNA of Histoplasma capsulatum in serum samples collected from four HIV-infected patients with proven histoplasmosis. The assay targeted the ITS1 region of rDNA and its in vitro sensitivity, specificity and reproducibility were evaluated. The technique detected DNA of H. capsulatum in all of the HIV-infected patients with proven histoplasmosis (4/4, 100%). The PCR result was positive for seven of the ten (70%) samples studied. The assay's specificity was determined to be 100%, since the method was negative for 25 other serum samples (10 from patients with proven aspergillosis and 15 from healthy controls). The PCR assay is a new and promising diagnostic alternative and further investigation is warranted.

We performed a retrospective study of 164 human immunodeficiency virus (HIV)-infected patients with disseminated histoplasmosis to identify the risk factors for death. Death occurred in 32% of the cases. Univariate analysis identified the following risk factors: diarrhea (odds ratio [OR] = 3.9, P = 0.001), neurologic manifestations (OR = 5.8, ; P = 0.001), hemoglobin level < 8.0g/dL (OR = 2.7, P = 0.004), urea level 2 times the normal upper limit (OR = 5.0, P < 0.001), creatinine level > 1.5 mg/dL (OR = 2.9, P = 0.005), aspartate aminotransferase (AST) level > 2.5 times the normal upper limit (OR = 3.1, P = 0.01), respiratory insufficiency (OR = 9.7, P < 0.001), sepsis (OR = 20.2, P < 0.001), and acute renal failure (OR = 2.5, P = 0.011). A hemoglobin level < 8.0 g/dL (OR = 3.8, P = 0.008), an AST level >or= 2.5 times the normal limit (OR = 1.0, P = 0.007), acute renal failure (OR = 2.96, P = 0.015), and respiratory insufficiency (OR = 12.2, P = 0.01) were independent risk factors for death.

The purpose of this work was to compare the efficacy of blood culture conventional method vs. a modified lysis/centrifugation technique. Out of 450 blood specimens received in one year, 100 where chosen for this comparative study: 60 from patients with AIDS, 15 from leukemic patients, ten from febrile neutropenic patients, five from patients with respiratory infections, five from diabetics and five from septicemic patients. The specimens were processed, simultaneously, according to the above mentioned methodologies with daily inspections searching for fungal growth in order to obtain the final identification of the causative agent. The number (40) of isolates recovered was the same using both methods, which included; 18 Candida albicans (45%), ten Candida spp. (25%), ten Histoplasma capsulatum (25%), and two Cryptococcus neoformans (5%). When the fungal growth time was compared by both methods, growth was more rapid when using the modified lysis/centrifugation technique than when using the conventional method. Statistical analysis revealed a significant difference (p<0.05) between them. The modified lysis/centrifugation technique showed to be more efficacious than the conventional one, and therefore the implementation of this methodology is highly recommended for the isolation of fungi from blood.

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.

During spring 2001, college students from Pennsylvania reported an acute febrile respiratory illness after returning from spring break vacation in Acapulco, Mexico. Acute pulmonary histoplasmosis was presumptively diagnosed and the cluster of illness was reported to the Centers of Disease Control and Prevention. A large investigation then ensued, which included finding student-travelers for interviews and requesting sera for histoplasmosis testing. We defined a clinical case by fever and at least one of the following: cough, shortness of breath, chest pain, or headache, in an Acapulco traveler during March-May 2001. A laboratory-confirmed case had positive serology. An initial study determined that the likely site of histoplasmosis exposure was Hotel H; we therefore performed a large cohort study among travelers who stayed at Hotel H. Of 757 contacted, 262 (36%) met the clinical case definition. Of 273 serum specimens tested, 148 (54%) were positive. Frequent use of Hotel H's stairwells, where construction was ongoing, was associated with increased risk of illness (relative risk = 10.5, 95% confidence interval = 3.7-30.5; P < 0.001). This is the first histoplasmosis outbreak associated with a hotel undergoing construction. Hotels in endemic areas should consider construction precaution measures to prevent histoplasmosis among their guests.

The purpose of this study was to determine whether serum lactate dehydrogenase (LDH) level could be used as an adjunct clinical marker to differentiate between histoplasmosis and Pneumocystis carinii pneumonia (PCP). In a retrospective, case-controlled study, 30 patients with a diagnosis of histoplasmosis (all but 1 with disseminated disease) were compared with 120 patients with PCP (33 patients with definitive PCP, 87 with presumed PCP). Groups were matched for CD4+ lymphocyte counts, sex, and year of diagnosis. The mean LDH level for patients with histoplasmosis was 1068 +/- 197 IU/L; for PCP, it was 375 +/- 23. An LDH level of more than 450 IU/L was 9.33 times more likely to be associated with a diagnosis of histoplasmosis than with PCP (odds ratio [OR], 9.33; 95% confidence interval [CI], 3.50-25.47; P < .01), and an LDH level of more than 600 IU/L was 9.41 times more likely to be so (OR, 9.41; 95% CI, 3.43-26.31; P < .01). An LDH level of 450 IU/L or greater had a sensitivity and specificity of 70% and 80%, respectively; a value of 600 IU/L or greater had sensitivity and specificity of 50% and 89%. Thus, serum LDH levels of 600 IU/L or greater are suggestive of histoplasmosis rather than PCP in appropriate clinical settings. Serum LDH may serve as an adjunct laboratory marker in the diagnosis of histoplasmosis. Elevated levels may prompt the physician to look for a diagnosis other than PCP early in the course of the illness.

Histoplasma capsulatum is a thermally dimorphic ascomycete that is a significant cause of respiratory and systemic disease in mammals including humans, especially immunocompromised individuals such as AIDS patients. As an environmental mold found in the soil, it is a successful member of a competitive polymicrobial ecosystem. Its host-adapted yeast form is a facultative intracellular pathogen of mammalian macrophages. H. capsulatum faces a variety of environmental changes during the course of infection and must survive under harsh conditions or modulate its microenvironment to achieve success as a pathogen. Histoplasmosis may be considered the fungal homolog of the bacterial infection tuberculosis, since both H. capsulatum and Mycobacterium tuberculosis exploit the macrophage as a host cell and can cause acute or persistent pulmonary and disseminated infection and reactivation disease. The identification and functional analysis of biologically or pathogenically important H. capsulatum genes have been greatly facilitated by the development of molecular genetic experimental capabilities in this organism. This review focuses on responsiveness of this fungus to its environment, including differential expression of genes and adaptive phenotypic traits.

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals, who may develop a progressive disseminated form which is often fatal if it is untreated. In such patients, the detection of antibody responses for both diagnosis and follow-up may be of limited use, whereas the detection of Histoplasma capsulatum var. capsulatum antigens may provide a more practical approach. We have recently described an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection in patients' sera of a 69- to 70-kDa H. capsulatum var. capsulatum-specific antigen which appears to be useful in diagnosis. To investigate its potential for the follow-up of histoplasmosis patients during treatment, antigen titers in the sera of 16 patients presenting with different clinical forms of histoplasmosis were monitored at regular intervals for up to 80 weeks. Sera from four of five patients with the acute form of the disease showed rapid falls in antigenemia, becoming antigen negative by week 14 (range, weeks 10 to 16). Sera from four patients with disseminated histoplasmosis showed falls in antigen levels; three of them became antigen negative by week 32; the fourth patient became negative by week 48. In contrast, antigen titers in four of six AIDS patients with the disseminated form of the disease remained positive throughout follow-up. Sera from only one patient who presented with the chronic form of the disease were analyzed, and this individual's serum became antigen negative by week 9. The inhibition ELISA is shown to be of particular use in the monitoring of non-AIDS patients with the acute and disseminated forms of the disease and may complement existing means of follow-up.

The reliability of MYCO/F Lytic medium in the BACTEC 9240 blood culture system was evaluated by comparing its performance to that of the Isolator system for the recovery of fungi and to that of the ESP II system for the recovery of mycobacteria. Of 717 specimens of blood cultured for fungi, 24 were positive; 12 samples were positive with both systems, 7 samples were positive with the Isolator system only, and 5 samples were positive with MYCO/F Lytic medium only. Fourteen samples grew Histoplasma capsulatum; both systems detected H. capsulatum in seven samples but the Isolator system alone detected H. capsulatum in seven samples. The mean times to the detection of H. capsulatum were 8 days (range, 4 to 13 days) for MYCO/F Lytic medium and 9 days (range, 6 to 18 days) for the Isolator system; the mean times to identification were 20 days (range, 15 to 24 days) for isolates recovered with MYCO/F Lytic medium and 11 days (range, 6 to 18 days) for those recovered with the Isolator system (P < 0.05). Cryptococcus neoformans was isolated from 10 fungal cultures; five isolates grew in both systems, and five isolates grew in MYCO/F Lytic medium only. The mean times to detection of C. neoformans were 4 days (range, 2 to 6 days) for MYCO/F Lytic medium and 7 days (range, 5 to 7 days) for the Isolator system (P < 0.05); the mean times to identification were 15 days (range, 7 to 27 days) for isolates recovered with MYCO/F Lytic medium and 8 days (range, 7 to 11 days) for those recovered with the Isolator system. Of the 687 samples of blood cultured for mycobacteria, 64 blood samples from 42 patients grew mycobacteria (58 grew Mycobacterium avium complex, 4 grew Mycobacterium kansasii, and 2 grew Mycobacterium tuberculosis); 42 isolates were recovered with both systems, 18 were isolated with MYCO/F medium only, and 4 were isolated with the ESP II system only alone (P < 0.05). The mean time to detection of mycobacteria with MYCO/F Lytic medium was 14 days, whereas it was 17 days with the ESP II system (P < 0.05). In summary, the combination of MYCO/F Lytic medium and the BACTEC 9240 instrument is an excellent blood culture system for the growth and detection of mycobacteria. A valid assessment of MYCO/F Lytic medium with regard to fungal isolation, however, was not possible due to the small number of isolates recovered.

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals living or travelling in areas of endemicity, who, without antifungal therapy, may develop a progressive disseminated fatal infection. For such patients, the detection of antibody responses by immunodiffusion or complement fixation test is of limited use. In contrast, the detection of Histoplasma capsulatum circulating antigens may provide a more practical approach to the rapid diagnosis of the disease. Accordingly, an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection of a 69- to 70-kDa H. capsulatum-specific determinant and incorporating a species-specific murine monoclonal antibody was developed. With sera from patients with different forms of the disease (n = 35), the overall sensitivity of the test was found to be 71.4%, while the specificity was found to be 98% with normal human sera from areas of endemicity (n = 44) and 85.4% with sera from patients with other chronic fungal or bacterial infections (n = 48). This novel, highly specific ELISA provides a significant addition to the existing diagnostic tests for the detection of histoplasmosis.

A yeast-phase-specific gene, yps-3, has been identified in the virulent Histoplasma capsulatum strain, G217B. Although DNA sequencing of the genomic yps-3 gene from G217B failed to detect homologies with known proteins, the 5' end of a yps-3 cDNA contained a consensus signal sequence. A 519-bp fragment of the cDNA containing the translational stop codon was linker modified and inserted into the bacterial expression vector, pATH 1. Escherichia coli extracts containing the pATH 1 vector alone expressed a major 34-kDa TrpE polypeptide following induction with indoleacrylic acid, while the pATH 1/yps-3 construct produced a predominant 54-kDa TrpE/yps-3 fusion protein. Polyclonal rabbit sera directed against G217B reacted exclusively with the 54-kDa fusion protein in Western blots (immunoblots); serum samples from three patients with acute pulmonary or disseminated histoplasmosis were also positive. To localize the yps-3 protein within G217B, a monoclonal antibody (MAb 7.1) which recognized the yps-3 portion of the fusion protein was generated. A 17.4-kDa protein was detected with MAb 7.1 in Western blots prepared from cell wall fractions of G217B; cytoplasmic fractions were unreactive. No yps-3 antigen was detected in either fraction of the Downs strain, which fails to express the yps-3 gene. MAb 7.1 also detected a 17.4-kDa antigen in ethanol-precipitated culture supernatants derived from G217B. These findings localize the yps-3 gene product to the cell wall and culture supernatants, where the protein may influence the phase transition or the maintenance of the yeast state.

Blastomyces dermatitidis (dog isolate T-58) yeast phase lysate antigen was concentrated and separated by Rotofor preparative isoelectric focusing cell (Bio-Rad). The pH values of the fractions were determined and equilibrated to pH 7.2 and then analysed by enzyme-linked immunosorbent assay using horseradish peroxidase enzyme system against serum specimens from dogs with blastomycosis, histoplasmosis, aspergillosis, and coccidioidomycosis. The results showed a peak absorbance at pH 3.89-4.31 (fractions 4 and 5) with the blastomycosis serum specimens. This was a single sharp peak while the rest of the fractions were lower. In contrast the sera from dogs with histoplasmosis showed a peak absorbance at pH 5.54-5.97 (fractions 9 and 10), while the other mycoses showed patterns that did not resemble the blastomycosis or histoplasmosis specimens. Serum specimens from dogs with blastomycosis being treated with itraconazole were also assayed (pre-treatment and 1, 2, 3, and 12 months post-treatment sera). The characteristic peak for blastomycosis was observed and a decrease in the peak was seen as the treatment progressed. Fractions 3-12 were also used to detect delayed dermal hypersensitivity in hyperimmunized hairless guinea-pigs. Fraction 5 (pH 4.31) elicited the optimal response in B. dermatitidis-immunized animals, while no cross-reactivity was observed in guinea-pigs sensitized with Histoplasma capsulatum killed cells.

The aim of this study was to determine the value of blood culture as a parameter of treatment effectiveness in experimental histoplasmosis. A total of thirty five hamsters, weighing approximately 120g, were inoculated intracardially with 0.1 ml of a suspension containing 4 x 10(7) cells/ml of the yeast phase of H. capsulatum. Treatments were started one week after the infection and lasted for 3 weeks. The azoles, (itraconazole, saperconazole and fluconazole) were administered once a day by gavage, at a dose of 8 mg/kg; Amphotericin B was given intraperitoneally every other day at a dose of 6mg/kg. Blood samples (1 ml) were obtained by heart punction from the 4th day after infection and were seeded in Sabouraud honey-agar and BHI-agar. The hamsters that survived were killed one week after treatment completion and the following criteria were considered for treatment evaluation: 1) rate of spontaneous death, at the end of the experience; 2) microscopic examination of Giemsa smears from liver and spleen and 3) determination of CFU in spleen cultures. Amphotericin B was the most effective drug, with negative blood cultures at day 20, negative spleen cultures in all cases and all the animals survived until the end of the study. Fluconazole was the less effective drug, blood cultures were positive during the whole experience, spleen cultures showed a similar average of CFU when compared with the control animals and 42.8% of these animals died. Saperconazole and itraconazole showed a similar activity, with survival of all hamsters and negative blood cultures at 23 and 26 days respectively. Blood culture seems to be valuable parameter for treatments' evaluation in experimental histoplasmosis of the hamster.

A prospective study was carried out in two groups of individuals: a group 1 (n = 40) included workers from a poultry farm, with potential occupational risk of exposure to Histoplasma capsulatum, etiologic agent of histoplasmosis, and a group 2 (n = 16), persons without occupational risk of exposure to the agent. Histoplasmin skin test was performed in both groups, and three sera were obtained from each individual: 1) before skin test was done, 2) 30 days after, and 3) 180 days after it. In both groups the histoplasmin skin test, even when the test was positive, was not a sufficient antigenic booster to provoke an increase in the H. capsulatum antibody levels capable to be detected by the serologic tests used (ELISA and Double Immunodiffusion). These results contribute to improve the interpretation of ELISA test values in the diagnosis of histoplasmosis.

We sought to determine whether measurement of Histoplasma capsulatum var. capsulatum antigen concentration in tissues and blood provided a marker for antifungal effect of itraconazole in a nonlethal murine model of histoplasmosis. Treatment with itraconazole (Sporanox), in cyclodextrin, was evaluated in a pulmonary model of histoplasmosis. Mice infected with 4.0 x 10(7) yeast-phase organisms by endotracheal inoculation were treated with itraconazole, 1.5 mg twice daily by gavage, for 10 consecutive days, beginning on day 4 of infection. All mice were sacrificed on day 15 of infection. Blood, spleen, and lung tissues were removed for culture and quantification of antigen. Numbers of organisms were significantly lower in spleens from the treated group: 20.8 +/- 41.8 vs. 65.8 +/- 39.1 in the control group, P = 0.017. Numbers of organisms in lung were 9.6 +/- 27.3 colony forming units in treated versus 24.2 +/- 36.3 in control animals, P = 0.267. Antigen concentrations in spleen tissue and serum were lower in treated versus control mice: spleen, 1.8 +/- .6 units in treated versus 11.0 +/- 2.3 in controls, P < 0.001; serum, 0.8 +/- 0.2 units in treated versus 2.2 +/- 1.0 units in controls, P < 0.001. Lung antigen concentrations were similar in the two groups, 19.2 +/- 1.4 units in treated compared to 17.9 +/- 3.0 units in control mice, P = 0.142. The cyclodextrin formulation of itraconazole (Sporanox) demonstrated antifungal activity in experimental histoplasmosis. Antigen detection was a useful marker for antifungal effect.

A study to screen for the syndrome of presumed ocular histoplasmosis (SPOH) among native populations from three Mexican states was performed. Two of these states, Guerrero and Querétaro, were selected as histoplasmosis is endemic there, whereas Tlaxcala was considered a control, due to the absence of reported cases. A total of 253 individuals were submitted to ocular fundus examination to obtain evidence of SPOH. A high percentage of positive reactors to histoplasmin skin test (ST) was observed in Guerrero (83%) and Querétaro (53%), whereas in Tlaxcala positive ST were almost absent (2.04%). Only five individuals had retinal lesions, although these lesions were not characteristic of the syndrome. Stimulation of these individual's cells showed different patterns in the histoplasmin-induced lymphocyte transformation response, and two out of five individuals with retinal lesions presented a stimulated response, as well as three controls without lesions. Histocompatibility antigens (HLA) were determined in a sample of each population and no particular allele, including HLA-B7, was found to be related to SPOH as reported in the USA; however, HLA-B22 was found in three individuals who developed pulmonary histoplasmosis. Results do not provide clinical evidence or data on specific HLA risk factors, for the presence of SPOH in the population studied.

An indirect micro-ELISA system is presented for diagnosing histoplasmosis. The diagnostic criteria are defined by using sera from 12 patients who are histoplasmosis carriers. For this group, the optical density values were superior to 1,000; use was made of 43 sera from blood bank donors and 9 sera from children without a history of exposure. The optical density values in these cases were inferior to 0,200. The significant difference found led to the diagnostic criterion for confirming 3 histoplasmosis carriers who showed clinical manifestations but had been negative to double immunodiffusion. Thus, the usefulness of the proposed micro-ELISA system for early diagnosis was proved.

We report the recovery of Histoplasma capsulatum from blood specimens cultured for Mycobacterium sp. in BACTEC 13A radiometric medium. H. capsulatum was recovered from six of eight blood specimens submitted for mycobacterial cultures from five human immunodeficiency virus-positive individuals. Initial positive metabolic signals occurred at a mean of 11 days, but no organisms were detected with acid-fast stains. The bottles remained positive, and after an additional incubation (mean, 8 days), yeast cells morphologically compatible with H. capsulatum were detected when aliquots were stained with acridine orange. Therefore, when radiometric mycobacterial blood cultures with persistent positive metabolic signals and negative acid-fast stains are encountered, acridine orange staining and subculturing for a variety of microorganisms, including fungi, e.g., H. capsulatum, should be considered.

Although the detection of fungemia has been improved by the use of vented or biphasic blood culture bottles, the best recovery and earliest detection have been reported in the Isolator lysis-centrifugation system. It was recently demonstrated that improved detection of both bacteria and fungi was accomplished by mechanically agitating blood culture bottles for the first 24 h of incubation. In this study the detection of fungemia by use of the Isolator system was compared with that of an agitated biphasic system. A total of 182 fungi were isolated from blood specimens inoculated into both culture systems. No difference in the overall recovery of fungi or individual species of yeasts was observed between the two systems. However, all seven isolates of Histoplasma capsulatum were recovered in the Isolator system only. The time required to detect fungemia with each of the two systems was also compared. No statistically significant difference was observed. From the data collected during this 18-month study, it can be concluded that the overall recovery and time of detection of yeasts are equivalent in the lysis-centrifugation system and the agitated biphasic blood culture system. The lysis-centrifugation system is still superior for the detection of filamentous fungi such as H. capsulatum.

A 29-year-old man who had been abroad for several years (mainly Mexico) fell ill with fever (up to 39.8 degrees C), night sweats, weight loss of 10 kg in 6 months (height 181 cm, weight 50.5 kg) and abdominal pain. Computed tomography of the abdomen revealed many enlarged abdominal lymph nodes. Serological tests were positive for HIV antibodies. Fine-needle biopsy of one of the enlarged lymph nodes revealed numerous macrophages with round inclusions, typical for Histoplasma capsulatum. Disseminated histoplasmosis was confirmed by direct antigen demonstration in serum and urine. The patient's serious clinical condition clearly improved and lymph node enlargement regressed after starting specific i.v. treatment with amphotericin B (initially 20 mg/dl, then 50 mg/dl). Although complete cure of the histoplasmosis in connection with the HIV infection is not to be expected, the patient has remained without symptoms for four months on 50 mg weekly of amphotericin B i.v., later changed to imidazole derivatives (400 mg ketoconazole or 200 mg itraconazole, respectively.

In areas where Histoplasma capsulatum infections are endemic in the United States, there is an increasing frequency of progressive disseminated histoplasmosis (PDH) as an opportunistic infection in patients with acquired immune deficiency syndrome (AIDS). The bone marrow and peripheral blood (PB) specimens in 13 patients with AIDS and PDH were reviewed. Anemia, leukopenia, and thrombocytopenia were found in 12, 10, and 7 patients, respectively. Circulating organisms were detected in the blood smears or buffy coat preparations from five patients and were associated with PB nRBCs and severe absolute monocytopenia. Morphologically, the marrow specimens showed one of four patterns: (1) no morphologic evidence of infection (two patients, one with a positive marrow culture); (2) discrete granulomas (two patients, both with positive marrow cultures); (3) lymphohistiocytic aggregates (six patients, four with positive marrow cultures); and (4) diffuse macrophage infiltrates (three patients, all with positive marrow cultures). Morphologic examination of the bone marrow combined with cultures is useful in diagnosing disseminated histoplasmosis in patients with AIDS. However, the morphologic findings in the bone marrow may be different in patients with AIDS compared with non-AIDS patients, and seemingly nondiagnostic morphologic features must be approached with a high degree of suspicion in diagnosing infections with H. capsulatum in this population.

This paper reports the positive results obtained in the sera of 70 patients with histoplasmosis, the clinical presentation of the disease, and the possibilities for an appropriate follow-up of the clinical course of these patients by means of titers of the sera taken during the persistence of the signs and symptoms of the disease and following its resolution. The most frequent clinical presentation was acute pulmonary disease and the single m precipitation band was found in a higher number of sera than the association of h and m bands. The authors report a case diagnosed as acute pulmonary histoplasmosis, that 9 months after a clinically and serologically negative continuum showed again precipitation bands and Histoplasma capsulatum was isolated from his oral mucosa lesions. The significance of serologic follow-up in patients with histoplasmosis until their total negativization and the feasibility of this follow-up by means of the titering of sera by the counterimmune electrophoresis technique.

Demonstration of Histoplasma capsulatum in conventional films of peripheral blood establishes the diagnosis of disseminated histoplasmosis. We describe two new examples of this pnenomenon and tabulate relevant data from 11 similar cases.

A patient with disseminated histoplasmosis, eosinophilia, and transient mesangiopathic glomerulonephritis stimulated a search for the presence of circulating immune complexes. Serum samples obtained on the fifth and 11th hospital days were strongly positive for ciculating immune complexes by both the Raji cell radioassay and the C1q solid phase assay. During the course of complete clinical recovery without therapy, both assays were weakly positive for circulating immune complexes on day 33. On day 56 they were negative. Using this case as a prototype, possible mechanisms for the renal immunopathology and the eosinophilic response are discussed with reference to the immunological perturbations thay may be observed in systemic mycotic infection.

Factors modulating host resistance to Histoplasma capsulatum are only partially understood. The role of iron-binding proteins in infectious diseases has been an area of recent in-depth investigation. The present study reaffirmed the necessity of iron for growth of H. capsulatum. Transferrin saturation was found to be of importance in withholding iron, and antigen-specific antibody had no added effect. Serums of patients with various clinical classes of histoplasmosis were found to exhibit abnormalities in iron metabolic parameters. However, based on transferrin saturation data, iron withholding by transferrin does not appear to be a significant host defense mechanism in vivo. Further studies presented herein suggest a protective effect of phagocytosis and sequestration by the macrophage-phagocyte system.

Five patients with African histoplasmosis were treated with ketoconazole. Three of these were children with disseminated disease and 2 were adults with localized cutaneous disease. Both patients with cutaneous disease responded to treatment, although one was lost to follow-up. Of the 3 children with disseminated disease, one was apparently cured, one responded well but subsequently relapsed, and one failed to respond in spite of having blood levels of ketoconazole within the therapeutic range. Further studies are needed to determine the optimum dosage and duration of treatment with ketoconazole for this condition.

A model of disseminated histoplasmosis in CBA/J mice was developed. Cultures of Histoplasma capsulatum from the spleens of infected mice suggested almost complete clearance of fungi by week 3. The adherent spleen cells from infected mice showed a 2- to 20-fold increase in fibrinolysis. The increase in activity was maximal around 1 to 2 weeks and disappeared after week 3 of infection, and this paralleled the progressively decreasing number of culturable fungi from the spleen. In vitro coculture of infected spleen cells or nylon wool-purified immune T cells and proteose peptone-induced macrophages resulted in increased fibrinolysis. Peritoneal exudate cells from infected mice also showed increased fibrinolysis. The addition of soluble antigen to an in vitro culture system resulted not only in an increase in fibrinolytic activity of peritoneal exudate cells derived from infected mice but also of proteose peptone-induced macrophages. These observations suggest that spleen and peritoneal macrophages from H. capsulatum-infected mice exhibit increased fibrinolysis which in turn is indicative of macrophage activation. The mechanism of activation occurs as a result of immunologically specific T cell-macrophage interaction and by the action of histoplasma products on the macrophages. The significance of these findings and the role of the plasminogen activator assay in studies of disseminated fungal infection are discussed.