Paracoccidioidomycosis: an update

Paracoccidioidomycosis associated with human immunodeficiency virus infection. Report of 10 cases

We describe here the epidemiological and clinical characteristics of 10 HIV-infected patients with paracoccidioidomycosis. All patients were adult males from small towns in Brazil and had a previous history of work or residence in a rural area. The two infections were diagnosed concomitantly in six of the ten patients, and for six of the patients, the mycosis was the first clinical manifestation of HIV infection. Risk factors for HIV infection were injection drug use in some patients and multiple sexual partners in others. Six patients died and autopsy revealed severe disseminated paracoccidioidomycosis in three. Exuberant and severe clinical pictures suggest an alteration in the natural history of this mycosis as a result of HIV immunosuppression. The frequency of paracoccidioidomycosis in the HIV-infected population is not known to differ from that reported for this mycosis in non-HIV patients.

Paracoccidioidomycosis and larynx carcinoma

Report of a case of paracoccidioidomycosis associated with a carcinoma: both located in the larynx in a patient whose therapeutic response to antifungal treatment produced a recovery of physical conditions. This case shows the importance of taking into account the diagnosis of paracoccidioidomycosis in all patients with problems in the larynx, especially those who inhabit or inhabited endemic areas of Paracoccidioides brasiliensis.

Combined use of Paracoccidioides brasiliensis recombinant 27-kilodalton and purified 87-kilodalton antigens in an enzyme-linked immunosorbent assay for serodiagnosis of paracoccidioidomycosis

The diagnosis of paracoccidioidomycosis (PCM) has relied on the identification of the host's humoral response by using a variety of immunological methods, such as complement fixation and immunodiffusion. Although these approaches are useful, historically their sensitivity and specificity have often been compromised by the use of complex mixtures of undefined antigens. The use of combinations of purified, well-characterized antigens appears preferable and may yield optimum results. Accordingly an indirect enzyme-linked immunosorbent assay (ELISA) using combinations of the previously described 27-kDa recombinant antigen and the 87-kDa heat shock protein were used for diagnosis and follow-up of patients with PCM. A total of 37 patients classified according to their clinical presentations (7 with the acute or subacute form of the disease, 22 with the chronic form of the disease, and 8 with the chronic unifocal form) were studied. Eighteen of these patients were also evaluated at every follow-up appointment. Forty serum samples from patients with other diseases and 50 serum samples from healthy individuals were also studied. Detection of anti-27-kDa and anti-87-kDa antibodies in sera of patients with PCM by ELISA using a combination of the two purified proteins showed a sensitivity of 92% with a specificity of 88% in comparison with normal human sera and 90% in comparison with the heterologous sera. These results demonstrated a significant increase in sensitivity and specificity compared to results when the antigens were used separately. Thus, the use of combinations of well-defined antigens appears to offer clear advantages over the use of single antigens when diagnosing PCM.

Thymus invasion and atrophy induced by Paracoccidioides brasiliensis in BALB/c mice

Literature has shown that immunosuppression observed in systemic mycosis can be related to damage in primary lymphoid organs. We have studied the immunopathological alterations induced experimentally by Paracoccidioides brasiliensis in these organs. In this work, thymic alterations induced in BALB/c mice during acute and chronic stages of infection are described. It was observed that P. brasiliensis is able to invade the thymic microenvironment, inducing severe atrophy characterized by degeneration of the cortical area, organ weight decrease, loss of corticomedullary delimitation and increase in histiocyte number. Occurrence of polymorphonuclear infiltration in the subcapsular area was also observed. Our results demonstrate that P. brasiliensis induces profound thymic atrophy and raises the question of whether this could be a fungal strategy to achieve successful establishment in the host over the long term.

The trend of imported mycoses in Japan

Pathogenic fungi that are non-native in Japan are highly virulent and present a significant health hazard to persons in the environment into which they are introduced. Little is known, however, about the precise trend of infection by imported mycoses in Japan. To clarify this issue, all available cases were collected through a search of MEDLINE and Japana Centra Revuo Medicine and analyzed. Also included in this analysis were cases not reported in the literature for which the authors provided identification of the fungi, diagnosis, or treatment. The analysis revealed that, for three diseases, the number of imported mycoses cases in Japan is much higher than previously reported: 31 cases of coccidioidomycosis, 34 cases of histoplasmosis, and 17 cases of paracoccidioidomycosis. Additionally, one case of penicilliosis marneffei was found. The most rapid increase in the incidence of these mycoses occurred from 1991 to 1995. Analysis of the patients' profiles provided the following information: (1) coccidioidomycosis infection in Japan is increasing very rapidly, (2) Japan might be an endemic area of histoplasmosis infection, (3) histoplasmosis is a potentially fatal disease; and (4) reliable serodiagnostic methods have been used only infrequently. Because of the increase of international travel and immigration, the incidence of imported mycoses in Japan is expected to continue rising, and mycoses that have never been reported in Japan, such as blastomycosis, might also be encountered in the near future. To cope with this newly emerging health problem to residents of Japan, the Japanese medical system must train its members to identify and treat mycoses.

[Prevalence of paracoccidioidomycosis infection determined by sorologic test in donors' blood in the Northwest of Paraná, Brazil]

In this paper the classical ELISA test was used, which is a highly sensitive method, with the objective of estimating the anti-Paracoccidioides brasiliensis antibodies level in healthy people, residing in supposedly endemic regions for PCM, Northwest Paran State, Brazil. The sera was analyzed from 680 blood donors' who were approved by the classical serologic screening by blood banks. Four cities were studied (Campo Mour o, Maring , Cianorte and Umuarama) with a sample of 170 donors each. The antigen used was Ag7days, diluted serum 1/400, anti human IgG-conjugate marked with peroxidase and revealed with O-Phenylenediamine. It was possible to detect 181 (27%) sera with antibody level above the cut off threshold. The percentage varied between the cities. These results allied with the favorable climatic and geographical conditions and also previous reports of PCM indigenous to the region, indicate that the Northwest of Paran is an endemic region for PCM.

Production of pro-inflammatory cytokines during the early stages of experimentalParacoccidioides brasiliensisinfection

Pro-inflammatory cytokines play an important role in both recruitment and activation of leukocytes migrating into tissues in response to invading pathogens. In this study the production of pro-inflammatory cytokines, determined by ELISA assays, and the recruitment of leukocytes into the lungs of BALB/c mice infected with Paracoccidioides brasiliensis conidia were evaluated during the early stages of infection. The results showed that infected mice had a significant increase in leukocytes in the lung during the first 4 days with a peak at day 2 post-challenge; infiltrates were composed mainly of polymorphonuclear neutrophils (PMN). Pro-inflammatory cytokines such as tumour necrosis factor alpha (TNF-alpha), interleukin (IL) 6, IL-1beta and macrophage inflammatory protein (MIP) 2 were produced at elevated levels during the first 4 days post-challenge, but only in pulmonary samples and not in sera. Additionally, during the early stages of infection, overall weight loss was recorded in infected mice. These results suggest that pro-inflammatory cytokines could be responsible for the recruitment of leukocytes into the lung during the early stages of P. brasiliensis infection. In addition, both pro-inflammatory cytokine production and leukocyte recruitment may participate in the control of infection by influencing the organization of the immune response in the host exposed to P. brasiliensis conidia.

Immunity and hypersensitivity to gp43 antigen in susceptible and resistant mice infected withParacoccidioides brasiliensis

Pathogenic mechanisms underlying paracoccidioidomycosis are still poorly understood. A well-established murine model of resistance (mouse lineage A/Sn) and susceptibility (lineage B10.A) to P. brasiliensis pulmonary infection was here employed to compare immune response to gp43, the major antigenic component of the fungus. Mice were infected and their cellular and humoral immunity to gp43 were investigated for up to 16 weeks. In both mouse strains, challenge with gp43 indistinguishably evoked a typical immediate-hypersensitivity response, followed by a 24-h late-phase reaction consistent with the same type of immunological activation. IL-4 was detected in cultures of gp43-stimulated lymph node cells only in susceptible animals 2 weeks post-infection, while IL-5 was found throughout the study in both mouse strains. IL-10 appeared in the supernatants of stimulated cells from resistant and susceptible animals in increasing amounts as infection advanced. Conversely, interferon (IFN)-gamma was produced under gp43 stimulation only by cells from A/Sn animals. The humoral response was characterized by low levels of anti-gp43. Titration of IgG isotypes, however, revealed a predominance of IgG1. IgG2a levels were highest in resistant animals, whereas IgG2b levels were highest in susceptible mice. In conclusion, immunity induced by gp43 exhibits common features in A/Sn and B10.A phenotypes, such as immediate hypersensitivity, late phase reaction and high levels of IL-10, but some differences between the strains are also seen.

Paracoccidioidomycosis: report of 2 cases mimicking squamous cell carcinoma

Paracoccidioidomycosis is an endemic fungal infection in Latin America. This mucocutaneous disease often involves the oral mucosa and may clinically resemble other infectious and neoplastic processes. Paracoccidioidomycosis that clinically suggested squamous cell carcinoma was diagnosed in 2 patients with a history of heavy alcohol and tobacco use. Antifungal therapy with ketoconazole and itraconazole resulted in resolution of the oral lesions. Interestingly, 1 patient had a pulmonary lesion that persisted after antifungal therapy, and biopsy proved this to be a squamous cell carcinoma of the lung.

Histopathologic and histochemical characterization of calcified structures in hamsters inoculated with Paracoccidioides brasiliensis

In pathogenicity studies of 31 Paracoccidioides brasiliensis isolates preserved using Castellani's method we intraperitoneally inoculated 104 young adult hamsters and found laminated concentric structures and calcified appearance that resembled Schaumann bodies, in 43 of them, especially in animals with apparently good condition. We characterized these structures histologically and histochemically using different stains (PAS, Grocott, haematoxylin-eosin, Von Kossa). The Von Kossa staining revealed calcium in these structures. Similar structures have been described in patients with sarcoidosis and also in hamsters inoculated with P. brasiliensis. We found no correlation between the presence of these calcifications and serum calcium levels.

Characterization of a chaperone ClpB homologue of Paracoccidioides brasiliensis

We report the cloning and sequence analysis of a genomic clone encoding a Paracoccidioides brasiliensis ClpB chaperone homologue (PbClpB). The clpb gene was identified in a lambda Dash II library. Sequencing of Pbclpb revealed a long open reading frame capable of encoding a 792 amino acid, 87.9 kDa protein, pI of 5.34. The predicted polypeptide contains several consensus motifs of the ClpB proteins. Canonical sequences such as two putative nucleotide-binding sites, chaperonins ClpA/B signatures and highly conserved casein kinase phosphorylation domains are present. ClpB is 69% to 49% identical to members of the ClpB family from several organisms from prokaryotes to eukaryotes. The transcript of PbclpB was detected as a mRNA species of 3.0 kb, preferentially expressed in the yeast parasitic phase of the fungus. A 89 kDa protein was also detected in yeast cells of P. brasiliensis.

In vitro comparison of activities of terbinafine and itraconazole against Paracoccidioides brasiliensis

In vitro, terbinafine is highly active against a broad spectrum of pathogenic fungi. We evaluated the activities of terbinafine and itraconazole against 31 isolates of Paracoccidioides brasiliensis. The tests were conducted by using a broth macrodilution procedure. MICs, in micrograms per milliliter, were as follows: terbinafine, 0.015 to 1.0 (geometric mean, 0.1188); itraconazole, 0.007 to 0.5 (geometric mean, 0.03165). The usual therapy for paracoccidioidomycosis is sulfonamides, amphotericin B, and azole derivatives (ketoconazole, itraconazole, and fluconazole). In comparison to amphotericin B, azole derivatives allow shorter treatment courses, can be administered orally, and are equally effective. Itraconazole has as high efficacy as ketoconazole, but with superior tolerance. It is the current drug of choice for treatment of paracoccidioidomycosis. The data obtained in this study indicate that terbinafine is active against P. brasiliensis in vitro and suggest that this allylamine can be considered a new option as drug therapy for paracoccidioidomycosis.

Characterization of B-1b cells as antigen presenting cells in the immune response to gp43 from Paracoccidioides brasiliensis in vitro

Antigen presentation is an essential stage in the development of immune response to a specific antigen. This response can lead to the production of antibodies and/or effector T lymphocyte activation. Macrophages, dendritic cells and B-lymphocytes, among others, act as antigen presenting cells. B-lymphocytes capture antigenic particles through a surface receptor of IgM nature. The interaction IgM-antigen leads to endocytosis of the complex and antigen processing which culminates in presentation of the antigen on the cell surface associated with a class II MHC molecule. At least three B cell subsets, B-1a (Ly-1B), B-1b and B-2, are present in the mouse periphery. B-1a and B1-b cells represent a small population in the adult spleen and are abundant in the peritonial and pleural cavities. It has been demonstrated in our laboratory that B-1b cells spontaneously proliferated in stationary cultures of adherent peritonial cells. Further, that these cells migrate to a non-specific inflammatory focus. Based on these findings, we investigated whether these cells are antigen presenting cells in vitro using as antigenic stimulus gp43 from Paracoccidioides brasiliensis. Results showed that B1-b cells express constitutively high levels of class II MHC and costimulatory molecules inducing an efficient proliferation of gp43 sensitized T lymphocytes.

Characterization of a gene which encodes a mannosyltransferase homolog of Paracoccidioides brasiliensis

We screened an expression library of the yeast form of Paracoccidioides brasiliensis with a pool of human sera that was pre-adsorbed with mycelium, from patients with paracoccidioidomycosis (PCM). A sequence (PbYmnt) was obtained and characterized. A genomic clone was obtained by PCR of P. brasiliensis total DNA. The sequence contained a single open reading frame (ORF) encoding a protein of 357 amino acid residues, with a molecular mass of 39.78 kDa. The deduced amino acid sequence exhibited identity to mannosyl- and glycosyltransferases from several sources. A DXD motif was present in the translated gene and this sequence is characteristic of the glycosyltransferases. Hydropathy analysis revealed a single transmembrane region near the amino terminus of the molecule that suggested a type II membrane protein. The PbYmnt was expressed preferentially in the yeast parasitic phase. The accession number of the nucleotide sequence of PbYmnt and its flanking regions is AF374353. A recombinant protein was generated in Escherichia coli. Our data suggest that PbYmnt encodes one member of a glycosyltransferase family of proteins and that our strategy was useful in the isolation of differentially expressed genes.

Correlation of factor XIIIa+ dermal dendrocytes with paracoccidioidomycosis skin lesions

We demonstrated and quantified by immunohistochemistry the factor XIIIa+ dermal dendrocytes (FXIIIa+ DD) in paracoccidioidomycosis skin lesions. Sixty-one biopsies were classified according to the tissue response in well-organized granulomas (group 1), poorly organized granulomas (group 2) and samples showing both kinds of granuloma (group 3). Ten biopsies from normal skin were used as controls. In order to verify the internalization of Paracoccidioides brasiliensis antigens by FXIIIa+ DD, we performed a double immunostaining technique. FXIIIa+ DD were hypertrophied with prominent dendrites and their number in the test groups was higher than in the control group, especially in the dermal papillae. P. brasiliensis yeasts were seen within the cytoplasm of FXIIIa+ DD in 40% of the immunostained biopsies. We could correlate these findings with the probable role of FXIIIa+ DD as antigen-presenting cells in the pathogenesis of skin lesions in paracoccidioidomycosis.

Paracoccidioides brasiliensis-reactive antibodies in Brazilian blood donors

In a survey for primary paracoccidioidomycosis (PCM) infection (and not the clinical disease), two groups of blood donors were analyzed. One study group was drawn from donors living in a rural area where PCM is endemic, and the other group from urban residents of a large city, São Paulo. Anti-Paracoccidioides brasiliensis (Pb) specific antibodies (IgG) in sera were analyzed by ELISA, using crude Pb exoantigens (exoAg) and purified specific Pb 43 kDa glycoprotein (gp43). The results showed that 21% of 700 rural samples and 0.9% of 350 urban samples were positive for exoAg and gp43. To avoid cross-reactions, the sera were adsorbed first with Histoplasma capsulatum antigens and secondly with Leishmania amazonensis antigens. In the first adsorption with H. capsulatum, reactivity to gp43 fell to 12.8% in the rural group and to 0% in the urban group. In the succeeding adsorption with L. amazonensis, this reactivity fell to 12.3% in the rural group. There was a statistically greater proportion of persons with gp43-reactive antibodies in rural group than in the urban group, indicating that rural residents had frequently become exposed to Pb and contracted primary, subclinical PCM. The present report is the first epidemiological study using ELISA to detect antibodies against gp43 in blood donors.

Current status of nonculture methods for diagnosis of invasive fungal infections

The incidence of invasive fungal infections has increased dramatically in recent decades, especially among immunocompromised patients. However, the diagnosis of these infections in a timely fashion is often very difficult. Conventional microbiologic and histopathologic approaches generally are neither sensitive nor specific, and they often do not detect invasive fungal infection until late in the course of disease. Since early diagnosis may guide appropriate treatment and prevent mortality, there has been considerable interest in developing nonculture approaches to diagnosing fungal infections. These approaches include detection of specific host immune responses to fungal antigens, detection of specific macromolecular antigens using immunologic reagents, amplification and detection of specific fungal nucleic acid sequences, and detection and quantitation of specific fungal metabolite products. This work reviews the current status and recent developments as well as problems in the design of nonculture diagnostic methods for invasive fungal infections.

Dual role for nitric oxide in paracoccidioidomycosis: essential for resistance, but overproduction associated with susceptibility

Using a murine model of susceptibility and resistance to paracoccidioidomycosis, we have previously demonstrated that immunosuppression occurs in susceptible (B10.A), but not in resistant (A/Sn), mouse strains. Accumulating evidence shows that NO is involved in the induction of T cell immunosuppression during infection as well as in the killing of Paracoccidioides brasiliensis. In the present work, we focused on NO and other macrophage products that could be associated with resistance or susceptibility to paracoccidioidomycosis. A striking difference was related to NO and TNF production. Macrophages from B10.A mice produced high and persistent NO levels, while in A/Sn animals, TNF production predominated. In in vitro cultures, P. brasiliensis-infected macrophages from A/Sn mice also produced large amounts of TNF, while B10.A macrophages only produced NO. TNF production by B10.A macrophages appeared to be suppressed by NO, because the addition of aminoguanidine sulfate, an inducible NO synthase (NOS2) inhibitor, resulted in TNF production. These results suggested that enhanced TNF or NO production is associated with resistance and susceptibility, respectively. However, regardless of the mouse strain, NOS2-deficient or aminoguanidine sulfate-treated mice presented extensive tissue lesions with increased fungal load in lungs and liver compared with their controls. We conclude that NOS2-derived NO is essential for resistance to paracoccidioidomycosis, but overproduction is associated with susceptibility.

A case of imported paracoccidioidomycosis in a German legionnaire

We report on a case of the chronic form of paracoccidioidomycosis with swelling and ulcerations of the mouth in a German legionnaire who also suffered from a chronic bronchitis. The patient had worked for many years in Brazil, an area endemic for the disease. Infection due to Paracoccidioides brasiliensis was diagnosed in Germany, more than 10 years after the patient's return. Diagnosis was established by the presence of yeast cells with multipolar budding in the tissue of the oral lesion. Furthermore, the fungus was grown in a liquid Leishmania culture medium. Identification of the fungus was based on morphology and genetic sequencing. Furthermore, IgG antibodies against a 43-kDa antigen of P. brasiliensis were detected in a western blot. After itraconazole therapy (400 mg day(-1)) for 4 weeks, the lesions had disappeared almost completely, but the therapy was continued for further 5 months to avoid relapse of the infection.

Experimental paracoccidioides brasiliensis infection in mice: influence of the hormonal status of the host on tissue responses

We have previously proposed that 17beta-estradiol may be responsible in part for the decreased frequency of clinical paracoccidioidomycosis in females via a blocking of the initial morphological transformation necessary to initiate infection. Here we examined the course of infection in male and female mice in relation to their hormonal status. After pulmonary infection with conidia, normal males showed progressive infection, whereas normal females restricted proliferation and progressive disease. In contrast, castrated animals exhibited lesser capacity to restrict disease progression. Castrated male mice reconstituted with 17beta-estradiol initially restricted proliferation, but showed disease progression later in infection, whereas castrated female mice reconstituted with testosterone were unable to restrict disease. Quantitative histological analyses demonstrated that only normal male and castrated reconstituted mice developed granulomas, which decreased in number and size with time correlating with increasing numbers of CFU in the lungs. Greater numbers of chronic inflammatory foci did not correlate with higher CFU. These results further support a role for 17beta-estradiol during early innate resistance of females to paracoccidioidomycosis.

The oral route in the pathogenesis of paracoccidioidomycosis: an experimental study in BALB/c mice infected with P. brasiliensis conidia

Due to the high frequency of oral mucosal lesions observed in paracoccidioidomycosis patients, it was advocated that the infection was acquired by the traumatic implantation of the etiologic agent Paracoccidioides brasiliensis. Although at present this theory is considered invalid, it has not yet been excluded in experimental studies. In order to determine if intra-oral inoculation could explain the pathogenesis of paracoccidioidomycosis, 64 BALB/c mice were inoculated intra-orally with 850.000 viable P. brasiliensis conidia into the mandibular body. Animals were sacrificed at various time intervals up to 20 weeks and cultures were made from gingiva, lungs, spleen, and liver. Additionally, histopathological studies of the mandibular body were also performed. P. brasiliensis was isolated from all gingival tissues during the interval 24-72 h, indicating that the infection was active. During the 5-10 week period, the infection appeared to have been controlled at the inoculation site as cultures showed a significant reduction in colony forming units (CFU); however, at the 15-20 week period such control was lost and the fungus was recovered once more. Dissemination to other body sites was rare; thus, the lungs were involved in just one animal (2%), the liver in two (3%) and the spleen in seven (11%). The infection became established as proven by positive organ cultures, but the dissemination pattern did not correspond to the one observed in humans. Based on these findings, the intra-oral traumatic route does not appear to mimic the natural history of paracoccidioidomycosis.

Paracoccidioides brasiliensis 87-kilodalton antigen, a heat shock protein useful in diagnosis: characterization, purification, and detection in biopsy material via immunohistochemistry

The 87-kDa antigen derived from the fungal pathogen Paracoccidioides brasiliensis can be detected in the sera of infected patients, and its levels have been shown to correlate well with response to treatment and with clinical cure. Despite its potential importance, the antigen has been poorly characterized. The 87-kDa antigen was purified to homogeneity via preparative gel electrophoresis; N-terminal amino acid sequencing revealed substantial homology with heat shock proteins (hsps) from a variety of organisms. A monoclonal antibody (MAb) raised against a Histoplasma capsulatum 80-kDa hsp showed cross-reactivity to the purified 87-kDa antigen via Western blotting, and the 87-kDa-specific MAb P1B demonstrated that the antigen was expressed at higher levels in yeast than in mycelia by the same technique. Enzyme-linked immunosorbent assay and immunofluorescence reactivity using P1B confirmed increased expression of the 87-kDa antigen during the temperature-induced transformation of mycelia to yeast. Yeast-to-mycelium transformation was accompanied by a fall in expression, although the 87-kDa antigen was clearly constitutively expressed in both phases. Immunochemical staining of tissues from patients with MAb P1B who were infected with P. brasiliensis confirmed in vivo expression of the 87-kDa antigen by yeasts, and identification of this antigen via this method appears to be a useful adjunct to other methods used to diagnose paracoccidioidomycosis.

The pathobiology of Paracoccidioides brasiliensis

Paracoccidioides brasiliensis causes one of the most prevalent systemic mycoses in Latin America--paracoccidioidomycosis. It is a dimorphic fungus that undergoes a complex transformation in vivo, with mycelia in the environment producing conidia, which probably act as infectious propagules upon inhalation into the lungs, where they transform to the pathogenic yeast form. This transition is readily induced in vitro by temperature changes, resulting in modulation of the composition of the cell wall. Notably, the polymer linkages change from beta-glucan to alpha-glucan, possibly to avoid beta-glucan triggering the inflammatory response. Mammalian oestrogens inhibit this transition, giving rise to a higher incidence of disease in males. Furthermore, the susceptibility of individuals to paracoccidioidomycosis has a genetic basis, which results in a depressed cellular immune response in susceptible patients; resistance is conferred by cytokine-stimulated granuloma formation and nitric oxide production. The latency period and persistence of the disease and the apparent lack of efficacy of humoral immunity are consistent with P. brasiliensis existing as a facultative intracellular pathogen.

Parinaud'S oculoglandular syndrome associated with paracoccidioidomycosis

The authors report one case of Parinaud's oculoglandular syndrome associated with Paracoccidioides brasiliensis infection. No other medical report of this condition was found in the medical literature available at Index Medicus and Medline. The eye involvement has been rather uncommon in paracoccidioidomycosis and this report emphasizes the possibility of this kind of presentation making it also necessary to include paracoccidioidomycosis among the several known causes of Parinaud's oculoglandular syndrome.

Molecular cloning, characterization and expression of the heat shock protein 60 gene from the human pathogenic fungus Paracoccidioides brasiliensis

A gene encoding the heat shock protein (HSP) 60 from Paracoccidioides brasiliensis (Pb) was cloned and characterized. The hsp60 gene is composed of three exons divided by two introns. Structural analysis of the promoter detected canonical sequences characteristic of regulatory regions from eukaryotic genes. The deduced amino acid sequence of the Pb hsp60 gene and the respective cloned cDNA consists of 592 residues highly homologous to other fungal HSP60 proteins. The hsp60 gene is present as a single copy in the genome, as shown by Southern blot analysis. The HSP60 protein was isolated from Pb yeast cellular extracts. N-terminal amino acid sequencing of HSP60 confirmed that the cloned hsp60 gene correlated to the predicted protein in Pb. HSP60 expression appeared to be regulated during form transition in Pb, as different levels of expression were detected in in vitro labeling of cells and northern blot analysis. The complete coding region of Pb hsp60 was fused with plasmid pGEX-4T-3 and expressed in Escherichia coli as a glutathione S-transferase-tagged recombinant protein. The protein reacted with a mouse monoclonal antibody raised to a human recombinant HSP60. Western immunoblot experiments demonstrated that the recombinant protein and the native HSP60 were recognized by sera from humans with paracoccidioidomycosis (PCM).

Detection of melanin-like pigments in the dimorphic fungal pathogen Paracoccidioides brasiliensis in vitro and during infection

Melanins are implicated in the pathogenesis of several human diseases, including some microbial infections. In this study, we analyzed whether the conidia and the yeasts of the thermally dimorphic fungal pathogen Paracoccidioides brasiliensis produce melanin or melanin-like compounds in vitro and during infection. Growth of P. brasiliensis mycelia on water agar alone produced pigmented conidia, and growth of yeasts in minimal medium with L-3,4-dihydroxyphenylalanine (L-DOPA) produced pigmented cells. Digestion of the pigmented conidia and yeasts with proteolytic enzymes, denaturant, and hot concentrated acid yielded dark particles that were the same size and shape as their propagules. Immunofluorescence analysis demonstrated reactivity of a melanin-binding monoclonal antibody (MAb) with the pigmented conidia, yeasts, and particles. Electron spin resonance spectroscopy identified the yeast-derived particles produced in vitro when P. brasiliensis was grown in L-DOPA medium as a melanin-like compound. Nonreducing polyacrylamide gel electrophoresis of cytoplasmic yeast extract revealed a protein that catalyzed melanin synthesis from L-DOPA. The melanin binding MAb reacted with yeast cells in tissue from mice infected with P. brasiliensis. Finally digestion of infected tissue liberated particles reactive to the melanin binding MAb that had the typical morphology of P. brasiliensis yeasts. These data strongly suggest that P. brasiliensis propagules, both conidia and yeast cells, can produce melanin or melanin-like compounds in vitro and in vivo. Based on what is known about the function of melanin in the virulence of other fungi, this pigment may play a role in the pathogenesis of paracoccidioidomycosis.

Cerebriform colonies of Paracoccidioides brasiliensis isolated from nine-banded armadillos (Dasypus novemcinctus) at room temperature

Twelve isolates of Paracoccidioides brasiliensis generated cerebriform colonies at room temperature on potato glucose agar slants (PDA). These isolates contained abundant chlamydospores and yeast-like cells and are a subset of the 65 isolates obtained from nine-banded armadillos (Dasypus novemcinctus). They grew as a yeast form with typical multiple buddings at 37 degrees C on brain heart infusion agar supplemented with 1% glucose. After replating on PDA and culturing at room temperature for 2 months, the mutants appeared as cottonous colonies, which indicated that the morphological characteristics were unstable.

The habitat of Paracoccidioides brasiliensis: how far from solving the riddle?

When trying to understand the pathophysiology of any infectious agent, one key piece of information is the determination of its habitat. In the case of Paracoccidioides brasiliensis, the precise location of the fungus' environmental niche remains undefined despite the efforts of various research groups. This review summarizes recent studies on the ecology of P. brasiliensis and certain facets of paracoccidioidomycosis. Studies on the juvenile form of paracoccidioidomycosis in children less than 13 years of age, the characterization of the ecological factors in the 'reservarea' where the infection is acquired and the presence of P. brasiliensis in the nine-banded armadillo (Dasypus novemcinctus), are all helping to pinpoint the microniche of this pathogen. The application of molecular biology techniques based on the amplification of nucleic acids will also hopefully help in establishing the precise habitat of P. brasiliensis.

The low efficiency of dendritic cells and macrophages from mice susceptible to Paracoccidioides brasiliensis in inducing a Th1 response

In the present study we evaluated T cell proliferation and Th lymphokine patterns in response to gp43 from Paracoccidioides brasiliensis presented by isolated dendritic cells from susceptible and resistant mice. T cell proliferation assays showed that dendritic cells from susceptible mice were less efficient than those from resistant mice. The pattern of T cell lymphokines stimulated by dendritic cells was always Th1, although the levels of IL-2 and IFN-gamma were lower in T cell cultures from susceptible mice. To determine whether different antigen-presenting cells such as macrophages and dendritic cells stimulated different concentrations of Th1 lymphokines, the production of IFN-gamma and IL-2 was measured. It was observed that dendritic cells were more efficient than macrophages in stimulating lymphoproliferation in resistant mice. However, no significant difference was observed for IFN-gamma or IL-2 production. When cells from susceptible mice were used, macrophages were more efficient in stimulating lymphoproliferation than dendritic cells, but no difference was observed in the production of Th1 cytokine. Taken together, these results suggest the lower efficiency of dendritic cells and macrophages from B10.A mice in stimulating T cells that secrete Th1 lymphokines in vitro, an effect that may be involved in the progression of the disease in vivo.

Role of IL-10 in invasive aspergillosis: increased resistance of IL-10 gene knockout mice to lethal systemic aspergillosis

IL-10 is associated with a Th2 response, down-regulation of a Th1 response and macrophage activation. We assessed the role of IL-10 during systemic infection with Aspergillus fumigatus. Systemic aspergillosis was established in female C56B1/6 IL-10(-/-) (KO) and wild-type (WT) C57B1/6 mice by i.v. administration of 1 x 10(5)-6 x 10(5) conidia of A. fumigatus. In two experiments, KO survived longer than did WT (P < 0.001). Determination of fungal burdens in the kidneys and brain showed that KO carried significantly lower burdens in both organs than did WT on day 3 (P < 0.001). Semiquantitative histological analyses showed fewer inflammatory foci/mm2 in brain and kidneys of KO than WT (P < 0.03 and < 0.001, respectively) and that extent of infection and associated tissue injury were greater in WT. Although beneficial in some bacterial infections, exogenous IL-10 has been shown deleterious in models of fungal infection. Our data indicate IL-10 is deleterious during systemic aspergillosis infection, increasing the host susceptibility to lethal infection. We speculate this might be related to greater Th2 or lesser Th1 responses, or down-regulation of macrophage responses, in WT compared with KO.

Paracoccidioidomycosis: a model for evaluation of the effects of human immunodeficiency virus infection on the natural history of endemic tropical diseases

The interaction of human immunodeficiency virus (HIV) infection with endemic tropical diseases has become a major concern, but its mechanisms are still poorly understood. Paracoccidioidomycosis (PCM), a South America endemic deep mycosis, may provide an interesting model to investigate this interaction, as clinical-epidemiological features of most HIV-PCM-coinfected patients are difficult to classify into the standard acute and chronic forms of PCM. Such patients have presented clinical features indicative of an uncontrolled infection with lymphohematogenous dissemination, similar to the more severe, acute form. However, this infection probably resulted from reactivated latent foci that, in nonimmunocompromised hosts, leads to the less severe chronic form, characterized by mucosal lesions. We propose that a new outcome of the Paracoccidioides brasiliensis-host interaction is induced by concomitant HIV infection. This outcome probably reflects an impaired anti-P. brasiliensis immune response during coinfection that is similar to that seen in the acute form, although the patients have a chronic P. brasiliensis infection.

Comparative efficacy of fluconazole and amphotericin B in the parenteral treatment of experimental paracoccidioidomycosis in the rat

Patients with severe and complicated paracoccidioidomycosis are treated with amphotericin B by the intravenous route. Fluconazole is active in vitro against Paracoccidioides brasiliensis and can also be administered intravenously, but few clinical or experimental data are available about its action against the infection caused by this fungus. In the present study, the efficacy of fluconazole and amphotericin B was assessed comparatively in rats inoculated parenterally with P. brasiliensis. The treatment was performed 3 times a week for 4 weeks starting one week after infection. Fluconazole administered intraperitoneally (14 mg/kg body weight/dose) was more effective (P < 0.001) than amphotericin B (2 mg/kg body weight/dose) in reducing the number of colony forming units in the lungs and spleen. When administered intravenously at the dose of 3 mg/kg body weight, fluconazole was as effective as amphotericin B (0.8 mg/kg body weight) in reducing the pulmonary fungal burden. Under these conditions, the rats treated with fluconazole had a smaller number of colony forming units than untreated animals (P < 0.001), but amphotericin B was more effective than fluconazole in reducing spleen infection (P < 0.005). Except for this result obtained with a low dose, fluconazole showed an antifungal action equal to or higher than that of amphotericin B. The activity of fluconazole at doses equivalent to those used for human treatment suggests that this antifungal agent may be an alternative to amphotericin B for the early intravenous treatment of patients with paracoccidioidomycosis.

Central nervous system paracoccidioidomycosis. Report of a case successfully treated with itraconazol

Paracoccidioidomycosis (PCM) is a primary pulmonary infection that often disseminates to other organs and systems. Involvement of the central nervous system (CNS) is rare and due to the fact that both clinical alertness and establishment of the diagnosis are delayed, the disease progresses causing serious problems. We report here a case of neuroparacoccidioidomycosis (NPCM), observed in a 55 year-old male, who consulted due to neurological symptoms (left hemiparesis, paresthesias, right palpebral ptosis, headache, vomiting and tonic clonic seizures) of a month duration. Upon physical examination, an ulcerated granulomatous lesion was observed in the abdomen. To confirm the diagnosis a stereotactic biopsy was taken; additionally, mycological tests from the ulcerated lesion and a bronchoalveolar lavage were performed. In the latter specimens, P. brasiliensis yeast cells were visualized and later on, the brain biopsy revealed the presence of the fungus. Treatment with itraconazole (ITZ) was initiated but clinical improvement was unremarkable; due to the fact that the patient was taking sodium valproate for seizure control, drug interactions were suspected and confirmed by absence of ITZ plasma levels. The latter medication was changed to clonazepam and after several weeks, clinical improvement began to be noticed and was accompanied by diminishing P. brasiliensis antigen and antibody titers. In the PCM endemic areas, CNS involvement should be considered more often and the efficacy of itraconazole therapy should also be taken into consideration.

Effects of amphotericin B and three azole derivatives on the lipids of yeast cells of Paracoccidioides brasiliensis

Yeast cells of five different strains of Paracoccidioides brasiliensis were obtained for partial analysis of lipid composition, and sterol content was determined quantitatively and qualitatively. The determinations were conducted with cells cultured in the presence and absence of amphotericin B and azole derivatives at levels below the MIC.

The role of HLA antigens in the development of paracoccidioidomycosis

BACKGROUND

Paracoccidioidomycosis is a systemic granulomatous disease that involves primarily the lungs and may disseminate to other organs and systems. It is caused by Paracoccidioides brasiliensis, a fungus that exhibits reversible thermal dimorphism and whose natural habitat is presently unknown. There are two main clinical forms: the acute (subacute) juvenile form and the chronic adult form. The former runs a more rapid course and is more severe than the latter. This mycosis is found throughout Latin America. Brazil accounts for 80% of reported cases. Presumably P. brasiliensis thrives in humid and hot places, especially near forests or farms. The infection is endemic in certain areas, especially in Brazil, Colombia and Venezuela, where nearly 100% of the population show cutaneous paracoccidioidina positive skin tests, indicating previous contact with the fungus, although a small percentage show clinical manifestations of the disease.

METHODS

We compared the expression of HLA class I antigens in a healthy group (control) and in a group of patients with paracoccidioidomycosis (chronic adult form) using the Terasaki lymphocytotoxicity test modified by Amos for HLA antigen analysis.

AIMS

To discover indications of whether or not individual susceptibility to P. brasiliensis might depend on some specific immunological defect.

RESULTS

There is no evidence of association between a specific HLA antigen and paracoccidioidomycosis in the subjects studied. Further investigations are recommended.

Molecular cloning and characterization of a glucan synthase gene from the human pathogenic fungus Paracoccidioides brasiliensis

1,3-beta-D-glucan is a fungal cell wall polymer synthesized by the multi-subunit enzyme 1,3-beta-D-glucan synthase. A subunit of this integral membrane protein was first described as the product of the FKS1 gene from Saccharomyces cerevisiae using echinocandin mutants. Other FKS1 genes were also reported for Candida albicans, Aspergillus nidulans and Cryptococcus neoformans. Here, we report the nucleotide sequence of the first homologous FKS gene cloned from the pathogenic fungus Paracoccidioides brasiliensis. An open reading frame of 5942 bp was identified in the complete sequence, interrupted by two putative introns, the first close to the 5' end and the second close to the 3' end of the gene. A promoter region is also described containing consensus sequences such as canonical TATA and CAAT boxes and, possibly, multiple sites for glucose regulation by creA protein. The deduced sequence of 1926 amino acid show more than 85% similarity to FksAp from A. nidulans, and 71% to Fks1p and Fks2p from S. cerevisiae. Computational analysis of P. brasiliensis Fks1p suggests a similar structure to transmembrane proteins, such as FksAp, with the presence of two domains composed by hydrophobic helices that limit the putative highly hydrophilic catalytic domain within the cytoplasm.

Fibrotic sequelae in pulmonary paracoccidioidomycosis: histopathological aspects in BALB/c mice infected with viable and non-viable paracoccidioides brasiliensis propagules

Patients with paracoccidioidomycosis often present pulmonary fibrosis and exhibit important respiratory limitations. Based on an already established animal model, the contribution of viable and non-viable P. brasiliensis propagules to the development of fibrosis was investigated. BALB/c male mice, 4-6 weeks old were inoculated intranasally either with 4x10(6) viable conidia (Group I), or 6. 5x10(6) fragmented yeast cells (Group II). Control animals received PBS. Six mice per period were sacrificed at 24, 48, 72h (initial) and 1, 2, 4, 8, 12 and 16 weeks post-challenge (late). Paraffin embedded lungs were sectioned and stained with H&E, trichromic (Masson), reticulin and Grocot&tacute;s. During the initial period PMNs influx was important in both groups and acute inflammation involving 34% to 45% of the lungs was noticed. Later on, mononuclear cells predominated. In group I, the inflammation progressed and granulomas were formed and by the 12th week they fussed and became loose. Thick collagen I fibers were observed in 66.6% and 83.3% of the animals at 8 and 12 weeks, respectively. Collagen III, thick fibers became apparent in some animals at 4 weeks and by 12 weeks, 83% of them exhibited alterations in the organization and thickness of these elements. In group II mice, this pattern was different with stepwise decrease in the number of inflammatory foci and lack of granulomas. Although initially most animals in this group had minor alterations in thin collagen I fibers, they disappeared by the 4th week. Results indicate that tissue response to fragmented yeast cells was transitory while viable conidia evoked a progressive inflammatory reaction leading to granuloma formation and to excess production and/or disarrangement of collagens I and III; the latter led to fibrosis.

Anti-idiotypic antibodies in patients with different clinical forms of paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Latin America. Patients with PCM show a wide spectrum of clinical and pathological manifestations depending on both host and pathogen factors. Two clinical forms of the disease are recognized: the acute or juvenile form and the chronic or adult form. The major antigenic component of the parasite is a glycoprotein of 43 kDa (gp43). All patient sera present antibodies against gp43 (anti-gp43) and, as demonstrated before by our group, spontaneous anti-idiotypic (anti-Id) antibodies (Ab2) can be detected in patient sera with high titers of anti-gp43. Since it has been postulated that anti-Id antibodies may have a modulating function, we decided to purify and characterize anti-Id antibodies in this system. The possible correlation of Ab2 titers with different clinical forms of disease was also verified. Results showed that purified human anti-Id antibodies (human Ab2) recognized specifically the idiotype of some murine monoclonal anti-gp43 (17c and 3e) but not others (40.d7, 27a, and 8a). Spontaneous anti-Id antibodies were found in all clinical forms of disease. The majority of patients (88%, n = 8) with the acute form of PCM had high titers of Ab2. However, among patients with the multifocal chronic form of the disease, only 29% (n = 14) had high titers of Ab2; 70% (n = 10) of patients with the unifocal chronic form had low titers of Ab2. A correlation between Ab2 titers and anti-gp43 titers was observed before and during antimycotic treatment. Our results suggest that titers of anti-Id antibodies correlate with the severity of PCM in humans.

Depletion of CD8(+) T cells in vivo impairs host defense of mice resistant and susceptible to pulmonary paracoccidioidomycosis

Using a pulmonary model of infection, we demonstrated previously that A/Sn and B10.A mice are, respectively, resistant and susceptible to Paracoccidioides brasiliensis infection. Employing the same experimental model, we examined herein the role of CD8(+) T cells in the course of paracoccidioidomycosis. Treatment with anti-CD8 monoclonal antibodies caused a selective depletion of pulmonary and splenic CD8(+) T cells in both mouse strains. The number of pulmonary CD4(+) T cells and immunoglobulin-positive cells was independent of the number of CD8(+) T cells. In susceptible mice, the loss of CD8(+) T cells by in vivo treatment with anti-CD8 monoclonal antibodies impaired the clearance of yeasts from the lungs and increased the fungal dissemination to the liver and spleen. The same treatment in resistant mice increased fungal dissemination to extrapulmonary tissues but did not alter the pulmonary fungal load. Furthermore, CD8(+) T-cell depletion did not modify delayed-type hypersensitivity reactions of A/Sn mice but increased these reactions in B10.A mice. The production of P. brasiliensis-specific antibodies by resistant and susceptible mice depleted of CD8(+) T cells was similar to that of mice given control antibody. Histopathologically, depletion of CD8(+) T cells did not disorganize the focal granulomatous lesions developed by both mouse strains. These results indicate that CD8(+) T cells are necessary for optimal clearance of the fungus from tissues of mice infected with P. brasiliensis and demonstrate more prominent protective activity by those cells in the immune responses mounted by susceptible animals.

PCR with Paracoccidioides brasiliensis specific primers: potential use in ecological studies

The precise microenvironment of Paracoccidioides brasiliensis has not yet been discovered perhaps because the methods used are not sensitive enough. We applied to this purpose the polymerase chain reaction (PCR) using three sets of specific primers corresponding to two P. brasiliensis genes. This fungus as well as several other fungi, were grown and their DNA obtained by mechanical disruption and a phenol chloroform isoamylalcohol-based purification method. The DNA served for a PCR reaction that employed specific primers from two P. brasiliensis genes that codify for antigenic proteins, namely, the 27 kDa and the 43 kDa. The lowest detection range for the 27 kDa gene was 3 pg. The amplification for both genes was positive only with DNA from P. brasiliensis; additionally, the mRNA for the 27 kDa gene was present only in P. brasiliensis, as indicated by the Northern analysis. The standardization of PCR technology permitted the amplification of P. brasiliensis DNA in artificially contaminated soils and in tissues of armadillos naturally infected with the fungus. These results indicate that PCR technology could play an important role in the search for P. brasiliensis' habitat and could also be used in other ecological studies.

Paracoccidioides brasilienses isolates obtained from patients with acute and chronic disease exhibit morphological differences after animal passage

The basis for virulence in Paracoccidioides brasiliensis is not completely understood. There is a consensus that the sequential in vitro subcultivation of P. brasiliensis leads to loss of its pathogenicity, which can be reverted by reisolation from animal passage. Attention to morphological and biochemical properties that are regained or demonstrated after animal passage may provide new insights into factors related to the pathogenicity and virulence of P. brasiliensis. We evaluated morphological characters: the percentage of budding cells, number of buds by cell and the diameter of 100 mother cells of yeast-like cells of 30 P. brasiliensis isolates, before and after animal passage. The isolates were obtained from patients with different clinical forms of paracoccidioidomycosis (PCM): acute form (group A, n=15) and chronic form (group C, n=15). The measurement of the yeast cell sizes was carried out with the aid of an Olympus CBB microscope coupled with a micrometer disc. We measured the major transverse and longitudinal axes of 100 viable cells of each preparation. The percentage of budding cells as also the number of buds by cell was not influenced by animal passage, regardless of the source of the strain (acute or chronic groups). The size values of P. brasiliensis isolates from groups A and C, measured before the animal passage exhibited the same behavior. After animal passage, there was a statistically significant difference between the cell sizes of P. brasiliensis isolates recovered from testicles inoculated with strains from groups A and C. The maximum diameter of mother cells from group A isolates exhibited a size of 42.1 microm in contrast with 32.9 microm exhibited by mother cells from group C (p<0.05). The diameter of 1500 mother cells from group A isolates exhibited a medium size of 16.0 microm (SD +/- 4.0), a value significantly higher than the 14.1 microm (SD = +/- 3.3) exhibited by 1500 mother cells from group C isolates (p<0.05). Our results reinforce the polymorphism exhibited by P. brasiliensis in biological material and the need for further investigations to elucidate the role of morphological parameters of the fungus in the natural history of the disease.

Comparison between human and armadillo Paracoccidioides brasiliensis isolates by random amplified polymorphic DNA analysis

Sixty-three Paracoccidioides brasiliensis isolates obtained from three nine-banded armadillos (Dasypus novemcinctus), one Amazonian armadillo's and 19 clinical isolates were compared by random amplified polymorphic DNA analysis with the primer OPG-19. The isolates were divided into three major clusters, I, II and III. Coincidences between human and armadillo isolates were observed in clusters I and II. Cluster III consisted only of armadillos' isolates. The results suggested that (I) humans may acquire P. brasiliensis infection by contact with armadillo's environment, (II) there may be P. brasiliensis genotypes peculiar to the animal, and (III) individual armadillos may be infected with P. brasiliensis cells with different genotypes.

Histoplasmosis and Paracoccidioidomycosis in northwestern Argentina III. Epidemiological survey in Vipos, La Toma, and Choromoro - Trancas, Tucumán, Argentina

The present work was undertaken to obtain epidemiological data on the extent and distribution of Histoplasma capsulatum var. capsulatum and Paracoccidiodes brasiliensis diseases in the Vipos, La Toma and Choromoro areas. Skin test surveys with histoplasmin and paracoccidioidin were carried out in the permanent human population of those localities. Mycological sputum studies and serological tests were performed to skin test reactors to determine if there were signs or symptoms of active mycotic disease. La Toma and Choromoro are highly prevalent areas of histoplasmosis (>30% the histoplasmin positive individuals) whereas Vipos can be relatively considered a highly prevalent area (between 20-30% the histoplasmin reactors) according to the normally accepted range used to define an endemic disease [2]. Early Histoplasma capsulatum infection (<10 years old) is reported for Vipos and Choromoro. La Toma has the highest rate of previous exposure to P. brasiliensis detected in the studied area (10.2%). Vipos residents are not infected with P. brasiliensis.

Pattern of immune response to GP43 from Paracoccidioides brasiliensis in susceptible and resistant mice is influenced by antigen-presenting cells

Paracoccidioidomycosis (PCM), endemic in Latin America, is a progressive systemic mycosis caused by Paracoccidioides brasiliensis. The infection can evolve to different clinical forms that are associated with various degrees of suppressed cell-mediated immunity. In the murine model, A/Sn and B10.A isogenic strains of mice are known to be resistant and susceptible, respectively, to this fungal infection. Assuming that the effector immune response is a consequence of the preferential activation of either Th1 or Th2 subsets, in the present work we evaluated the importance of two antigen-presenting cells (APCs), macrophages and B cells, in the development of the immune response to P. brasiliensis. In resistant mice, purified gp43, the main antigenic component of P. brasiliensis, seems to have been preferentially presented by macrophages and stimulated Th1 lymphokine production. On the other hand, in susceptible animals gp43 was distinguishably presented by B cells, which led to stronger activation of Th2 subsets. Moreover, T cells from resistant mice responded as those from susceptible animals when stimulated by gp43 presented by APCs from susceptible mice and vice versa, indicating that there are no significant differences in the T cell repertoires from A/Sn and B10.A mice. When T cells from F1 (A/Sn x B10.A) mice were stimulated by gp43 presented by APCs from A/Sn or B10.A, impaired behavior of B10.A macrophages in activating Th1 cells and a B10.A B cell tendency to stimulate T cells that secrete higher levels of IL-10 were observed. Taken together, our results suggest that APCs may be implicated in the outcome of P. brasiliensis infection.

Use of the 27-kilodalton recombinant protein from Paracoccidioides brasiliensis in serodiagnosis of paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is one of the most important endemic mycoses in Latin America; it is usually diagnosed by observation and/or isolation of the etiologic agent, Paracoccidioides brasiliensis, as well as by a variety of immunological methods. Although the latter are effective, two circumstances, cross-reactions with other mycotic agents and antigen preparation that is marked by extreme variability among lots, hinder proper standardization of the procedures. To circumvent this lack of reproducibility, molecular biology tools were used to produce a recombinant 27-kDa-molecular-mass antigen from this fungus; a sizable quantity of this antigen was obtained through fermentation of Escherichia coli DH5alpha, which is capable of expressing the fungal protein. The latter was purified by the Prep-Cell System (Bio-Rad); the recovery rate of the pure protein was approximately 6%. A battery of 160 human serum samples, consisting of 64 specimens taken at the time of diagnosis from patients with PCM representing the various clinical forms plus 15 serum specimens each from patients with histoplasmosis and aspergillosis, 10 each from patients with cryptococcosis and tuberculosis, 6 from patients with coccidioidomycosis, and 40 from healthy subjects, were all tested by an indirect enzyme-linked immunosorbent assay with the purified 27-kDa recombinant protein. The latter was used at a concentration of 1.0 microgram/well; there were three serum dilutions (1:1,000, 1:2,000, and 1:4,000). The experiment was repeated at least twice. The average sensitivity for both experiments was 73.4%; in comparison with the healthy subjects, the specificity for PCM patients was 87.5% while for patients with other mycoses, it was 58.7%. Important cross-reactions with sera from patients with aspergillosis and histoplasmosis were detected. The positive predictive value of the test was 90.4%. These results indicate that it is possible to employ recombinant antigenic proteins for the immunologic diagnosis of PCM and, by so doing, achieve high coverage rates. Furthermore, antigen reproducibility can now be ensured, thus facilitating inter- and intralaboratory standardization.