Immunocytochemical localization of cytokines and inducible nitric oxide synthase (iNOS) in oral mucosa and lymph nodes of patients with paracoccidioidomycosis

Contribution to the study of inflammasome and programmed cell death in paracoccidioidomycosis oral lesions

BACKGROUND

Paracoccidioidomycosis is the most prevalent systemic mycosis in Latin America, with a high incidence in Brazil, Colombia and Venezuela, and constitutes a serious public health problem, a frequent cause of morbidity and disability for work. Some mechanisms of cell death are described as important tools in infectious processes. When apoptosis is blocked, RIPK (Receptor-interacting protein kinase) 3 dependent, a caspase-independent form of cell death, can limit the replication and spread of pathogens. Some molecules that mediate necroptosis include RIPK3 and have been extensively studied due to their signalling mechanism and pathological function. RIPK3 activates NLRP1 and NLRP3-mediated inflammasome formation. Caspase-1 has an important role in processing the cytokines ILβ and IL18 to their active form. Such molecules are part of the inflammasome characterization, whose caspase-1-dependent activation promotes the death of pyroptotic cells and the secretion of proinflammatory cytokines. Knowledge about the mechanisms of pathogen-mediated cell death can be useful for understanding of the pathogenesis of infections and inflammatory conditions.

OBJECTIVE

The objective of this work was to identify the mechanisms of programmed cell death and inflammasome components in human oral mucosal lesions of paracoccidioidomycosis through immunohistochemical methods and identification of RIPK-3, IL1β, IL18, NLRP-1 and caspase-1. Thirty specimens were included, and a histopathological analysis of the lesions was performed using haematoxylin-eosin staining.

RESULTS

Our results on in situ expression of inflammasome elements and programmed cell death showed increased expression of IL-1β, NLRP-1, caspase-1 and RIPK-3. We suggest that inflammasome complex participate in the immunopathogenesis in paracoccidioidomycosis oral lesions in an interplay with RIPK3.

Updates in Paracoccidioides Biology and Genetic Advances in Fungus Manipulation

The dimorphic fungi of the Paracoccidioides genus are the causative agents of paracoccidioidomycosis (PCM). This disease is endemic in Latin America and primarily affects workers in rural areas. PCM is considered a neglected disease, despite being a disabling disease that has a notable impact on the public health system. Paracoccidioides spp. are thermally dimorphic fungi that present infective mycelia at 25 °C and differentiate into pathogenic yeast forms at 37 °C. This transition involves a series of morphological, structural, and metabolic changes which are essential for their survival inside hosts. As a pathogen, the fungus is subjected to several varieties of stress conditions, including the host immune response, which involves the production of reactive nitrogen and oxygen species, thermal stress due to temperature changes during the transition, pH alterations within phagolysosomes, and hypoxia inside granulomas. Over the years, studies focusing on understanding the establishment and development of PCM have been conducted with several limitations due to the low effectiveness of strategies for the genetic manipulation of Paracoccidioides spp. This review describes the most relevant biological features of Paracoccidioides spp., including aspects of the phylogeny, ecology, stress response, infection, and evasion mechanisms of the fungus. We also discuss the genetic aspects and difficulties of fungal manipulation, and, finally, describe the advances in molecular biology that may be employed in molecular research on this fungus in the future.

Immunohistochemical localization of TNF-α and IL-4 in granulomas of immunocompetent and immunosuppressed New Zealand white rabbits infected with Encephalitozoon cuniculi

Encephalitozoon cuniculi is a fungi-related, obligate, zoonotic, spore-forming intracellular eukaryotic microorganism. This emerging pathogen causes granulomas to form in the brain and kidneys of infected individuals. The objective of the current study was to detect the distribution of TNF-α- and IL-4-positive cells using immunohistochemistry within these granulomas in both infected immunocompetent (group A) and immunosuppressed (group B) New Zealand white rabbits. In the brain, labeled TNF-α immune cells were mainly located in the granuloma peripheries in group B. Granulomas examined in the kidneys of groups A and B were TNF-α positive, but were significantly different (p < 0.001) when compared with the brain. IL-4-producing immune cells in the brain and kidneys were disseminated within granulomas in groups A and B; however, no significant difference (p > 0.05), was observed. IL-4 positive cells were more numerous in brain sections of group B and differed significantly (p < 0.05) when compared with kidneys. Granulomas were not observed in control animals (groups C and D). In conclusion, we identified TNF-α positive cells in both the brain and kidneys of immunocompetent and immunosuppressed animals; IL-4 positive cells were numerous in the brains of immunosuppressed rabbits; however, in terms of percentage were numerous in the brains of immunocompetent rabbits. Immunosuppression appeared to stimulate a change in the cellular phenotype of Th1- to Th2-like granulomas in the brain and kidneys via an unknown mechanism. Expression of pro- and pre-inflammatory cytokines in microsporidian granulomas suggests a mechanism by which E. cuniculi evades the immune response, causing more severe disease. These results increase our understanding of TNF-α and IL-4-positive cells within the E. cuniculi granuloma microenvironment.

Therapeutic effect of DNA vaccine encoding the 60-kDa-heat shock protein from Paracoccidoides brasiliensis on experimental paracoccidioidomycosis in mice

Paracoccidioidomycosis (PCM) is a systemic mycosis autochthonous to Latin America and endemic to Brazil, which has the majority of the PCM cases. PCM is acquired through the inhalation of propagules of fungi from genus Paracoccidioides spp. and mainly affects the lungs. We have previously shown that P. brasiliensis-infected mice treated with single-dose of recombinant 60-kDa-heat shock protein from P. brasiliensis (rPbHsp60) had a worsening infection in comparison to animals only infected. In this study, we investigate whether the treatment of infected mice with PB_HSP60 gene cloned into a plasmid (pVAX1-PB_HSP60) would result in efficient immune response and better control of the disease. The harmful impact of single-dose therapy with protein was not seen with plasmid preparations. Most importantly, three doses of pVAX1-PB_HSP60 and protein induced a beneficial effect in experimental PCM with a reduction in fungal load and lung injury when compared with infected mice treated with pVAX1 or PBS. The increase of the cytokines IFN-γ, TNF, and IL-17 and the decrease of IL-10 observed after treatment with three doses of pVAX1-PB_HSP60 appears to be responsible for the control of infection. These results open perspectives of the therapeutic use of Hsp60 in PCM.

Effect of ArtinM on Human Blood Cells During Infection With Paracoccidioides brasiliensis

Infections caused by fungi are prominent in our environment and can be potentially fatal. paracoccidioidomycosis (PCM), caused by fungi of the Paracoccidioides genus, is the most frequent systemic mycosis in Brazil and the main cause of death among immunocompetent individuals. The antifungal therapy for PCM is usually effective but side effects and relapses are often reported. The latter could be avoided with alternative or complementary therapies aimed at boosting the immune response to combat this pathogen. Recent reports have pointed at the importance of an effective cellular immune response, with the participation of Th1 cells, in the resistance to and control of Paracoccidioides infection. The ArtinM lectin, extracted from jackfruit (Artocarpus heterophyllus) seeds, exhibits immunomodulatory activity against several intracellular pathogens, including Paracoccidioides brasiliensis, by promoting the development of a Th1 immune response. The aim of this work was to characterize the effect of ArtinM on peripheral blood cells of patients with PCM and on those of control individuals infected with fungal yeasts cells in vitro. Our results demonstrate that ArtinM activates human neutrophils in vitro, leading to an increase in cytokine production and CD54 expression. ArtinM activated P. brasiliensis-infected neutrophils from both healthy individuals and patients with PCM. This activation was not dependent on the dectin-1 receptor, because pre-incubation with laminarin, a dectin-1 receptor blocker, did not reverse the activated state of the cells. ArtinM also stimulated human peripheral blood mononuclear cells to secrete pro-inflammatory Th1-related cytokines, which are protective against Paracoccidioides infection. These data support the immunostimulatory action of ArtinM and encourage new studies using the lectin for the immunotherapy of PCM.

M2 macrophages and inflammatory cells in oral lesions of chronic paracoccidioidomycosis

BACKGROUND

Paracoccidioidomycosis (PCM) is a systemic fungal infection caused by Paracoccidioides brasiliensis (Pb) and associated with deficient cellular immune response, which is modulated by inflammatory cells, mainly macrophages, and cytokines. Recently, the comprehension of the macrophage polarization mediated by Th1 and Th2 cytokines has contributed to elucidate the immune response that takes part in some diseases. Thus, the aim of this study was to assess the presence of Th1- and Th2-immune response and also Pb counting in oral lesions of chronic PCM.

METHODS

Forty-eight cases of chronic PCM oral lesions were included. All cases were classified as loose or dense granulomas. S100 protein, IL-1β, IL-6, TNF-α, CD163 and CD68 immunoexpressions, and Pb localization were evaluated. The fungi present in the tissue were quantified by anti-Pb antibody.

RESULTS

Most patients were white men with mean age of 47 years old and showed higher incidence of multiple lesions. Loose granulomas were predominant and exhibited a great amount of M2 macrophages, which were visualized with anti-CD163 antibody. The expression for CD163 and CD68 was similar (P = 0.05), highlighting the predominance of M2 macrophages in PCM. IL-1β, IL-6, and TNF-α immunoexpression did not significantly change with CD163, CD68, and S100 protein. The number of fungi was significantly higher in cases with intense IL-1β immunoexpression (P = 0.003).

CONCLUSIONS

M2-activated macrophages were the majority among inflammatory cells in chronic PCM, characterizing the action of a Th2-immune response. Nevertheless, Th1 cytokines were also found; mainly IL-1β, which was associated with fungi counting in oral lesions.

Human neutrophils produce IL-12, IL-10, PGE2 and LTB4 in response to Paracoccidioides brasiliensis. Involvement of TLR2, mannose receptor and dectin-1

The functions of phagocytic cells against pathogens are initiated by the interaction between membrane receptors and molecular structures which compose the cell wall of these microorganisms. Thus our study aimed to identify the neutrophil receptors involved in the recognition of different strains of Paracoccidioides brasiliensis and the consequent modulation of immune response through the production of cytokines and inflammatory mediators. Neutrophils did not produce TNF-alfa in response to both strains. However, these cells produce IL-12, mainly in response to Pb 265, with participation of TLR2 and dectin-1. These cells also produce L-10, whose levels were higher for Pb 18 with involvement of TLR2 and MR and only TLR2 for Pb 265. The production of PGE2 and LTB4 was detected similarly for the two strains. For PGE2, MR and dectin-1 were involved, while in relation to LTB4, none of them. In summary, we demonstrated that neutrophils have a dynamic role during host immune response to P. brasiliensis, since in addition to their role as effector cells of innate immunity; they have the capacity to modulate innate and adaptative immune response against this fungus by producing cytokines and lipidic mediators. This modulation may be toward a pró- or anti-inflammatory pattern in a dependence of P. brasiliensis strains and PRR involved in fungus recognition by these cells.

Regulatory T cells in cutaneous lesions of patients with Paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by the dimorphic fungus Paracoccidioides brasiliensis, with high incidence in Brazil and very significant in Latin America. The disease is clinically classified as acute, subacute or chronic where the primary lesion initiates in the lungs and can spread to other organs such as the skin and mucous membranes. The lesions are characterized by granulomatous formation, organized according to the type of pattern of host immune response. We demonstrated and quantified by immunohistochemistry the expression of Foxp3, CD25, TGF-beta and IL-10 in thirty cutaneous lesions with different presentation of granulomatous response. Cells expressing Foxp3 and CD25 were increased in lesions with compact granulomas. The expression of TGF-beta and IL-10 was similar in all PCM lesions. As previous studies, our data suggest the correlation of Treg cells with the chronicity of the disease and the participation in suppressing mechanism as a possible source of IL-10. TGF-β and IL-10, two important suppressor cytokines, are expressed in great amounts in the lesions but our results do not allow correlating with the differences in the granulomatous response.

Interrelationship of clinical, histomorphometric and immunohistochemical features of oral lesions in chronic paracoccidioidomycosis

BACKGROUND

This study aimed to analyze the oral lesions of chronic paracoccidioidomycosis concerning their histomorphometric, immunohistochemical, and clinical features in a standardized sample.

METHODS

Fifty biopsy specimens of oral lesions of chronic paracoccidioidomycosis were submitted to hematoxylin and eosin (H&E), Grocott-Gomori and immunohistochemical staining. Data regarding disease duration and size and number of oral lesions, as well as erythrocytes, leukocytes, lymphocytes, hematocrit, hemoglobin, and erythrocyte sedimentation rate, were collected from medical charts. Granuloma density and number and diameter of buds and fungal cells, and IL-2, TNF-alpha and IFN-gamma expression, as well as clinical and hematological features, were quantified and correlated.

RESULTS

Bud diameter was significantly greater in intermediate density granulomas compared to higher density granulomas. The other variables (number of buds, number and diameter of fungi, expression of IL-2, TNF-alpha and IFN-gamma, and clinical and hematological features) did not significantly change with the density of granulomas. There was a positive correlation between bud number and fungal cell number (r = 0.834), bud diameter and fungal cell diameter (r = 0.496), erythrocytes and number of fungi (r = 0.420), erythrocytes and bud number (r = 0.408), and leukocytes and bud number (r = 0.396). Negative correlation occurred between number and diameter of fungi (r = -0.419), bud diameter and granuloma density (r = -0.367), TNF-alpha expression and number of fungi (r = -0.372), and TNF-alpha expression and bud number (r = -0.300).

CONCLUSION

The histological, immunological, and clinical features of oral lesions evaluated did not differ significantly between patients in our sample of chronic paracoccidioidomycosis. TNF-alpha levels were inversely correlated with intensity of infection.

Comparative study of the in situ immune response in oral and nasal mucosal leishmaniasis

Mucosal Leishmaniasis (ML) may occur in both nasal and oral mucosa. However, despite the impressive tissue destruction, little is known about the oral involvement. To compare some changes underlying inflammation in oral and nasal ML, we performed immunohistochemistry on mucosal tissue of 20 patients with ML (nasal [n = 12]; oral [n = 8] lesions) and 20 healthy donors using antibodies that recognize inflammatory markers (CD3, CD4, CD8, CD22, CD68, neutrophil elastase, CD1a, CLA, Ki67, Bcl-2, NOS2, CD62E, Fas and FasL). A significantly larger number of cells, mainly T cells and macrophages, were observed in lesions than in healthy tissue. In addition, high nitric oxide synthase 2 (NOS2) expression was associated with a reduced detection of parasites, highlighting the importance of NOS2 for parasite elimination. Oral lesions had higher numbers of neutrophils, parasites, proliferating cells and NOS2 than nasal lesions. These findings, together with the shorter duration of oral lesions and more intense symptoms, suggest a more recent inflammatory process. It could be explained by lesion-induced oral cavity changes that lead to eating difficulties and social stigma. In addition, the frequent poor tooth conservation and gingival inflammation tend to amplify tissue destruction and symptoms and may impair and confuse the correct diagnosis, thus delaying the onset of specific treatment.

Immunology of paracoccidioidomycosis

Paracoccidioidomycosis is the most prevalent systemic mycosis in Latin America, among immunecompetent patients. It's caused by the dimorphic fungus Paracoccidioiddes brasiliensis. Investigations regarding its immunopathogenesis are very important in the understanding of aspects related to natural history, as the protective immunity, and the relationship between host and parasite; also favoring the knowledge about clinical patterns and the elaboration of therapeutic strategies. The disease clinical polymorphism depends, at least, of the immune response profile according to the tissue and blood released citokynes, resulting in tissue damage.

Recipient of kidney from donor with asymptomatic infection by Paracoccidioides brasiliensis

The increase in solid organ transplantations may soon create a rise in the occurrence of endemic fungal diseases, such as paracoccidioidomycosis, due to the lack of rigorous screening of donors from endemic areas. Here we present the first case of an immunocompetent and asymptomatic kidney donor who had Paracoccidioides brasiliensis infected-adrenal tissue but no glandular dysfunction.

Nitric oxide participation in granulomatous response induced by Paracoccidioides brasiliensis infection in mice

The role of nitric oxide (NO) in granulomas of Paracoccidioides brasiliensis-infected inducible NO synthase-deficient C57BL/6 mice (iNOS KO) and their wild-type counterparts and its association with osteopontin (OPN) and matrix metalloproteinases (MMPs) was studied. At 15 days after infection (DAI), iNOS KO mice showed compact and necrotic granulomas with OPN+ macrophages and multinucleated giant cells, whereas wild-type mice developed loose granulomas with many fungi and OPN+ cells distributed throughout the tissue. In addition, high OPN levels and fungal load were observed in iNOS KO mice. Both experimental groups had MMP-9 activity. At 120 DAI, iNOS KO had smaller granulomas with OPN+ cells, lower OPN levels, lower fungal load and decreased MMP-9 activity compared with wild-type mice. These findings suggest that NO has an important role in granuloma modulation, by controlling OPN and MMP production, as well as by inducing loose granulomas formation and fungal dissemination, resulting, at later phases, in progression of paracoccidioidomycosis.

Serum interleukin-18 and soluble tumour necrosis factor receptor 2 are associated with disease severity in patients with paracoccidioidomycosis

Interleukin (IL)-18 is a proinflammatory cytokine of the IL-1 superfamily that exhibits broad functional effects in innate and acquired immune responses and which has been found in high levels in several chronic inflammatory and autoimmune diseases. Over-expression of IL-18 may promote early resolution of infection or could promote a detrimental exaggerated immune response. The aim of this study was to determine serum levels of IL-18 and other inflammatory mediators [IL-12, soluble intercellular adhesion molecule 1 (sICAM-1), soluble tumour necrosis factor receptor 1 (TNF-RI), sTNF-RII, CXC chemokine ligand 9 (CXCL9), CXCL10] at baseline and after anti-fungal therapy in serum from patients with juvenile (JF) and adult (AF) forms of paracoccidioidomycosis (PCM), as well as in healthy controls (C), and to assess their possible relationships to the severity of disease. IL-18 and sTNF-RII levels in patients with the JF of PCM were significantly higher than those in the AF and controls. In relation to sICAM-1, no difference was observed between JF and AF patients but both presented higher levels than controls. sTNF-RI levels were higher in patients with PCM than in controls, and significantly higher concentrations were detected in AF patients compared to JF patients. Moreover, IL-12 and chemokines CXCL9 and CXCL10 were also higher in patients than in controls. In JF patients IL-18 levels correlated significantly with sICAM-1 (r=0 x 62, P<0 x 0001), sTNF-RI (r=0 x 63, P<0 x 0001), sTNF-RII (r=0 x 51, P=0 x 02), as well as with clinical severity. The results suggest the value of serum IL-18 and sTNF-Rs levels as a parameter of PCM severity and may support a possible role for them in the pathogenesis of the disease.

Paracoccidioidomicose em hemisfério cerebral e tronco encefálico: relato de caso

Relata-se sobre um homem de 36 anos com passagem quatro anos antes pela selva amazônica. Admitido após seis meses do aparecimento progressivo de tetraparesia, ataxia de marcha, disfagia, disartria, dispnéia e soluço. A ressonância magnética revelou lesão parietoccipital à direita e no bulbo, sendo esta última maior. Investigações para tuberculose e síndrome da imunodeficiência adquirida tiveram resultados negativos. Foi submetido a microcirurgia da lesão do bulbo. O estudo anatomopatológico revelou paracoccidioidomicose. Recebeu tratamento com anfotericina B até 2100 mg, e sulfametoxazol-trimetoprim por três meses, e fisioterapia. Voltou às atividades após seis meses do término do tratamento. Comenta-se sobre a participação do sistema imunológico e das citocinas (interleucinas).

Cytokines released from blood monocytes and expressed in mucocutaneous lesions of patients with paracoccidioidomycosis evaluated before and during trimethoprim-sulfamethoxazole treatment

BACKGROUND

Mucocutaneous lesions in paracoccidioidomycosis are granulomatous and result from tissue responses to Paracoccidioides brasiliensis, the aetiological agent.

OBJECTIVES AND METHODS

In this study we investigate the expression of tumour necrosis factor (TNF)-alpha, interleukin (IL)-10 and transforming growth factor (TGF)-beta1 by immunohistochemistry in skin and mucosa lesions from patients with the chronic form of paracoccidioidomycosis, evaluated before and at day 20 of trimethoprim-sulfamethoxazole treatment. Cytokine production by peripheral blood monocytes was also studied by enzyme immunoassay.

RESULTS

Intense immunostaining for TNF-alpha was detected in mononuclear cells that infiltrated granulomas in all skin and mucosa lesions before treatment simultaneously with low IL-10 granular deposits in these cells. At day 20 of treatment, there was reduced TNF-alpha and IL-10 deposition. Immunoreactive TGF-beta1 was observed diffusely in the dermis and generally in the cytoplasm of macrophages and giant cells, before treatment, and as increased TGF-beta1 deposits in the fibrosis area at day 20 of treatment. Peripheral blood monocytes from patients with paracoccidioidomycosis, evaluated before treatment, produced high endogenous levels of TNF-alpha, TGF-beta1 and IL-10 in relation to healthy controls. Lipopolysaccharide-stimulated monocytes from patients secreted lower levels of TNF-alpha in both periods of evaluation while no impairment in capacity of IL-10 and TGF-beta production was observed.

CONCLUSIONS

Trimethoprim-sulfamethoxazole therapy was effective in decreasing fungal load in the lesions, allowing patient immune response to control the infection leading to the healing of the lesions.

TNF-α activates human monocytes forParacoccidioides brasiliensiskilling by an H2O2-dependent mechanism

Human monocytes activated by recombinant tumor necrosis factor alpha (TNF-alpha) exhibited significant fungicidal activity on the yeast cells of a highly virulent strain of Paracoccidioides brasiliensis. This process was significantly inhibited in the presence of catalase (CAT - a scavenger of H2O2), but not in the presence of superoxide-dismutase (SOD - a scavenger of superoxide anion) or NG-monomethyl-L-arginine (NG-MMLA - a nitric oxide inhibitor). Furthermore, there was a direct association between the intracellular killing of the fungus and the production of H2O2 by activated cells. These results strongly suggest a role for H2O2 in the killing of highly virulent strains of P. brasiliensis by TNF-alpha-activated human monocytes.

Failure of nitric oxide production by macrophages and decrease in CD4+ T cells in oral paracoccidioidomycosis: possible mechanisms that permit local fungal multiplication

Paracoccidioidomycosis is a chronic granulomatous disease that induces a specific inflammatory and immune response. The participation of nitric oxide (NO), a product of the inducible nitric oxide synthase enzyme (iNOS), as an important fungicidal molecule against Paracoccidioides brasiliensis has been demonstrated. In order to further characterize the Oral Paracoccidioidomycosis (OP), we undertook an immunohistochemical study of iNOS+, CD45RO+, CD3+, CD8+, CD20+, CD68+ cells and mast cells. The samples were distributed in groups according to the number of viable fungi per mm². Our results showed weak immunolabeling for iNOS in the multinucleated giant cells (MNGC) and in most of the mononuclear (MN) cells, and the proportion of iNOS+ MN/MNGC cells in the OP were comparable to Control (clinically healthy oral tissues). Additionally, our analysis revealed a similarity in the number of CD4+ cells between the Control and the OP groups with higher numbers of fungi. These findings suggest that a low expression of iNOS and a decrease in the CD4+ T cells in OP may represent possible mechanisms that permit the local fungal multiplication and maintenance of active oral lesions.

The role of interleukin-10 in the differential expression of interleukin-12p70 and its beta2 receptor on patients with active or treated paracoccidioidomycosis and healthy infected subjects

Paracoccidioidomycosis patients present an antigen-specific Th1 immunosuppression. To better understand this phenomenon, we evaluated the interleukin (IL)-12 pathway by measuring IL-12p70 production and CD3+ T cell expression of the IL-12 receptor (IL-12R)beta1/beta2 chains, induced with the main fungus antigen (gp43) and a control antigen, from Candida albicans (CMA). We showed that gp43-induced IL-12p70 production and IL-12Rbeta2 expression were significantly decreased in acute and chronic patients as compared to healthy subjects cured from PCM or healthy infected subjects from endemic areas. Interestingly, the healthy infected subjects had higher gp43-induced IL-12p70 production and beta2 expression than the cured subjects. The addition of a neutralizing anti-IL-10 antibody to the cultures increased IL-12p70 levels and beta2 expression in acute and chronic patients to levels observed in cured subjects. Conversely, addition of the cytokine IL-10 strongly inhibited both parameters in the latter group. In conclusion, we have shown that paracoccidioidomycosis-related Th1 immunosuppression is associated with down-modulation of the IL-12 pathway, that IL-10 may participate in this process, and that patients cured from paracoccidioidomycosis may not fully recover their immune responsiveness.