The cell-mediated immune reaction in the cutaneous lesion of chromoblastomycosis and their correlation with different clinical forms of the disease

Neutrophil extracellular traps (NETs) and Th-2 dominant immune responses in chronic granulomatous chromobalstomycosis

Chromoblastomycosis (CBM), a chronic, granulomatous, suppurative mycosis of the skin and subcutaneous tissue, is caused by several dematiaceous fungi. The formation of granulomas, tissue proliferation, and fibrosis in response to these pathogenic fungi is believed to be intricately linked to host immunity. To understand this complex interaction, we conducted a comprehensive analysis of immune cell infiltrates, neutrophil extracellular traps (NETs) formation, and the fibrosis mechanism in 20 CBM lesion biopsies using immunohistochemical and immunofluorescence staining methods. The results revealed a significant infiltration of mixed inflammatory cells in CBM granulomas, prominently featuring a substantial presence of Th2 cells and M2 macrophages. These cells appeared to contribute to the production of collagen I and III in the late fibrosis mechanism, as well as NETs formation. The abundance of Th2 cytokines may act as a factor promoting the bias of macrophage differentiation toward M2, which hinders efficient fungal clearance while accelerates the proliferation of fibrous tissue. Furthermore, the expression of IL-17 was noted to recruit neutrophils, facilitating subsequent NETs formation within CBM granulomas to impede the spread of sclerotic cells. Understanding of these immune mechanisms holds promise for identifying therapeutic targets for managing chronic granulomatous CBM.

New Immunological Markers in Chromoblastomycosis-The Importance of PD-1 and PD-L1 Molecules in Human Infection

The pathogenesis of chromoblastomycosis (CBM) is associated with Th2 and/or T regulatory immune responses, while resistance is associated with a Th1 response. However, even in the presence of IFN-γ, fungi persist in the lesions, and the reason for this persistence is unknown. To clarify the factors associated with pathogenesis, this study aimed to determine the polarization of the cellular immune response and the densities of cells that express markers of exhaustion in the skin of CBM patients. In the skin of patients with CBM, a moderate inflammatory infiltrate was observed, characterized primarily by the occurrence of histiocytes. Analysis of fungal density allowed us to divide patients into groups that exhibited low and high fungal densities; however, the intensity of the inflammatory response was not related to mycotic loads. Furthermore, patients with CBM exhibited a significant increase in the number of CD4+ and CD8+ cells associated with a high density of IL-10-, IL-17-, and IFN-γ-producing cells, indicating the presence of a chronic and mixed cellular immune response, which was also independent of fungal load. A significant increase in the number of PD-1+ and PD-L1+ cells was observed, which may be associated with the maintenance of the fungus in the skin and the progression of the disease.

Inflammasome and Inflammatory Programmed Cell Death in Chromoblastomycosis

Chromoblastomycosis (CBM) is a chronic, progressive fungal disease of the skin and subcutaneous tissue caused by a group of dematiaceous fungi. Verrucous lesions present parasite-rich granulomas and predominance of a Th2 patterns of cytokines. The inflammasome constitutes a macromolecular protein complex that play a role in the activation of caspase 1 that cleaves pro-IL1β and pro-IL18, essential mediators of inflammation, and also activates pyroptosis. We intended to explore the presence and a possible role of inflammasome elements in cutaneous human lesions in CBM, considering the expression of IL1β, IL18, caspase 1, NLRP1, and also RIPK3, a key downstream component of necroptosis signaling. 35 skin biopsies of cutaneous lesions of verrucous form of CBM and 10 biopsies from normal skin were selected. The diagnosis was based on histological and clinical analysis. An immunohistochemical protocol was performed. The histopathological analysis evidenced epidermis with hyperkeratosis, irregular acanthosis, and micro abscesses. The dermis presented suppurative granulomas and inflammatory infiltrate composed by giant cells, macrophages, epithelioid cells, lymphocytes, and some eosinophils. Positive cells were distributed in the inflammatory infiltrate, with an increased number of cells expressing caspase 1, IL1β and IL18. Cells expressing RIPK3 and NLRP1 were less frequent. The intense presence of caspase 1, IL1β and IL18, allied to NLRP1 expression, suggest that inflammasome and pyroptosis could play a role in the immune response against fungal agents of CBM. Our results, allied to data from literature, could suggest that inflammasome-mediated response and pyroptosis could be a target to be explored to decrease CBM lesions.

Reviewing the Etiologic Agents, Microbe-Host Relationship, Immune Response, Diagnosis, and Treatment in Chromoblastomycosis

Chromoblastomycosis (CBM) is a neglected human disease, caused by different species of pigmented dematiaceous fungi that cause subcutaneous infections. This disease has been considered an occupational disease, occurring among people working in the field of agriculture, particularly in low-income countries. In 1914, the first case of CBM was described in Brazil, and although efforts have been made, few scientific and technological advances have been made in this area. In the field of fungi and host cell relationship, a very reduced number of antigens were characterized, but available data suggest that ectoantigens bind to the cell membrane of host cells and modulate the phagocytic, immunological, and microbicidal responses of immune cells. Furthermore, antigens cleave extracellular proteins in tissues, allowing fungi to spread. On the contrary, if phagocytic cells are able to present antigens in MHC molecules to T lymphocytes in the presence of costimulation and IL-12, a Th1 immune response will develop and a relative control of the disease will be observed. Despite knowledge of the resistance and susceptibility in CBM, up to now, no effective vaccines have been developed. In the field of chemotherapy, most patients are treated with conventional antifungal drugs, such as itraconazole and terbinafine, but these drugs exhibit limitations, considering that not all patients heal cutaneous lesions. Few advances in treatment have been made so far, but one of the most promising ones is based on the use of immunomodulators, such as imiquimod. Data about a standard treatment are missing in the medical literature; part of it is caused by the existence of a diversity of etiologic agents and clinical forms. The present review summarizes the advances made in the field of CBM related to the diversity of pathogenic species, fungi and host cell relationship, antigens, innate and acquired immunity, clinical forms of CBM, chemotherapy, and diagnosis.

Neutrophil-suppressive activity over T-cell proliferation and fungal clearance in a murine model of Fonsecaea pedrosoi infection

Neutrophils are essential to control several fungal infections. These cells are commonly known for their pro-inflammatory activities. However, some studies have demonstrated the anti-inflammatory properties of neutrophils during certain infectious diseases, culminating in the inhibition of T cell proliferation. Chromoblastomycosis (CBM) is a deep and progressive mycosis that affects thousands of people worldwide. Although neutrophil infiltrates are observed in the lesion histopathology, the fungus can overtake the immune system response and destroy the host-infected tissue. The present study demonstrated that neutropenic animals had an increase in the IL-6 production in the spleen and liver, followed by a lower fungal burden in these organs up to 14 days of infection. Neutropenic animals also showed a lower F. pedrosoi-specific antibody production 14-days post infection and higher T-cell proliferation in the in vitro experiments after stimulation with F. pedrosoi-purified proteins. Taken together, our results suggest that the presence of regulatory neutrophils in the mouse model of F. pedrosoi infection could act favoring the spread of the fungus and the chronicity of the infection. These findings shed light on the CBM treatment, which might target neutrophil polarization as a new therapy approach to treat CBM lesions.

Immune Sensing and Potential Immunotherapeutic Approaches to Control Chromoblastomycosis

Chromoblastomycosis (CBM) is a neglected, chronic, and progressive subcutaneous mycosis caused by different species of fungi from the Herpotrichiellaceae family. CBM disease is usually associated with agricultural activities, and its infection is characterized by verrucous, erythematous papules, and atrophic lesions on the upper and lower limbs, leading to social stigma and impacts on patients' welfare. The economic aspect of disease treatment is another relevant issue. There is no specific treatment for CBM, and different anti-fungal drug associations are used to treat the patients. However, the long period of the disease and the high cost of the treatment lead to treatment interruption and, consequently, relapse of the disease. In previous years, great progress had been made in the comprehension of the CBM pathophysiology. In this review, we discuss the differences in the cell wall composition of conidia, hyphae, and muriform cells, with a particular focus on the activation of the host immune response. We also highlight the importance of studies about the host skin immunology in CBM. Finally, we explore different immunotherapeutic studies, highlighting the importance of these approaches for future treatment strategies for CBM.

Early immune response against Fonsecaea pedrosoi requires Dectin-2-mediated Th17 activity, whereas Th1 response, aided by Treg cells, is crucial for fungal clearance in later stage of experimental chromoblastomycosis

Chromoblastomycosis (CBM) is a chronic worldwide subcutaneous mycosis, caused by several dimorphic, pigmented dematiaceous fungi. It is difficult to treat patients with the disease, mainly because of its recalcitrant nature. The correct activation of host immune response is critical to avoid fungal persistence in the tissue and disease chronification. CD4+ T cells are crucial for the development of protective immunity to F. pedrosoi infection. Here, we investigated T helper cell response dynamics during experimental CBM. Following footpad injection with F. pedrosoi hyphae and conidia, T cells were skewed towards a Th17 and Th1 phenotype. The Th17 population was the main Th cell subset found in the infected area during the early stages of experimental murine CBM, followed by Th1 predominance in the later stages, coinciding with the remission phase of the disease in this experimental model. Depletion of CD25+ cells, which leads to a reduction of Treg cells in the draining lymph node, resulted in decline in fungal burden after 14 days of infection. However, fungal cells were not cleared in the later stages of the disease, prolonging CBM clinical features in those animals. IL-17A and IFN-γ neutralization hindered fungal cell elimination in the course of the disease. Similarly, in dectin-2 KO animals, Th17 contraction in the course of experimental CBM was accompanied by fungal burden decrease in the first 14 days of infection, although it did not affect disease resolution. In this study, we gained insight into T helper subsets' dynamics following footpad injections of F. pedrosoi propagules and uncovered their contribution to disease resolution. The Th17 population proved to be important in eliminating fungal cells in the early stages of infection. The Th1 population, in turn, closely assisted by Treg cells, proved to be relevant not only in the elimination of fungal cells at the beginning of infection but also essential for their complete elimination in later stages of the disease in a mouse experimental model of CBM.

Fonsecaea pedrosoi Conidia Induces Activation of Dendritic Cells and Increases CD11c+ Cells in Regional Lymph Nodes During Experimental Chromoblastomycosis

The chromoblastomycosis is a subcutaneous mycosis with a high morbidity rate, Fonsecaea pedrosoi being the largest etiologic agent of this mycosis, usually confined to the skin and subcutaneous tissues. Rarely people get the cure, because the therapies shown to be deficient and few studies report the host-parasite relationship. Dendritic cells (DCs) are specialized in presenting antigens to naïve T lymphocytes inducing primary immune responses. Therefore, we propose to study the migratory capacity of DCs after infection with conidia of F. pedrosoi. The phenotype of DCs was evaluated using cells obtained from footpad and lymph nodes of BALB/c mice after 12, 24 and 72 h of infection. After 24 and 72 h of infection, we found a significant decrease in DCs in footpad and a significant increase in the lymph nodes after 72 h. The expression of surface markers and co-stimulatory molecules were reduced in cells obtained from footpad. To better assess the migratory capacity of DCs migration from footpad, CFSE-stained conidia were injected subcutaneously. We found that after 12 and 72 h, CD11c⁺ cells were increased in regional lymph nodes, leading us to believe that DCs (CD11c⁺) were able to phagocytic conidia present in footpad and migrated to regional lymph nodes.

Mixed secondary bacterial infection is associated with severe lesions of chromoblastomycosis in a neglected population from Brazil

Chromoblastomycosis (CBM) is a chronic subcutaneous infection caused by melanotic fungi, affecting mainly rural workers in tropical and subtropical regions. Secondary bacterial infections (SBIs) in CBM lesions bring complications to the disease, but little is known about the agents involved. Fungal and bacterial identification and epidemiological profile of 50 patients with CBM were analyzed in this study. Bacteria were tested for susceptibility to antibacterial drugs. Fonseacea pedrosoi and Rhinocladiella aquaspersa were the fungal agents isolated. 88% of the patients presented SBI. Gram-positive bacteria coinfected mainly upper limbs, and Gram-negative bacteria were more isolated from lower limbs. Streptococcus pyogenes and mixed bacterial microbiota were associated with severe lesions. Staphylococcus aureus was associated with mixed infections and consequently with the severity of the infection. Resistance to β-lactams and methicillin was detected. Our results emphasize the necessity of bacterial culture and susceptibility testing as part of routine monitoring CBM cases.

Study of tissue inflammatory response in different mice strains infected by dematiaceous fungi Fonsecaea pedrosoi

BACKGROUND

Diseases caused by melanized fungi include mycetoma, chromoblastomycosis and phaeohyphomycosis. This broad clinical spectrum depends on the dynamic interactions between etiologic agent and host. The immune status of the host influences on the development of the disease, as, an exemple. phaeohyphomicosis is more frequently observed in immunocompromised patients.

OBJECTIVES

Examine the histological inflammatory response induced by Fonsecaea pedrosoi in several different strains of mice (BALB/c, C57BL/6, Nude and SCID, and reconstituted Nude).

METHODS

Fonsecaea pedrosoi was cultivated on agar gel and a fragment of this gel was implanted subcutaneously in the abdominal region of female adult mice. After infection has been obtained, tissue fragment was studied histopathologically.

RESULTS

There were significant changes across the strains, with the nodular lesion more persistent in Nude and SCID mice, whereas in immunocompetent mice the lesion progressed to ulceration and healing. The histopathological analysis showed a significant acute inflammatory reaction which consisted mainly of neutrophils in the initial phase that was subsequently followed by a tuberculoid type granuloma in immunocompetent mice.

STUDY LIMITATIONS

There is no a suitable animal model for chromoblastomycosis.

CONCLUSIONS

The neutrophilic infiltration had an important role in the containment of infection to prevent fungal spreading, including in immunodeficient mice. The fungal elimination was dependent on T lymphocytes. The re-exposure of C57BL/6 mice to Fonsecaea pedrosoi caused a delay in resolving the infection, and appearance of muriform cells, which may indicate that re-exposure to fungi, might lead to chronicity of infection.

Epidemiology of Subcutaneous Mycoses in Northeast India: A Retrospective Study

Background:

Subcutaneous mycoses, although rare, are frequently reported from northeast India. Their spectrum varies with geographic region.

Materials and Methods:

We evaluated clinical records and histopathological features of subcutaneous mycoses cases seen during April 2013 to March 2017.

Results:

A total of 70 patients (44 males and 26 females) of subcutaneous mycoses were analyzed. Sixty-one percent of patients were 20–60 years old. Duration of the disease ranged from 3 months to 25 years. Most common site of involvement was the lower limb (32, 46%), followed by the upper limb (25, 36%). A history of trauma was obtained from 76% of patients. Eighty-seven percent of patients were from rural area. Ninety-two percent of patients were agricultural workers. There were 30 established cases of chromoblastomycosis and 16 cases of sporotrichosis. In 24 cases, subcutaneous mycosis was suspected clinically and showed some improvement to empirical itraconazole therapy. Multifocal lesions were seen in six patients. Complication of subcutaneous mycoses in the form of invasive squamous cell carcinoma was seen in one patient. On histopathological examination, verrucous hyperplasia was seen in 93% of cases. Granulomas with suppuration were seen in 77% of cases and granulomas without suppuration were seen in 14.3% of cases. Copper penny bodies were appreciated in 42.8% of cases. Fungal culture was positive only in 55.7% of cases. There was growth of Sporothrix schenckii in 16 patients, Fonsecaea sp. in 19, Cladosporium sp. in 3, and Curvularia sp. in 1.

Conclusion:

Chromoblastomycosis was the most common subcutaneous mycoses seen in northeast India followed by sporotrichosis. The diagnosis remained a challenge in a few cases as the culture positivity was very low. Suppurative granulomas in histopathology played a corroborative role. Therapeutic trial of itraconazole for 2 months was worth trying in such cases.

Chromoblastomycosis: an etiological, epidemiological, clinical, diagnostic, and treatment update

Chromoblastomycosis is a chronic, granulomatous, suppurative mycosis of the skin and subcutaneous tissue caused by traumatic inoculation of dematiaceous fungi of the family Herpotrichiellaceae. The species Fonsecaea pedrosoi and Cladophialophora carrionii are prevalent in regions where the disease is endemic. Chromoblastomycosis lesions are polymorphous: verrucous, nodular, tumoral, plaque-like, and atrophic. It is an occupational disease that predominates in tropical and subtropical regions, but there have been several reports of cases in temperate regions. The disease mainly affects current or former farm workers, mostly males, and often leaving disabling sequelae. This mycosis is still a therapeutic challenge due to frequent recurrence of lesions. Patients with extensive lesions require a combination of pharmacological and physical therapies. The article provides an update of epidemiological, clinical, diagnostic, and therapeutic features.

Chromoblastomycosis

Chromoblastomycosis (CBM), also known as chromomycosis, is one of the most prevalent implantation fungal infections, being the most common of the gamut of mycoses caused by melanized or brown-pigmented fungi. CBM is mainly a tropical or subtropical disease that may affect individuals with certain risk factors around the world. The following characteristics are associated with this disease: (i) traumatic inoculation by implantation from an environmental source, leading to an initial cutaneous lesion at the inoculation site; (ii) chronic and progressive cutaneous and subcutaneous tissular involvement associated with fibrotic and granulomatous reactions associated with microabscesses and often with tissue proliferation; (iii) a nonprotective T helper type 2 (Th2) immune response with ineffective humoral involvement; and (iv) the presence of muriform (sclerotic) cells embedded in the affected tissue. CBM lesions are clinically polymorphic and are commonly misdiagnosed as various other infectious and noninfectious diseases. In its more severe clinical forms, CBM may cause an incapacity for labor due to fibrotic sequelae and also due to a series of clinical complications, and if not recognized at an early stage, this disease can be refractory to antifungal therapy.

Chromoblastomycosis in India: Review of 169 cases

Chromoblastomycosis (CBM) is a chronic, progressive, cutaneous and subcutaneous fungal infection following the traumatic implantation of certain dematiaceous fungi. The disease has worldwide prevalence with predominant cases reported from humid tropical and subtropical regions of America, Asia, and Africa. Diagnosis is often delayed or misdirected either due to poor degree of clinical suspicions or clinical simulation of dermatological conditions. The infection is not uncommon in India and several case reports from the sub-Himalayan belt and western and eastern coasts of India have been published; however, very few have reviewed the cases. We reviewed 169 cases published in English literature from India during 1957 through May 2016, including 2 recent cases from our institute. A tremendous increase in the number of reported cases was noticed since 2012, since which, more than 50% of the cases had been published. A majority of the patients (74.1%) were involved in various agricultural activities directly or indirectly. The mean age at presentation was 43.3 years ± 16.0, with male to female ratio of 4.2:1. The duration of disease at the time of presentation varied from 20 days to 35 years. Any history of trauma was recalled only in 33.8% of the studied cases. The lower extremity was the most common site afflicted, followed by the upper extremity. The culture was positive in 80.3% of the cases with Fonsecaea pedrosoi, isolated as the most common fungal pathogen, followed by Cladophialophora carrionii. Although all the commercially available antifungals were prescribed in these cases, itraconazole and terbinafine were the most commonly used, either alone or in combination with other drugs/physical methods, with variable degrees of outcome. Combinations of different treatment modalities (chemotherapy and physical methods) yielded a cure rate of 86.3%. CBM is refractory to treatment and no single antifungal agent or regimen has demonstrated satisfactory results. Increased awareness with early clinical suspicion of the disease and adequate therapy are necessary to improve the outcome. However, depending upon the causative agent, disease severity, and the choice of antifungals, variable outcomes can be observed.

Neglected endemic mycoses

Fungi often infect mammalian hosts via the respiratory route, but traumatic transcutaneous implantation is also an important source of infections. Environmental exposure to spores of pathogenic fungi can result in subclinical and unrecognised syndromes, allergic manifestations, and even overt disease. After traumatic cutaneous inoculation, several fungi can cause neglected mycoses such as sporotrichosis, chromoblastomycosis, mycetoma, entomophthoramycosis, and lacaziosis. Most of these diseases have a subacute to chronic course and they can become recalcitrant to therapy and lead to physical disabilities, including inability to work, physical deformities, and amputations. For many years, paracoccidioidomycosis was considered the most prevalent endemic systemic mycosis in the Americas, but this situation might be changing with recognition of the worldwide presence of Histoplasma capsulatum. Both paracoccidioidomycosis and histoplasmosis can mimic several infectious and non-infectious medical conditions and lead to death if not recognised early and treated. Cutaneous implantation and systemic mycoses are neglected diseases that affect millions of individuals worldwide, especially in low-income countries where their management is suboptimum because challenges in diagnosis and therapeutic options are substantial issues.

Langerhans Cells Express IL-17A in the Epidermis of Chromoblastomycosis Lesions

Chromoblastomycosis (CBM) is a chronic fungal infection that affects skin and subcutaneous tissue, and little is known about the immunological aspects of such lesions. We have previously described the high expression of IL-17 in this group. Understanding the innate immune response of patients with CBM would improve the knowledge of its immunopathogenesis and contribute to the most appropriate therapies. Nineteen biopsies of verrucous form were obtained from patients with clinical and histopathological diagnosis of CBM, without treatment. This was done with a double immunostaining with conventional immunohistochemistry and immunofluorescence technique as well as confocal microscopy to detect Langerin and IL-17 expression. All of the specimens that were analyzed showed expression of Langerin in the epidermis - the same as the control group. However, only the CBM group presented cells expressing CD207 in the dermis. Interestingly, the coexpression of IL-17 and Langerin was visualized along the epidermis and dermis in 100% of the lesion group. We demonstrated for the first time in situ coexpression of IL-17 and Langerin (CD207) in epidermal cells of patients with CBM and speculated on their role as IL-17-producing cells or whether they could be a new subpopulation of dendritic cells distinct from Langerhans cells.

Mycetoma-like chromoblastomycosis: a diagnostic dilemma

OBJECTIVES

Mycetoma and chromoblastomycosis are subcutaneous fungal infections caused by pigmented fungi, common in the tropics and subtropics. Here we report a pregnant woman who presented with a swelling around the ankle joint which was clinically diagnosed as a case of mycetoma; however, further investigations revealed it to be a case of chromoblastomycosis.

METHODS

24 year old primigravida presented with an indurated swelling around the ankle joint with multiple nodules and sinuses draining serosanguinous discharge. There was no improvement with antibiotic therapy or surgical debridement. Patient was investigated in detail including radiographs, KOH smear, pus culture and biopsy for histopathology and fungal culture.

RESULTS

o grains were identified from the discharge and KOH smear was negative for fungal elements. Pus culture revealed no bacterial growth. On the other hand, histopathology and fungal culture confirmed it to be a case of chromoblastomycosis caused by Fonsecaea pedrosoi. Treatment was initiated with terbinafine 250 mg daily, and patient showed excellent response within 6 months of therapy.

CONCLUSION

This unusual mycetoma-like presentation of chromoblastomycosis has not been previously reported in literature and may be attributed to the altered immune status in pregnancy. This should alert the clinician about the need to be vigilant of the atypical presentations of well-known dermatological conditions, especially in special situations like pregnancy.

Immune response in human chromoblastomycosis and eumycetoma - focusing on human interleukin-17A, interferon-gamma, tumour necrosis factor-alpha, interleukin-1 beta and human beta-defensin-2

Knowledge regarding host immune response to chromoblastomycosis and eumycetoma is limited, particularly concerning cytokines and antimicrobial peptides production. This was a retrospective study of 12 paraffin-embedded tissue samples from patients diagnosed with chromoblastomycosis or eumycetoma from histological findings and tissue culture. DNA extraction and polymerase chain reaction (PCR) from tissues were done to evaluate human interleukin-17A (IL-17A), interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and human beta-defensin-2 (HBD-2) expressions. Human beta-actin primer was used for confirming DNA detection, and DNA extracted from psoriasis lesional skin samples was used as positive controls. The twelve paraffin-embedded sections used in this study consisted of five chromoblastomycosis and seven eumycetoma tissues. All PCR reactions showed beta-actin band at 51 bp in all clinical specimens, confirming adequate DNA levels in each reaction. As positive control, the psoriasis skin samples revealed bands for IL-17A at 174 bp, IFN-γ at 273 bp, TNF-α at 360 bp, IL-1β at 276 bp and HBD-2 at 255 bp. For the chromoblastomycosis and eumycetoma tissues, PCR analyses showed IL-17A band at 174 bp in two eumycetoma tissues and HBD-2 band at 255 bp in a chromoblastomycosis tissue. This study demonstrated IL-17A expression in human eumycetoma and HBD-2 expression in human chromoblastomycosis for the first time. However, their role in immune response remains to be elucidated.

Treatment of Refractory Chromomycosis by Isolated Limb Infusion with Melphalan and Actinomycin D

Background:

Chromomycosis is frequently resistant to systemic and local therapies, and advanced bulky disease can compromise limb function.

Methods:

A man developed extensive chromomycosis of the left arm, refractory to multiple systemic and local treatments. Regional chemotherapy with the isolated limb infusion (ILI) technique using melphalan and actinomycin D markedly reduced disease bulk and greatly improved function of the arm over the next 2 months. Repeat ILI was performed 10 months later, again with good improvement in mobility of the elbow and significant debulking of disease. At the present time, there is some persistent but stable disease, which is controlled by heat therapy with disposable pocket warmers. The patient declined any further systemic therapy.

Conclusion:

ILI rapidly reduced disease bulk, restoring the limb to normal function within a few weeks. Although not curative, ILI could be an effective adjunctive treatment for severe chromomycosis in patients resistant to or intolerant of other therapies.

C-type lectin receptors in the control of T helper cell differentiation

Pathogen recognition by C-type lectin receptors (CLRs) expressed by dendritic cells is important not only for antigen presentation, but also for the induction of appropriate adaptive immune responses via T helper (TH) cell differentiation. CLRs act either by themselves or in cooperation with other receptors, such as other CLRs, Toll-like receptors and interferon receptors, to induce signalling pathways that trigger specialized cytokine programmes for polarization of TH cell differentiation. In this Review, we discuss how triggering of the prototypical CLRs leads to distinct pathogen-tailored TH cell responses and how we can harness our expanding knowledge for vaccine design and the treatment of inflammatory and malignant diseases.

Black yeasts and their filamentous relatives: principles of pathogenesis and host defense

Among the melanized fungi, the so-called "black yeasts" and their filamentous relatives are particularly significant as agents of severe phaeohyphomycosis, chromoblastomycosis, and mycetoma in humans and animals. The pathogenicity and virulence of these fungi may differ significantly between closely related species. The factors which probably are of significance for pathogenicity include the presence of melanin and carotene, formation of thick cell walls and meristematic growth, presence of yeast-like phases, thermo- and perhaps also osmotolerance, adhesion, hydrophobicity, assimilation of aromatic hydrocarbons, and production of siderophores. Host defense has been shown to rely mainly on the ingestion and elimination of fungal cells by cells of the innate immune system, especially neutrophils and macrophages. However, there is increasing evidence supporting a role of T-cell-mediated immune responses, with increased interleukin-10 (IL-10) and low levels of gamma interferon (IFN-γ) being deleterious during the infection. There are no standardized therapies for treatment. It is therefore important to obtain in vitro susceptibilities of individual patients' fungal isolates in order to provide useful information for selection of appropriate treatment protocols. This article discusses the pathogenesis and host defense factors for these fungi and their severity, chronicity, and subsequent impact on treatment and prevention of diseases in human or animal hosts.

In situ immune response in human chromoblastomycosis--a possible role for regulatory and Th17 T cells

BACKGROUND

Chromoblastomycosis is a chronic fungal infection that affects skin and subcutaneous tissue. Lesions can be classified in tumorous, verrucous, cicatricial and plaque type. The cellular immune response in the severe form of the disease seems to correlate with a Th2 pattern of cytokines. The humoral immune response also seems to play a role. We intended to explore the populations of regulatory T cells and the Th17 pattern.

METHODOLOGY

Twenty-three biopsies of verrucous form were obtained from patients with clinical, culture and histopathological diagnostic of chromoblastomycosis, without treatment. It was performed an immunohistochemistry method to detect Foxp3, CD25, TGF-β, IL-6, IL-17 and IL-23.

PRINCIPAL FINDINGS

IL-17 was the only cytokine with high expression in CBM when compared to normal skin. The expression of Treg cells, TGF- β, IL-6 and IL-23 were similar to normal skin.

CONCLUSIONS/SIGNIFICANCE

The constitution of a local immune response with high expression of IL-17 and low expression of other cytokines could be at least in part, an attempt to help the immune system against fungal infection. On the other hand, high levels of local immune response mediated by Th17 profile could overcome the role of Treg cells. The inefficient immunomodulation as a consequence of the unbalance by Treg/Th17 cells seems to corroborate with the less effective immune response against fungi.

Plasmacytoid dendritic cells in cutaneous lesions of patients with chromoblastomycosis, lacaziosis, and paracoccidioidomycosis: a comparative analysis

Plasmacytoid dendritic cells (pDCs) are characterized by expression of CD123 and BDCA-2 (Blood Dendritic Cell Antigen 2) (CD303) molecules, which are important in innate and adaptive immunity. Chromoblastomycosis (CBM), lacaziosis or Jorge Lobo's disease (JLD), and paracoccidioidomycosis (PCM), are noteworthy in Latin America due to the large number of reported cases. The severity of lesions is mainly determined by the host's immune status and in situ responses. The dendritic cells studied in these fungal diseases are of myeloid origin, such as Langerhans cells and dermal dendrocytes; to our knowledge, there are no data for pDCs. Forty-three biopsies from patients with CBM, 42 from those with JLD and 46 diagnosed with PCM, were evaluated by immunohistochemistry. Plasmacytoid cells immunostained with anti-CD123 and anti-CD303 were detected in 16 cases of CBM; in those stained with anti-CD123, 24 specimens were obtained from PCM. We did not detect the presence of pDCs in any specimen using either antibody in JLD. We believe that, albeit a secondary immune response in PCM and CBM, pDCs could act as a secondary source of important cytokines. The BDCA-2 (CD303) is a c-type lectin receptor involved in cell adhesion, capture, and processing of antigens. Through the expression of the c-lectin receptor, there could be an interaction with fungi, similar to other receptors of this type, namely, CD207 in PCM and CD205 and CD209 in other fungal infections. In JLD, the absence of expression of CD123 and CD303 seems to indicate that pDCs are not involved in the immune response.

Revisiting the clinical and histopathological aspects of patients with chromoblastomycosis from the Brazilian Amazon region

BACKGROUND AND AIMS

Chromoblastomycosis is a chronic fungal infection caused by species of the family Dematiaceae. Fonsecaea pedrosoi is the most common etiological agent. The objective of this study was to describe the epidemiological and mycological profile of patients with chromoblastomycosis from the Amazon region of Brazil and to correlate the clinical forms with the histopathological findings and severity criteria.

METHODS

Sixty-five patients were submitted to mycological (direct, culture, and microculture) and histopathological (hematoxylin-eosin staining) examination. Severity of the disease was classified according to the criteria proposed by Carrión in 1950.

RESULTS

Most patients were males (93.8%) and laborers (89.2%). There was a predominance of verrucous lesions (55.4%), which were mainly found on the lower limbs (81.5%). Two major types of tissue reaction were observed: a granulomatous reaction characterized by the formation of suppurative granulomas rich in fungal cells, which were almost always seen in verrucous lesions, and a reaction characterized by the formation of tuberculoid granulomas with few parasites, which were mainly found in well-delimited erythematous plaque-like and cicatricial lesions (p = 0.0001). A peculiar type of organized mycotic granuloma was observed in 20 subjects. Suppurative granulomas were more frequently detected in severe lesions (p = 0.0189) and in lesions with a duration of >10 years (p = 0.0408).

CONCLUSIONS

These results suggest that verrucous lesions present a less competent inflammatory tissue response than patients who develop a well-formed tuberculoid reaction. The latter is associated with a more effective immune response as observed in the limited clinical forms of chromoblastomycosis.

Melanin in a meristematic mutant of Fonsecaea monophora inhibits the production of nitric oxide and Th1 cytokines of murine macrophages

Melanin is a complex polymer which is secreted outside or constitutes the structure of fungal cell wall. It is considered as an important virulence factor in opportunistic pathogenic fungi. In this study, one albino mutant (CBS 125149) was generated from a parent meristematic mutant (CBS 122845) of Fonsecaea monophora. Transmission electron microscopy profiles showed that melanin in the parent strains appeared as electron-dense granules which located on the cell wall surface. We extracted the cell wall fractions from the two different strains by an alkali-acid method. The different strains or its cell wall fractions were interacted with the activated RAW264.7. The pigmented strain and its cell wall fraction could reduce the expression of inducible nitric oxide synthase gene and inhibit the synthesis of nitric oxide in vitro (P < 0.05). Exacerbated Th2 and inhibited Th1 response occurred in the interaction between activated RAW264.7 and the pigmented strain or its cell wall fraction. Collectively, our results suggest that melanin plays an important role in escaping the killing of oxidative burst in vitro. The exacerbated Th2 response probably accelerates the persistence of the fungus.

Fungal x host interactions in Chromoblastomycosis: what we have learned from animal models and what is yet to be solved

Animal studies with chromoblastomycosis were initiated together with the first descriptions of the disease. In this editorial commentary, animal models are briefly reviewed, and the available data based on new immunology tools are discussed.

The cell wall fraction from Fonsecaea pedrosoi stimulates production of different profiles of cytokines and nitric oxide by murine peritoneal cells in vitro

Chromoblastomycosis is a chronic, suppurative and granulomatous mycosis whose main etiologic agent is the fungus Fonsecaea pedrosoi. The severity of chromoblastomycosis clinical manifestations correlates with the Th1 or Th2 immune response, and an efficient cellular immune response depends on the interaction between immune cells and the cell wall of the fungi, which is able to promote this activation. The objective of this study was to analyze the influence of cell wall fractions of Fonsecaea pedrosoi on the activation of peritoneal phagocytes obtained from mice. Our results revealed that after 4 h of inoculation with fungal cell wall components, there was a cell migration predominantly comprised of neutrophils followed, after 72 h, by migration of the macrophages. After 4 h, the F2 fraction caused increased production of nitric oxide in phagocytes, but this effect was not observed in the phagocytes after 72 h. The F1 fraction stimulated production of IL-12 in cells that migrated after 72 h, while the inactivated fungus and the F2 fraction led to production of IL-10. The F2 fraction decreased the rate of phagocytosis and increased the production of IL-10. Our results suggest that the F2 fraction and its components caused an important disruption of microbicidal mechanisms negatively modulating the immune response and favoring the persistence of the fungus.

Human visceral leishmaniasis expresses Th1 pattern in situ liver lesions

The architectural and infiltrate pattern of liver human visceral leishmaniasis (HVL) have been systematically classified as typical, fibrogenic or nodular. Despite this histopathological classification, the immune response based on cytokines and cellular phenotypes have never been performed. The aim of this study was to determine the immunophenotypic pattern and cytokine profile of the nodular involvement of the liver in HVL. We evaluated nine cases of the nodular form of HVL. In situ immune response was studied through cytokine analysis and immunohistochemical study for phenotype markers: IL-1, IL-4, IL-10, TNF-alpha, IFN-gamma, CD4+ T cells, CD8+ T cells, CD20, CD68, CD57 and macrophage activation was determined by evaluation of iNOS activity. HVL seems to be related to a better immune response. Amastigotes were rarely found on liver sections. Leishmania antigen expression was also rare and located in the inflammatory nodules. The lower expression of IL-4 and IL-10, moderate expression of TNF-alpha and IFN-gamma demonstrate a panorama of Th1 phenotype. The increased expression of NK cells could help in sustaining this model of response. This pattern of immune response is probably responsible for improvement in the parasite's clearance from liver tissue and it is a prognostic marker of human visceral leishmaniasis.

Fonsecaea pedrosoi infection induces differential modulation of costimulatory molecules and cytokines in monocytes from patients with severe and mild forms of chromoblastomycosis

The host defense mechanism in chromoblastomycosis has not been thoroughly investigated. It has been suggested that cell-mediated immunity in patients with long-standing chromoblastomycosis is somehow impaired. As a result, these individuals became unable to develop an efficient immune reaction. Many studies have shown that monocyte-derived macrophages exhibit critical activities in immunity to microorganisms. Moreover, the ability of cells from the monocytic lineage to process and present antigens, to produce cytokines, and to provide costimulatory signals confirms their pivotal role in the initiation of specific immune responses. In the present study, it was observed that monocytes from patients with a severe form of disease had a higher production of IL-10 and a lower expression of HLA-DR and costimulatory molecules when stimulated with specific antigen or LPS. Immune modulation with recombinant IL-12 or anti-IL-10 can restore the antigen-specific Th1-type immune response in chromoblastomycosis patients by up-regulating HLA-DR and costimulatory molecules in monocytes. Therefore, our data show that monocytes from patients with different clinical forms of chromoblastomycosis present distinct phenotypic and functional profiles. This observation suggests possible mechanisms that control the T cell response and influence their role in the development of pathology.

Cryptic "chromo-fibroma"

Chromoblastomycosis is an uncommon chronic fungal infection capable of presenting in a variety of clinical guises. Herein, we present the histopathological features of an unusual dermal response engendered by this organism, consisting of dermal effacement by a spindle cell proliferation arranged in sweeping fascicles.

Macrophage and TGF-beta immunohistochemical expression in Jorge Lobo's disease

Jorge Lobo's disease, or lacaziosis, is a chronic deep mycosis that clinically manifests as solid, variable-sized nodular parakeloidal lesions. Few studies have characterized the in situ cellular and humoral immune response, especially the involvement of cytokines with immunosuppressive effects such as TGF-beta. The objective this paper was to analyze the expression of TGF-beta in cutaneous lesions in lacaziosis and investigate its importance in the etiopathogy of the disease. The results indicate that the abundance of collagen bands, together with weak immunolabeling for CD68 seen in macrophages, indicates a concomitant effect of TGF-beta inhibiting macrophages and inducing fibrosis, which is responsible for the keloid aspect frequently acquired by these lesions. Finally, the evolution of the infection supports the hypothesis that TGF-beta plays a fundamental role in the etiopathology of Lacazia loboi infection, either by inhibiting the cellular immune response mainly mediated by macrophages or by inducing fibrosis. Further studies are necessary to better characterize the phenotype of the inflammatory infiltrate as well as the participation of other cytokines and growth factors in the tissue response of the host in Jorge Lobo's disease.

The pattern of immune cell infiltration in chromoblastomycosis: involvement of macrophage inflammatory protein-1 alpha/CCL3 and fungi persistence

Chromoblastomycosis (CR) is a subcutaneous chronic mycosis characterized by a granulomatous inflammatory response. However, little is known regarding the pattern of leukocyte subsets in CR and the pathways involved in their recruitment. The objective of this study was to assess the cellular subsets, chemokine, chemokine receptors and enzymes in CR. The inflammatory infiltrate was characterized by immunohistochemistry using antibodies against macrophages (CD68), Langerhans'cells (S100), lymphocytes (CD3, CD4, CD8, CD45RO, CD20 and CD56) and neutrophils (CD15). The expression of MIP-1alpha (Macrophage inflammatory protein-1alpha), chemokine receptors (CXCR3 and CCR1) and enzymes (superoxide dismutase-SOD and nitric oxide synthase-iNOS) was also evaluated by the same method. We observed an increase in all populations evaluated when compared with the controls. Numbers of CD15(+) and CD56(+) were significantly lower than CD3(+), CD4(+), CD20(+) and CD68(+) cells. Statistical analysis revealed an association of fungi numbers with CD3, CD45RO and iNOS-positive cells. Furthermore, MIP-1alpha expression was associated with CD45RO, CD68, iNOS and CXCR3. Our results suggest a possible role of MIP-1alpha and fungi persistence in the cell infiltration in CR sites.

Biology and pathogenesis of Fonsecaea pedrosoi, the major etiologic agent of chromoblastomycosis

Fonsecaea pedrosoi is the principal etiologic agent of chromoblastomycosis, a fungal disease whose pathogenic events are poorly understood. Treatment of the disease presents poor effectiveness and serious side effects. The disease is epidemiologically important in several regions, which has stimulated studies focused on the biology and pathogenic potential of its major causative agent. In this review, we summarize the current knowledge on the biological aspects of F. pedrosoi, including cell differentiation and pathogenic mechanisms during the interaction of fungi with different hosts' elements.

Absence of CD4+ T cells impairs host defence of mice infected with Fonsecaea pedrosoi

Chromoblastomycosis is a human chronic, often debilitating, suppurative, granulomatus mycosis of the skin and subcutaneous tissues beginning after inoculation trauma. It occurs worldwide, but is more frequently observed in tropical countries such as Brazil. Some studies have focused on fungus-host interaction, showing a predominantly cell-mediated immune response, with the activation of macrophages involved in fungus phagocytosis. Immunization with live conidia produced a high influx of CD4 T cells into the draining lymph node. The sensitized T cells proliferate in vitro when restimulated with specific antigen and preferentially produce IFN- gamma. To better characterize the role played by T cells on the chromoblastomycosis infection we used mice deficient for CD4 and CD8. Data determined by CFU counts associated with decreased DTH and IFN-gamma production of infected mice clearly demonstrated that, during experimental F. pedrosoi infection, absence of CD4(+) cells induces a more severe disease.

Molecular analysis and pathogenicity of the Cladophialophora carrionii complex, with the description of a novel species

Cladophialophora carrionii is one of the four major etiologic agents of human chromoblastomycosis in semi-arid climates. This species was studied using sequence data of the internal transcribed spacer region of rDNA, the partial beta-tubulin gene and an intron in the translation elongation factor 1-alpha gene, in addition to morphology. With all genes a clear bipartition was observed, which corresponded with minute differences in conidiophore morphology. A new species, C. yegresii, was introduced, which appeared to be, in contrast to C. carrionii, associated with living cactus plants. All strains from humans, and a few isolates from dead cactus debris, belonged to C. carrionii, for which a lectotype was designated. Artificial inoculation of cactus plants grown from seeds in the greenhouse showed that both fungi are able to persist in cactus tissue. When reaching the spines they produce cells that morphologically resemble the muriform cells known as the "invasive form" in chromoblastomycosis. The tested clinical strain of C. carrionii proved to be more virulent in cactus than the environmental strain of C. yegresii that originated from the same species of cactus, Stenocereus griseus. The muriform cell expressed in cactus spines can be regarded as the extremotolerant survival phase, and is likely to play an essential role in the natural life cycle of these organisms.

Human leukocyte antigen class I and MICA haplotypes in a multicase family with Cladophialophora carrionii chromoblastomycosis

Previous studies carried out in an endemic semiarid region northwest of Venezuela at Falcon State have shown a prevalence of 15.4/1000 of chromoblastomycosis following traumatisms with xenophile vegetation infected with Cladophialophora carrionii. We performed high-resolution DNA typing of human leukocyte antigen (HLA)-A, -B and -C and major histocompatibility complex class I chain related gene A (MICA) alleles and segregation analysis in 49 members of one extended family with 12 affected individuals, who have lived for approximately 70 years in this endemic zone. None of the alleles, haplotypes or genotypes is shared by all the patients. No deviation from the expected HLA haplotype distribution or association of chromoblastomycosis with HLA-A, -B and -C haplotypes was observed. Further, a haplotype-sharing transmission/disequilibria testing of 11 nuclear families did not give enough evidence to claim linkage (P = 0.398), suggesting that genes located in the short arm of chromosome 6 may not be relevant in the immune response toward infection with C. carrionii in this Venezuelan endemic zone. Deleted MICA alleles on HLA-B*4802 haplotypes were present among several members of the extended family, but only two of them were affected.

Inhibition of Nitric Oxide Production by Macrophages in Chromoblastomycosis: A Role for Fonsecaea pedrosoi Melanin

Chromoblastomycosis is a chronic and progressive deep mycosis that is usually found in tropical and subtropical areas. Fonsecaea pedrosoi is considered its most frequent etiologic agent and causes a typical granulomatous inflammatory response, whose degree reflects the immune status of the host. Since macrophages play a fundamental role in the control of the infection, this study aimed at investigating the production of oxygen reactive specimens, the phagocytic capacity and the production of nitric oxide (NO) by macrophages employing in vitro assays and an in vivo model of chromoblastomycosis. Our results demonstrated that, during the infection, peritoneal macrophages show an increased phagocytic capacity and H2O2 production, but also a reduced ability to produce NO. Moreover, F. pedrosoi stimulated H2O2 production in vitro but not the synthesis of NO. The incubation of IFNgamma and LPS-stimulated macrophages with melanin, obtained from the fungus, inhibited NO production. Examination of the liver and spleen of infected animals, at day 30 or 60 following inoculation, showed a progressive increase in the number and size of granulomas, indicating that macrophages are properly mobilized and activated. Our data suggest that the inability of the host to clear F. pedrosoi, leading to a chronic disease, is due, at least in part, to the inhibition of NO synthesis by macrophages by fungus-produced melanin.

Management of chromoblastomycosis: novel perspectives

PURPOSE OF REVIEW

Significant advances in knowledge of chromoblastomycosis and its etiologic agents have been made in the past 5 years. New explanations and approaches that could resolve persisting medical challenges for this orphan disease are reviewed here.

RECENT FINDINGS

In recent years advances have been made regarding the taxonomy and ecoepidemiology of the etiologic agents, basic knowledge of the pathogenesis of the lesions, especially the fibrotic process, and the immunologic response to chromoblastomycosis. Conversely there have been no recent significant advances in knowledge of the genetic polymorphism of the wild isolates or in development of experimental models, impairing the possibility of in-depth clinicopathologic investigations. As a result medical management is dependent on the development of diagnostic and therapeutic tools developed for other fungal diseases.

SUMMARY

Recent findings are applicable in laboratory and medical practice. Benefits can accrue to basic knowledge from data collected on other cutaneous diseases of parasitic or bacterial origin.

Antigen distribution and antigen-presenting cells in skin biopsies of human chromoblastomycosis

BACKGROUND

Chromoblastomycosis is a chronic, suppurative, granulomatous mycosis usually confined to skin and subcutaneous tissues. The host defense mechanisms in chromoblastomycosis have not been extensively investigated. The purpose of the present study was to determine the distribution and pathways of the fungal antigen(s) and the possible role of the different immunocompetent cells in antigen processing in skin lesions.

METHODS

The distribution of Fonsecaea pedrosoi antigen(s) in human skin was studied in 18 biopsies from 14 patients with chromoblastomycosis. A purified polyclonal immune serum raised in rabbits against metabolic antigen(s) of F. pedrosoi was used to detect yeast antigen(s) by immunohistochemical procedures. Double immunolabeling was performed with yeast antigen(s) and Langerhans' cells [labeled with anti-S100 protein monoclonal antibody (MoAb)], yeast antigen(s) and factor XIIIa+ dermal dendrocytes (immunolabeled with anti-factor XIIIa polyclonal antibody), and yeast antigen(s) and macrophages (labeled with CD 68 monoclonal antibody).

RESULTS

The F. pedrosoi antigen(s) accumulated in the skin macrophages and, in a few instances, in factor XIIIa+ dendrocytes and Langerhans' cells.

CONCLUSIONS

The data obtained suggest that chiefly macrophages, also Langerhans' cells and factor XIIIa+ dermal dendrocytes, function as antigen-presenting cells in chromoblastomycosis.