Micoses superficiais e os elementos da resposta imune

Spatio-temporal six-year retrospective study on dermatophytosis in Rio de Janeiro, Southeast Brazil: A tropical tourist locality tale

Trichophyton, Microsporum, Nannizzia and Epidermophyton genera cause dermatophytosis, the most common and highly contagious infectious skin disease. Rio de Janeiro is one of the most visited cities in the Southern Hemisphere, located in the most visited state of Brazil. This retrospective study investigated epidemiological and laboratorial aspects of dermatophytosis in Rio de Janeiro state, Brazil, by using spatiotemporal analysis. More than half of all individuals were infected by one or more dermatophytes. A variation between 18 and 106 years-old of the studied population was verified, and women more frequently affected. Patients were more frequently infected by Trichophyton spp., most of them T. rubrum, followed by T. mentagrophytes. M. canis and N. gypsea were more frequently isolated in the age group between 40 and 60 years old, while T. rubrum predominates among younger patients. All species presented homogeneous distribution while T. tonsurans appears to be restricted to the Rio de Janeiro capital while E. floccosum to the municipality of Macaé (190 Km apart from RJ). Rio de Janeiro state presented spatial clusters of dermatophytosis with high density in Guanabara Bay (E. floccosum, M. canis, N. gypsea, T. tonsurans) and Niterói (T. rubrum, T. mentagrophytes) but low density in Macaé (E. floccosum). Significant spatiotemporal clusters on dermatophytosis cases were detected in distinct municipalities (p-value ≤ 0.05). The Vulnerability Index (r = 0.293) and Demographic Density (r = 0.652) distributed according to neighborhoods in Niterói were direct related with dermatophytosis cases whereas Income (r = -0.306) was inversely correlated (p-value ≤ 0.05). The dermatophytosis spatiotemporal distinct distribution after two major international events in Rio de Janeiro, Brazil, highlight the pressing need for specific measures of its prevention and controlling. This is particularly relevant in touristic tropical localities which must consider both socio-economical and traveler's medicine variables.

Detection of IL-17A and IL-17F gene polymorphism in recurrent and disseminated pityriasis versicolor: a case-control study

Recurrent and disseminated pityriasis versicolor (RDPV) is a common clinical entity, characterized by its recurrent and disfiguring nature. Studies demonstrated host genetic variations in the immune response, especially the role of IL-17 in antifungal immunity. This study aimed to detect whether IL-17A and F gene polymorphisms are found in cases of RDPV. It included 100 cases of RDPV and 100 age and sex matched controls, from which EDTA blood samples were taken for single-nucleotide polymorphism analysis. IL-17A (rs2275913) and F (rs763780) were associated with a significantly increased incidence of developing RDPV. IL-17A and F gene polymorphism could be implicated as a risk factor for the development of RDPV.

Prophylaxis and Therapeutic Ability of Inactivated Dermatophytic Vaccine Against Dermatophytosis in the Rabbits as an Animal Model

Objectives

Dermatophytosis is a group of cutaneous diseases widely distributed in human and animals. It causes serious infection in some human cases and economic losses in farm animals. The primary aim of this study is to conduct an investigation of prophylaxis and a potential therapeutic vaccine against dermatophytosis.

Materials and Methods

The rabbit was chosen as an animal model of dermatophytosis for a case control study conducted in two parts. Inactivated cells of Trichophyton mentagrophytes were prepared for use as a vaccine. The prophylaxis part included vaccination of rabbits with the prepared vaccine either alone or with Freund's adjuvant, followed by infection with the same fungus. The second part included treatment of infected rabbits with an inactivated vaccine.

Results

The prepared vaccine showed prophylactic ability against infection with T. mentagrophytes for more than 6 months without requiringan adjuvant and also revealed at herapeutic ability in infected animals after a short time (16 days), compared with the control group.

Conclusion

Inactivated vaccine gives animals durable protection and shortens the treatmenttime for infection with dermatophytosis.

Immunopathogenesis of Dermatophytoses and Factors Leading to Recalcitrant Infections

The pathogenesis of dermatophytic infections involves the interplay of three major factors: the dermatophyte, the inherent host defense, and the adaptive host immune response. The fungal virulence factors determine the adhesion and invasion of the skin while the immune response depends on an interaction of the pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMP) with pattern recognition receptors (PRRs) of the host, which lead to a differential Th (T helper) 1, Th2, Th17, and Treg response. While anthropophilic dermatophytes Trichophyton rubrum and now increasingly by T. interdigitale subvert the immune response via mannans, zoophilic species are eliminated due to a brisk immune response. Notably, delayed-type hypersensitivity (Th1) response of T lymphocytes causes the elimination of fungal infection, while chronic disease caused by anthropophilic species corresponds to toll-like receptor 2 mediated IL (interleukin)-10 release and generation of T-regulatory cells with immunosuppressive potential. Major steps that determine the ultimate clinical course and chronicity include genetic susceptibility factors, impaired epidermal and immunological barriers, variations in the composition of sebum and sweat, carbon dioxide tension, skin pH, and topical steroid abuse. It is important to understand these multifarious aspects to surmount the problem of recalcitrant dermatophytosis when the disorder fails conventional therapeutic agents.

Cellular and Molecular Response of Macrophages THP-1 during Co-Culture with Inactive Trichophyton rubrum Conidia

Trichophyton rubrum is causing an increasing number of invasive infections, especially in immunocompromised and diabetic patients. The fungal invasive infectious process is complex and has not yet been fully elucidated. Therefore, this study aimed to understand the cellular and molecular mechanisms during the interaction of macrophages and T. rubrum. For this purpose, we used a co-culture of previously germinated and heat-inactivated T. rubrum conidia placed in contact with human macrophages cell line THP-1 for 24 h. This interaction led to a higher level of release of interleukins IL-6, IL-2, nuclear factor kappa beta (NF-κB) and an increase in reactive oxygen species (ROS) production, demonstrating the cellular defense by macrophages against dead fungal elements. Cell viability assays showed that 70% of macrophages remained viable during co-culture. Human microRNA expression is involved in fungal infection and may modulate the immune response. Thus, the macrophage expression profile of microRNAs during co-culture revealed the modulation of 83 microRNAs, with repression of 33 microRNAs and induction of 50 microRNAs. These data were analyzed using bioinformatics analysis programs and the modulation of the expression of some microRNAs was validated by qRT-PCR. In silico analysis showed that the target genes of these microRNAs are related to the inflammatory response, oxidative stress, apoptosis, drug resistance, and cell proliferation.

In situ immune response in human dermatophytosis: possible role of Langerhans cells (CD1a+) as a risk factor for dermatophyte infection

Dermatophytosis is a cutaneous mycosis caused by a plethora of keratinophilic fungi, but Trichophyton rubrum is the most common etiological agent. Despite its high prevalence worldwide, little is known about the host defense mechanisms in this infection, particularly the in situ immune response. Using an immunohistochemistry approach, we investigated the density of CD1a+, factor XIIIa+ and CD68+ cells in the skin of dermatophytosis patients. Langerhans cells (CD1a+ cells) were significantly decreased in the epidermis of patients, both in affected and unaffected areas. In the dermis, however, no differences in the density of macrophages (CD68+ cells) and dermal dendrocytes (factor XIIIa+ cells) were observed. These results suggest that the decreased number of Langerhans cells may be a risk factor for development of dermatophytosis.

Fungal evolution: major ecological adaptations and evolutionary transitions

Fungi are a highly diverse group of heterotrophic eukaryotes characterized by the absence of phagotrophy and the presence of a chitinous cell wall. While unicellular fungi are far from rare, part of the evolutionary success of the group resides in their ability to grow indefinitely as a cylindrical multinucleated cell (hypha). Armed with these morphological traits and with an extremely high metabolical diversity, fungi have conquered numerous ecological niches and have shaped a whole world of interactions with other living organisms. Herein we survey the main evolutionary and ecological processes that have guided fungal diversity. We will first review the ecology and evolution of the zoosporic lineages and the process of terrestrialization, as one of the major evolutionary transitions in this kingdom. Several plausible scenarios have been proposed for fungal terrestralization and we here propose a new scenario, which considers icy environments as a transitory niche between water and emerged land. We then focus on exploring the main ecological relationships of Fungi with other organisms (other fungi, protozoans, animals and plants), as well as the origin of adaptations to certain specialized ecological niches within the group (lichens, black fungi and yeasts). Throughout this review we use an evolutionary and comparative-genomics perspective to understand fungal ecological diversity. Finally, we highlight the importance of genome-enabled inferences to envision plausible narratives and scenarios for important transitions.

Repositioning the Old Fungicide Ciclopirox for New Medical Uses

BACKGROUND

Ciclopirox (CPX) has been used as an antifungal agent in various formulations to treat superficial fungal infection for decades. Its effectiveness and safety in treatments have been demonstrated by multiple studies.

METHODS

Here we briefly summarize the pharmacological and toxicological properties of CPX as an antifungal agent, the new medical uses of CPX, as well as the correspondent molecular mechanisms.

RESULTS

Increasing evidence has demonstrated that CPX is able to inhibit tumor growth, ameliorate diabetes and its complications, prevent human immunodeficiency virus (HIV) infection, and improve age-associated cardiovascular defects. Interestingly, its antifungal activity and all those newly observed effects are more or less related to its capability of chelating iron and interfering with the related signaling pathways. Mechanistically, CPX is capable of modulating the activities of certain enzymes or signaling pathways, such as ribonucleotide reductase (RR), deoxyhypusine hydroxylase (DOHH)/eukaryotic translation initiation factor 5A (eIF5A), Wnt/β-catenin, hypoxia-inducible factor-1α (HIF-1 α)/vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 3 (VEGFR-3)/extracellular signal-regulated protein kinases 1/2, mammalian target of rapamycin, and cyclin dependent kinases (CDKs). Most of these activities are related to its chelation of iron.

CONCLUSION

CPX, as an antifungal agent, may be repositioned for treatment of cancer and other human diseases.

Is Antifungal Resistance a Cause for Treatment Failure in Dermatophytosis: A Study Focused on Tinea Corporis and Cruris from a Tertiary Centre?

Background:

Dermatophytoses are one of the most common skin diseases that have been largely simple to treat. However, in recent years, these infections have become recalcitrant to treatment which can possibly be due to antifungal resistance.

Aim:

To analyze the resistance pattern of patients with recalcitrant dermatophytoses.

Materials and Methods:

A cross-sectional evaluation was undertaken of 40 consecutive patients with recalcitrant tinea corporis/cruris/both who had taken systemic antifungal treatment and did not respond completely to therapy or had recurrent lesion within 1 month of stopping the therapy. Terbinafine, fluconazole, itraconazole, ketoconazole, amphotericin B, and voriconazole were the antifungals tested using broth microdilution assay for antifungal susceptibility testing of dermatophytes, and MIC50, 90 values were recorded.

Results:

KOH mount was positive in 18 (45%) patients, culture was positive in 28 (70%) patients. Trichophyton mentagrophytes (35%) and T. rubrum (27.5%) were the predominant isolates. Overall, activity of terbinafine and itraconazole were significantly higher than the other drugs tested. For terbinafine, both T. mentagrophytes and T. rubrum were inhibited at MIC₉₀ of 0.125 μg/ml. Itraconazole-inhibited T. mentagrophytes and T. rubrum at MIC₉₀ of 0.0625 and 0.25 μg/ml, respectively. All isolates had reduced susceptibility to fluconazole.

Conclusion:

While MIC seen were higher than western data, in-vitro resistance (>1 μg/ml) to antifungals was not seen and probably may not be a cause of treatment failure. Possibly, treatment failure lies in the intricate host fungal interaction and virulence of species which help it to evade host immune response.

Recurrent and disseminated pityriasis versicolor: A novel clinical form consequent to Malassezia-host interaction?

Pityriasis versicolor is a superficial fungal infection caused by Malassezia spp. The aim of this study is to propose the definition of a new clinical entity: the recurrent and disseminated pityriasis versicolor (RDPV). All patients with RDPV were enrolled over an eight-month period. Clinical and epidemiological data were obtained, Malassezia (M.) species were isolated in cultures and identified by phenotypic and molecular characterization, skin biopsies were taken from active lesions, serum levels of immunoglobulin E were obtained and therapeutic schemes were evaluated. A total of 16 patients were included (11 male, 5 female). The most frequently isolated species were M. japonica (n = 3) and M. furfur (n = 3). This is the first study that isolates M. japonica in patients with pityriasis versicolor; interestingly, those were recalcitrant patients. Seven patients (43.8%) had no cure with any of the proposed treatments; among those, 5 (71.4%) had increased serum IgE levels. The most effective treatment was itraconazole 200 mg daily for 28 days. The RDPV has very different features from the classic form, including a poor response to treatment, and the isolation of different Malassezia species; therefore, we propose a hypothesis for the definition of a new clinical condition (RDPV), which could be a result of the interaction Malassezia-host.

Exfoliative erythroderma and palmoplantar hyperkeratosis associated with Majocchi's granuloma by Trichophyton tonsurans in a patient with AIDS

BACKGROUND

Dermatophytoses are skin superficial mycoses in which clinical manifestations are directly related to the virulence of the infecting microorganism or the host immunity.

CASE REPORT

We describe a severe case of dermatophytosis associated with exfoliative erythroderma, substantial palmoplantar keratoderma, onychodystrophy affecting all nails, diffuse non-scarring alopecia and tissue fungal invasion by Trichophyton tonsurans, which led us to the diagnosis of AIDS. Direct examination and culture for fungi from skin scraping from two different sites were performed. Biopsy and histopathological exam were also performed on three different sites. Direct examination of the lesions' scraping revealed septate hyaline hyphae and arthroconidia, identified as Trichophyton tonsurans by culture in glucose Sabouraud agar and Mycosel agar. A scalp biopsy revealed follicular fungal invasion and Majocchi's granuloma. Due to the severity of the presentation we requested an anti-HIV serology, which was positive. The patient was treated with itraconazole, 200mg/day, for 120 days, which promoted a complete regression of the lesions.

CONCLUSIONS

Severe and atypical forms of dermatophytosis could lead to a diagnosis of AIDS.

Are Th17 Cells Playing a Role in Immunity to Dermatophytosis?

Despite their superficial localization in the skin, pathogenic dermatophytes can induce a complex but still misunderstood immune response in their hosts. The cell-mediated immunity (CMI) is correlated with both clinical recovery and protection against reinfection, and CD4+ T lymphocytes have been recognized as a crucial component of the immune defense against dermatophytes. Before the discovery of the Th17 pathway, CMI was considered to be only dependent of Th1 cells, and thus most studies on the immunology of dermatophytosis have focused on the Th1 pathway. Nevertheless, the fine comparative analysis of available scientific data on immunology of dermatophytosis in one hand and on the Th17 pathway mechanisms involved in opportunistic mucosal fungal infections in the other hand reveals that some key elements of the Th17 pathway can be activated by dermatophytes. Stimulation of the Th17 pathway could occur through the activation of some C-type lectin-like receptors and inflammasome in antigen-presenting cells. The Th17 cells could go back to the affected skin and by the production of signature cytokines could induce the effector mechanisms like the recruitment of polymorphonuclear neutrophils and the synthesis of antimicrobial peptides. In conclusion, besides the Th1 pathway, which is important to the immune response against dermatophytes, there are also growing evidences for the involvement of the Th17 pathway.

Dermatophytosis in patients with human immunodeficiency virus infection: clinical aspects and etiologic agents

Dermatophytosis in individuals with human immunodeficiency virus infection seems to manifest with atypical, multiple, or extensive lesions more frequently. In addition, there are reports of presentations with little inflammation, called anergics. Less common etiologic agents have been isolated in these individuals, such as Microsporum species. To describe clinical aspects and etiologic agents of dermatophytosis in individuals with human immunodeficiency virus (HIV) infection. Patients with clinical diagnosis of dermatophytosis underwent scarification for mycological diagnosis through direct microscopic examination and fungal isolation in culture on Sabouraud dextrose agar. Sixty individuals had a clinical hypothesis of dermatophytosis. In 20 (33.3%) of the 60 patients, dermatophytosis was confirmed through a mycological study. Tinea corporis, diagnosed in 14 patients, was the most frequent clinical form, followed by tinea unguium in 7, tinea cruris in 5, and tinea pedis in 1 patient. Most of the lesions of tinea corporis were anergic. Five patients with tinea unguium had involvement of multiple nails, with onychodystrophy as the predominant subtype. Multiple cutaneous lesions occurred in 3 patients and extensive cutaneous lesions in 4. Regarding the agent, Trichophyton rubrum was the most commonly isolated. The high occurrence of anergic skin lesions and involvement of multiple nails, especially as onychodystrophy, corroborates the hypothesis that atypical, disseminated, and more severe presentations are common in individuals with HIV infection. However, no Microsporum species was isolated even in atypical, extensive, or disseminated cases, in disagreement with previous reports. Therefore, the approach of squamous lesions in HIV-positive patients must include a mycological study, in view of the possibility of anergic dermatophytosis, to promote the introduction of a suitable therapeutic agent.

Dermatomycoses and inflammation: The adaptive balance between growth, damage, and survival

Dermatomycosis is characterized by both superficial and subcutaneous infections of keratinous tissues and mucous membranes caused by a variety of fungal agents, the two most common classes being dermatophytes and yeasts. Overall, the stepwise process of host infection is similar among the main dermatomycotic species; however, the species-specific ability to elicit a host reaction upon infection is distinct. Yeasts such as Candida albicans elicit a relatively low level of host tissue damage and inflammation during pathogenic infection, while dermatophytes may induce a higher level of tissue damage and inflammatory reaction. Both pathogens can, however, manipulate the host's immune response, ensuring survival and prolonging chronic infection. One common element of most dermatomycotic infections is the disease burden caused by inflammation and associated signs and symptoms, such as erythema, burning and pruritus. There is a strong clinical rationale for the addition of a topical corticosteroid agent to an effective antimycotic therapy, especially in patients who present with inflammatory dermatomycoses (e.g., tinea inguinalis). In this review, we aim to compare the pathogenesis of common dermatomycotic species, including Candida yeasts (Candida albicans), dermatophytes (Trichophyton, Epidermophyton or Microsporum species), and other pathogenic yeasts (Malassezia), with a special focus on unique species-specific aspects of the respective infection processes, the interaction between essential aspects of pathogenic infection, the different roles of the host inflammatory response, and the clinical consequences of the infection-related tissue damage and inflammation. We hope that a broader understanding of the various mechanisms of dermatomycoses may contribute to more effective management of affected patients.

Expression of antimicrobial peptides and toll-like receptors is increased in tinea and pityriasis versicolor

In superficial tinea and pityriasis versicolor, the causative fungi are for the most part confined to the stratum corneum which is barely reached by leukocytes. Therefore, a role of non-cellular components in the epidermal antifungal defence was suggested. To investigate the presence of such factors in these infections, the expression of human beta defensins 2 and 3 (hBD-2, hBD-3), RNase 7, psoriasin, toll-like receptors 2, 4 and 9 (TLR2, TLR4 and TLR9) and dectin 2 was analysed by use of immunostainings in skin biopsies. We found that hBD2, hBD3, psoriasin, RNase7, TLR2 and TLR4 were significantly more often expressed in distinct layers of lesional epidermis as compared with uninfected epidermis. In both infections but not in normal skin, hBD2 and hBD3 were commonly expressed within the stratum corneum and in the stratum granulosum. Similarly, psoriasin was seen more often in the upper skin layers of both infections as compared with normal skin. No significant differences between normal and infected skin were found for the expression of TLR9 and dectin 2. Our findings clearly show the expression of specific antimicrobial proteins and defence-related ligands in superficial tinea as well as in pityriasis versicolor, suggesting that these factors contribute to fungal containment.

Is fungal foot infection the initiating and maintaining cause of knee osteoarthritis?

So far fungal foot infection (FFI) has been considered as troubling, however, not dangerous, by the general public as well as doctors. Nevertheless, new immunology information and anatomy dispositions led us to the distinct suspicions. We propose a FFI-induced knee joint osteoarthritis (OA) model. We suppose repeated recurrences of fungal foot disease to be the initiating immunology impulse. The aim of the work is to introduce a new model and to determine antigen epitopes initiating and maintaining the knee OA using computer simulation. Freely accessible immunological databases and servers were used in this search. Presentable antigen epitopes in Trichophyton rubrum dermatophyte products were identified for molecules of the six most abundant alleles of DRB1 locus of human major histocompatibility complex. Subsequently, similar sequences in human joint peptides (collagens, aggrecan and others) were matched to these antigen epitopes by a comparative program. A number of pairs with very similar fungal and joint peptide sequences, supposed to initiate and maintain the knee OA antigen epitopes, were found. A FFI-induced knee joint OA model is shown to the medical community which can initiate further discussion, research and practical verification.