Characterisation of the inflammatory cell infiltrate in chronic hyperplastic candidosis of the oral mucosa

"The Standard Procedure" for Investigation of Oral Neutrophils in Oral Diseases

Aim

There is need of an objective "standard procedure" that is reliable and clinically applicable for estimating oral neutrophil content in relation to oral diseases.

Methods

Forty-one patients with suspected oral candidosis (OC) and nine healthy controls with no oral mucosal disease were flushing with 10 ml mouth rinse (MR) (sterile phosphate-buffered saline) for 1 min. Aliquots were stored on different conditions to explore stability, storage, and fixation conditions for analysis by flow cytometry.

Results

The optimal storage and fixation condition for MR was by fixation 1 : 1 in 10% formalin and stored at 5°C. This procedure yielded stable results up to 7 days after collection. The ability of the optimized method to relate oral neutrophils to inflammation was demonstrated by the significantly higher number of neutrophils in patients with primary OC (p = 0.0334) compared to healthy controls.

Conclusion

This method is rapid, reliable, and clinically applicable for establishing the content of oral neutrophils. We demonstrate increased density of oral neutrophils in the MR of patients with OC. The potential of the method is to be "the standard procedure" for investigation of the oral inflammation in patients with oral diseases as it is noninvasive and provides high stability, clinical relevance, and minimal handling.

Host's Immunity and Candida Species Associated with Denture Stomatitis: A Narrative Review

Denture-related Candida stomatitis, which has been described clinically in the literature, is either localized or generalized inflammation of the oral mucosa in connection with a removable prosthesis. During this inflammatory process, the mycobacterial biofilm and the host’s immune response play an essential role. Among microorganisms of this mixed biofilm, the Candida species proliferates easily and changes from a commensal to an opportunistic pathogen. In this situation, the relationship between the Candida spp. and the host is influenced by the presence of the denture and conditioned both by the immune response and the oral microbiota. Specifically, this fungus is able to hijack the innate immune system of its host to cause infection. Additionally, older edentulous wearers of dentures may experience an imbalanced and decreased oral microbiome diversity. Under these conditions, the immune deficiency of these aging patients often promotes the spread of commensals and pathogens. The present narrative review aimed to analyze the innate and adaptive immune responses of patients with denture stomatitis and more particularly the involvement of Candida albicans sp. associated with this pathology.

Higher Number of EBI3 Cells in Mucosal Chronic Hyperplastic Candidiasis May Serve to Regulate IL-17-Producing Cells

Previous research into the inflammatory cell infiltrate of chronic hyperplastic candidosis (CHC) determined that the immune response is primarily composed of T cells, the majority of which are T helper (CD4⁺) cells. This present investigation used immunohistochemistry to further delineate the inflammatory cell infiltrate in CHC. Cells profiled were those expressing IL-17A cytokine, EBI3 and IL-12A subunits of the IL-35 cytokine, and FoxP3⁺ cells. Squamous cell papilloma (with Candida infection) and oral lichen planus tissues served as comparative controls to understand the local immune responses to Candida infection. The results demonstrated that Candida-induced inflammation and immune regulation co-exist in the oral mucosa of CHC and that high prevalence of cells expressing the EBI3 cytokine subunit may play an important role in this regulation. This balance between inflammation and immune tolerance toward invading Candida in the oral mucosa may be critical in determining progress of infection.

Mucosal IgA Prevents Commensal Candida albicans Dysbiosis in the Oral Cavity

The fungus Candida albicans colonizes the oral mucosal surface of 30–70% of healthy individuals. Due to local or systemic immunosuppression, this commensal fungus is able to proliferate resulting in oral disease, called oropharyngeal candidiasis (OPC). However, in healthy individuals C. albicans causes no harm. Unlike humans mice do not host C. albicans in their mycobiome. Thus, oral fungal challenge generates an acute immune response in a naive host. Therefore, we utilized C. albicans clinical isolates which are able to persist in the oral cavity without causing disease to analyze adaptive responses to oral fungal commensalism. We performed RNA sequencing to determine the transcriptional host response landscape during C. albicans colonization. Pathway analysis revealed an upregulation of adaptive host responses due to C. albicans oral persistence, including the upregulation of the immune network for IgA production. Fungal colonization increased cross-specific IgA levels in the saliva and the tongue, and IgA⁺ cells migrated to foci of fungal colonization. Binding of IgA prevented fungal epithelial adhesion and invasion resulting in a dampened proinflammatory epithelial response. Besides CD19⁺ CD138⁻ B cells, plasmablasts, and plasma cells were enriched in the tongue of mice colonized with C. albicans suggesting a potential role of B lymphocytes during oral fungal colonization. B cell deficiency increased the oral fungal load without causing severe OPC. Thus, in the oral cavity B lymphocytes contribute to control commensal C. albicans carriage by secreting IgA at foci of colonization thereby preventing fungal dysbiosis.

Histopathologic aspects of the so-called chronic hyperplastic candidiasis: An analysis of 36 cases

BACKGROUND

The present study aimed to analyze the histopathologic aspects of cases diagnosed as chronic hyperplastic candidiasis (CHC) in an oral pathology service, pointing out the most important features found.

METHODS

All cases histopathologically diagnosed as CHC between 2002 and 2018 were retrieved from the files of the service. Data of the patients and the lesions were collected. Histopathological analysis was performed to evaluate the microscopic characteristics and the amount of Candida present.

RESULTS

Thirty-six cases of CHC were retrieved. Women were more affected and there was a predilection for Whites. Most lesions appeared as a nodule or a white plaque, asymptomatic, on the tongue or buccal mucosa. Histopathologically, statistical significance was noted for the presence of epithelial hyperplasia, exocytosis, and mononuclear inflammatory infiltrate. Interestingly, only the association between dysplasia and the amount of fungus was noted.

CONCLUSIONS

CHC appears to be a distinct entity presenting typical histopathologic aspects. CHC might even show epithelial dysplasia. In those cases, the presence of a large amount of Candida together with other histopathological features should lead to the diagnosis of CHC and subsequent treatment. However, close follow up is important.

Immunohistochemical Expression Patterns of Inflammatory Cells Involved in Chronic Hyperplastic Candidosis

The profile of the inflammatory cell infiltrate in chronic hyperplastic candidosis (CHC) was determined in oral mucosal biopsies by immunohistochemistry. One tonsillar tissue section was included as an immunohistochemistry control, whilst squamous papilloma (n = 4) with secondary Candida infection was used as Candida controls. Oral lichen planus tissues (n = 10) provided negative controls for Candida presence, as well as positive controls for inflammation. Immunohistochemistry employed antibodies specific for CD3⁺ (T lymphocytes), CD4⁺ (T helper cells), CD8⁺ (cytotoxic T cells), and CD20⁺ (B lymphocytes). Manual counting of stained cells from digitised images determined the proportion of each cell type relative to the total number of cells, and these were assessed in the mucosa, the epithelium, and the lamina propria. The mean proportion of CD3⁺ cells was significantly higher than CD20⁺ cells in all tissue types. For CHC, the mean proportion of CD3⁺ cells in entire tissues was 15.6%, with the highest proportion in the lamina propria (32.6%) compared with the epithelium (3.9%). CD20⁺ cells were in much lower proportions (1.8%) in CHC, with the highest proportion (3.6%) in the lamina propria. T lymphocytes were predominately CD4⁺ cells (9.0%) compared with CD8⁺ cells (4.4%). CD4⁺ cells were most prevalent in the lamina propria (23.1%) compared with the epithelium (mean = 3.2%). From these results, it was concluded that the immune response invoked by Candida in CHC is primarily driven by the T helper cells.

Diagnosis and management of oral candidosis

Candida is a fungus (yeast) that is generally regarded as a normal and harmless member of the oral microbiome in humans. Should host defences against these commensals be compromised in any way then Candida can cause clinical signs and symptoms, which manifest as distinct forms of oral candidosis (candidiasis). Candida albicans is the most frequently isolated candidal species from the oral cavity, although a range of non-C. albicans Candida species are being increasingly encountered. The basic principle of the management of candidosis is to identify and eliminate any underlying host predisposing factor. However, in many cases, antifungal therapy will also be required as part of initial management. This article will provide an overview of the isolation, identification and pathogenicity of Candida species encountered within the mouth and relate these to clinical management of oral candidosis.

Immunology of oral candidiasis

A successful pathogen is one that is able to effectively survive and evade detection by the host immune defense. Oral candidiasis has adopted strategies, which evade host defense and eventually cause disease in at-risk patients. Host defense against infections with Candida spp. depends on rapid activation of an acute inflammatory response by innate immunity, followed by an incremental stimulation of specific immune responses mediated by T-cells (cellular immunity) or B-cells (humoral immunity). Understanding these complex pathways of immune evasion can potentially contribute to the development of novel therapeutic strategies against oral candidiasis.

Characterization of Candida albicans infection of an in vitro oral epithelial model using confocal laser scanning microscopy

INTRODUCTION

Oral candidosis presents as several distinct forms and one of these, chronic hyperplastic candidosis, is distinguished by penetration of the epithelium by Candida. The aim of this study was to use confocal laser scanning microscopy to examine invasion of the oral epithelium by Candida albicans from different oral conditions and to determine whether inherent strain differences exist that could relate to infection type. Reverse transcription-polymerase chain reaction was also used to detect products from virulence gene families.

METHODS

C. albicans (n = 19) was used to infect reconstituted human oral epithelium, which was incubated for 12 h. One half of the reconstituted human oral epithelium was then fixed and stained with concanavalin A-Alexa 594, pan-cytokeratin antibody-Alexa 488 and Hoechst nucleic acid dye. RNA was extracted from the remaining tissue for reverse transcription-polymerase chain reaction targeting secreted aspartyl proteinase, phospholipase and agglutinin-like sequence genes of C. albicans.

RESULTS

Confocal laser scanning microscopy revealed strain-dependent tissue invasion, with differences evident in surface colonization, C. albicans morphology and the extent and pattern of tissue penetration. Hyphae were seen to directly penetrate epithelial cells and migrate between keratinocytes with yeast budding also evident in the reconstituted human oral epithelium. A relationship between 'high tissue invasion' and expression of secreted aspartyl proteinase genes 4-6 was noted. Interestingly, four of the five 'high invaders' originated from chronic hyperplastic candidosis.

CONCLUSIONS

Confocal laser scanning microscopy permitted high resolution analysis of reconstituted human oral epithelium invasion by C. albicans and identified strain differences in the invasion process. Association between extensive hyphal morphology, direct epithelial penetration and high surface colonization were made with the 'highly invasive' strains.

Relationship between Candida infection and immune cellular response in inflammatory hyperplasia

OBJECTIVES

To analyze and quantify the CD8(+) and CD4(+) T-lymphocyte populations in inflammatory hyperplasia and to establish the relationship between the frequency and location of these cells and Candida infection.

METHODS

Samples of inflammatory hyperplasia were stained with PAS for evidence of Candida sp. and were classified in two groups, infected and control, according to the presence or absence of infection. After immunoreaction with specific anti-CD4 and anti-CD8 monoclonal antibodies, the distribution and frequency of the positive cells were analyzed in 41 cases (19 controls without Candida sp. and 22 infected cases). Lymphocytes were quantified in the three consecutive fields where the inflammatory infiltration was concentrated.

RESULTS

There was no relationship between the frequency and location of CD4(+) T cells and Candida sp. infection. The number of CD8(+) cells close to the fungi hyphae as well as the total number of CD8(+) T cells present in inflammatory hyperplasia were higher in the Candida sp. group than in the control noninfected group (P < 0.05).

CONCLUSION

Since the CD8(+) T cells were distributed according to the location of Candida sp. hyphae, and since a higher CD8(+)/total lymphocytes ratio was observed in the infected group, we suggest a role for CD8(+) T cells in the defense against Candida in oral infections associated with inflammatory hyperplasia in immunocompetent individuals.

In vitro inhibitory effect of Streblus asper leaf-extract on adhesion of Candida albicans to human buccal epithelial cells

This in vitro study aimed at determining the effects of a sublethal concentration of Streblus asper Lour (Moraceae) leaf ethanolic extract on adherence of Candida albicans to human buccal epithelial cells (HBEC). The minimum concentration of Streblus asper leaf ethanolic extract (SAE) that significantly reduced adherence (P<0.05) after a 1-h exposure was 15.6 mg/ml. However, there was a significant reduction (P<0.05) of candidal adhesion to HBEC after 1-min exposure to 125 mg/ml of SAE. Pre-treatment of either Candida or HBEC, or both, with 125 mg/ml of SAE for 1h resulted in reduced adherence. SAE at concentrations of 125 and 250 mg/ml also showed 41 and 61% inhibition of germ tube formation, respectively, which might affect adherence. These findings indicate that the sublethal concentration of SAE may modulate candidal colonization of the oral mucosa thereby suppressing the invasive potential of the pathogen.

Oral opportunistic infections in HIV-positive individuals: review and role of mucosal immunity

Oral opportunistic infections in the HIV-positive individual have been documented since the first reports of the epidemic, with many lesions associated with reduced CD4(+) T lymphocyte cell count. The most common oral lesions seen in HIV disease prior to the advent of highly active antiretroviral therapy (HAART) were oropharyngeal candidiasis and oral hairy leukoplakia. However, since the advent of HAART while many oral lesions have decreased significantly the incidence of oral warts has surprisingly increased. Despite the correlation of diminished CD4(+) T lymphocyte count to the occurrence of these lesions, it is rare for the lesions to occur concurrently suggesting that each pathologic lesion type is associated with distinct host immune dysfunctions. To date, the oral opportunistic infection most frequently investigated is oropharyngeal candidiasis, where data suggests that both systemic and local immunity is important for protection against infection. In contrast, recent investigations into the host responses associated with oral hairy leukoplakia and oral warts show little to no evidence of systemic or mucosal immune responsiveness despite the presumed competence of several types of leukocytes other than CD4(+) T cells. Together these data are suggesting that susceptibility to oropharyngeal candidasis in HIV-positive persons is predominantly immune-based, whereas protection or susceptibility to oral hairy leukoplakia and oral warts may be more associated with factors other than mucosal immune function.

In vitro secreted aspartyl proteinase activity of Candida albicans isolated from oral diseases and healthy oral cavities

The in vitro secreted aspartyl proteinase (SAP) activity of Candida albicans isolated from a variety of oral conditions, including healthy oral cavities, was determined. SAP activity (units/10(6) cells/ml, +/-SD) was 0.28 +/- 0.33 for pseudomembranous candidosis isolates (n = 18), 0.35 +/- 0.46 for chronic erythematous candidosis isolates (n = 21) and 0.30 +/- 0.32 for chronic hyperplastic candidosis isolates (n = 50). SAP activity of 0.19 +/- 0.22 was recorded for isolates from squamous cell carcinoma (n = 18), 0.26 +/- 0.37 for burning mouth syndrome isolates (n = 29), 0.25 +/- 0.38 for isolates from xerostomia (n = 15) and 0.39 +/- 0.50 for isolates from lichen planus (n = 13). The SAP activity of isolates from oral disease states was significantly (P < 0.05) higher than that recorded for 28 isolates from healthy mouths (activity of 0.04 +/- 0.03). However, there was no significant difference in the SAP activity between the three forms of clinical oral candidosis (P > 0.05). SAP activity was inhibited in control samples containing the SAP inhibitor, pepstatin A. These results indicate that C. albicans strains associated with oral disease have inherently higher SAP activity.

Immunohistochemical evaluation of T cells in oral lesions from human immunodeficiency virus-positive persons with oropharyngeal candidiasis

Oropharyngeal candidiasis (OPC), caused by Candida albicans, is the most frequent opportunistic fungal infection in human immunodeficiency virus (HIV)-positive persons. Although Th1-type CD4(+) T cells are considered important for host defense against mucosal C. albicans infections, there is a paucity of information regarding the presence and/or role of T cells in OPC lesions. In pursuit of this, initial chromophore immunohistochemical studies showed a majority of CD8(+) rather than CD4(+) cells equally distributed throughout the buccal mucosa of OPC(-) persons (HIV(-) or HIV(+)), irrespective of blood CD4(+) cell numbers. In contrast, CD8(+) cells in lesions from HIV(+) OPC(+) persons were in significantly higher numbers and concentrated at the lamina propria-epithelium interface, a considerable distance from the Candida at the outer epithelium. Dual fluorescence and confocal microscopy confirmed that the majority of CD8(+), but not CD4(+), cells were T cells by the presence or absence, respectively, of CD3 on each cell type. These results suggest that CD8(+) T cells may be important for oral host defense against OPC, especially when CD4 cell numbers are reduced, with a potential CD8 cell-specific dysfunction associated with susceptibility to OPC.

Immunity to Candida

Candida species are commensal fungal organisms as well as opportunistic pathogens of mucosal tissues. From the commensal relationship, most healthy individuals have demonstrable Candida-specific immunity. In immunocompromised persons, however, fungal infections caused primarily by C. albicans often occur. In HIV disease, up to 90% of HIV+ persons will have a symptomatic episode of oropharyngeal candidiasis (OPC) sometime during progression to AIDS, many of which become recurrent. In contrast, vulvovaginal candidiasis (VVC) and systemic Candida infections (candidaemia) are much less common during HIV disease, indicating the diversity and compartmentalization of the host response to Candida. Both innate resistance and acquired immunity play some role in maintaining C. albicans in the commensal state and protecting the systemic circulation. Polymorphonuclear leukocytes (PMNL) are critical for protection against systemic infections, whereas cell-mediated immunity (CMI) by Th1-type CD4+ T-cells is important for protection against mucosal infections. However, there is a discordant role for CMI at the vaginal versus oral mucosa, whereas little to no role for local or systemic CMI is evident at the vaginal mucosa. In contrast, there is a strong correlation between reduced blood CD4+ cells and the incidence of OPC, but it remains unclear whether systemic or local CMI is more important. Evaluation of systemic CMI in a cohort of HIV+ individuals with and without mucosal candidiasis revealed that Candida-specific CMI is not different between HIV+ persons with OPC or VVC and HIV- persons. Thus, the correlation of reduced CD4+ cell numbers to OPC may be explained by the requirement for a threshold number of systemic CD4+ cells to protect the oral mucosa together with the status of local immunity. Indeed, HIV+ persons with and without OPC had a Th2-type salivary cytokine profile suggestive of susceptibility to Candida infection compared with a protective Th0/Th1-type profile in HIV- persons. Candida-specific antibodies, although present, are controversial relative to a role in protection or eradication of infection. While studies of mucosal innate resistance are limited, we recently found that epithelial cells from saliva and vaginal lavages of healthy individuals inhibit the growth of Candida in vitro. This epithelial cell anti-Candida activity requires cell contact by viable cells with no role for soluble factors, including saliva. Interestingly, oral epithelial cells from HIV+ persons with OPC had significantly reduced activity, indicating some protective role for the epithelial cells. Taken together, these data suggest that immunity to Candida is site-specific, compartmentalized and involves innate and/or acquired mechanisms from systemic and/or local sources.

[Evaluation of surface disinfectants utilized in dentistry]

Surface disinfection is a procedure carried out on the external parts of the dental equipment as well as on other items of the dental office. The aim of this study was to analyze the efficacy of 4 surface disinfectants utilized in dentistry: 77 degrees GL alcohol, phenolic compound (Duplofen), iodophor (PVP-I) and 77 degrees GL alcohol with 5% of chlorhexidine. Four surfaces of the equipment were analyzed in the study (the carter, the washbasin for hand-washing, the headrest of the chair and the external surface of the reflector), and the spray-wipe-spray procedure was carried out. From each surface, samples were collected by means of surface plates containing Mitis Salivarius bacitracin sucrose agar, Sabouraud Dextrose agar with chloramphenicol, MacConkey agar and blood agar, for counting mutans streptococci, Candida yeasts, gram-negative bacteria and total microorganisms, respectively (ufc/plate). The results were statistically analyzed by means of the Student's t test in order to compare the mean ufc/plate values. The most effective disinfectant was 77 degrees GL alcohol with 5% of chlorhexidine, mainly against gram-positive bacteria. Iodophor and phenolic compound were also effective in microbial reduction. 77 degrees GL alcohol was the least effective product - however, although it is not considered as a surface disinfectant, it produced, in this study, statistically significant microbial reduction after the disinfecting procedure.

Pathology and clinical correlates in oral candidiasis and its variants: a review

Although Candida albicans is well recognised as the major agent of oral candidiasis, it is not clear why several variants such as pseudomembranous (PC), erythematous (EC) and hyperplastic candidiasis (HC) manifest in different individuals, sometimes singly and on other occasions, in combination. The present review focuses on recent histopathologic and immunocytochemical studies as well as the pathogenic attributes of the yeast, in an attempt to address the following queries. (1) Do histopathologic studies of the different variants of candidiasis in immunocompetent and immunocompromised individuals help explain these varying manifestations? (2) Under what circumstances does oral candidiasis manifest as a pseudomembranous rather than an erythematous lesion or vice versa? (3) Are there differences in immunoreactivity in closely adjacent mucosae so that the variable presentation of such lesions reflect differences in the local mucosal immune system? Recent studies of PC, EC and HC offer some insights into the pathogenic mechanisms involved. Histopathologic and immunohistochemical finding in cases of PC and EC in HIV-infected patients and controls appear to be comparable, with a marked reduction or even an absence of CD4+ cells. The latter phenomenon is marked in PC compared with the EC, and explicable in terms of a breakdown of the local immune response in the former, and a hypersensitivity reaction against Candida antigens in the latter. Hyperplastic candidiasis on the other hand could be considered a superficial cellular reaction against the pathogen, which cannot entirely be eradicated by the systemic or local host immune response. The virulent attributes of the fungus, such as the production of extracellular proteinases, do significantly differ within and between species and thereby play a contributory role in the genesis of the clinical variants. Although the available data do give a tantalising glimpse of the contributory mechanisms for the aetiopathology of PC, EC and HC, further research is warranted to elucidate response of the host to this ubiquitous fungal pathogen.

Unique inflammatory features noted in intraorally transferred skin flaps: correlation with Candida albicans infection

OBJECTIVE

The purpose of this study was to evaluate how well intraorally transferred skin flaps endure their new surroundings.

STUDY DESIGN

Biopsy specimens were taken from 20 patients who had undergone microsurgical reconstruction and as pretransferred skin from 5 of these patients at the time of surgery. The study used immunohistochemistry for immunocompetent cells, differentiation markers for the epidermis and desmosomal proteins, and immunoelectron microscopy for desmosomal protein, in addition to routine histologic examination, including Sudan IV, periodic acid Schiff, and Grocott stains. We also measured the thickness of the epidermis and stratum corneum. Oral swabs from the skin flaps were examined for the presence of yeasts, particularly Candida albicans, by means of a culture method.

RESULTS

According to the results of periodic acid-Schiff and Grocott staining, 20 cases were divided into 2 groups: fungal element-positive cases (n = 15) and fungal element-negative cases (n = 5). All swabs from the former were positive for Candida albicans. In these fungus-positive cases, histopathologic evaluation revealed marked diminution of stratum corneum and pronounced epidermal hyperplasia. Immunohistochemistry demonstrated the dermal infiltration of numerous immunocompetent cells-CD4+, CD8+, CD20+, CD68+, neutrophil elastase+, and HLA-DR+ cells-and the scarce infiltration of IgA+ and IgG+ cells. There were scattered CD1a+, CD4+, CD8+, and HLA-DR+ cells and elastase+ neutrophils in the epidermis. Expression of cytokeratin subtypes (10, 14, 16, and 19), involucrin, and tenascin showed the characteristic features of epidermal proliferation. Enumeration of Ki-67+ keratinocytes showed an increase, indicating epidermal proliferation. Expression of desmoglein 1 and desmocollin 1 in the epidermal keratinocytes was decreased in comparison with that in the pretransferred skin. Immunoelectron microscopy for desmoglein 1 confirmed the reduced immunoreactive deposits along the desmosomal plaques. In the fungus-negative cases, all such changes were a great deal milder.

CONCLUSIONS

Taken together, our results demonstrate that most intraorally transferred flaps are affected by an inflammatory process that is induced by the influence of the wet oral environment. They present psoriasiform tissue reactions characterized by epidermal hyperproliferation that are mostly due to Candida albicans infection.

Oral keratinocyte immune responses in HIV-associated candidiasis

INTRODUCTION

Candidiasis is the most commonly encountered opportunistic infection among HIV-positive subjects. The purpose of this study was to assess specific keratinocyte immune parameters in the pseudomembranous and erythematous forms of HIV-associated oral candidiasis.

MATERIAL/METHODS

This collaborative study from three centers analyzed 25 HIV-positive and 10 HIV-negative subjects with either pseudomembranous or erythematous candidiasis. Oral biopsy specimens from lesional tissues were procured, and histopathologic features were correlated with immunohistochemical and in situ hybridization investigations for the expression of interleukin 1 alpha, interleukin 8, antimicrobial calprotectin, lymphocyte populations, and Candida antigen.

RESULTS

Both pseudomembranous and erythematous candidiasis among HIV-infected subjects showed a mild interface lymphocytic mucositis with the presence of neutrophilic subcorneal abscesses in the latter. Erythematous candidiasis cases that failed to show surface mycelia, did yield positive results for Candida antigens in the parakeratinized layer. The expression of inflammatory chemokines were positive in all groups and calprotectin appeared to serve as a keratinocyte barrier to hyphal penetration.

CONCLUSIONS

The erythematous form of candidiasis is often devoid of hyphae yet the presence of Candida antigens in the surface epithelium implicates an immune or allergic process. The intactness of chemokines and antimicrobial calprotectin in keratinocytes may explain why disseminated candidiasis is rarely encountered in HIV-infected patients.