Bimekizumab in psoriasis: a monocentric study evaluating short- and mid-term effectiveness and safety profile in a real-world setting

INTRODUCTION

Bimekizumab is a humanized monoclonal IgG1 antibody with a unique mechanism of action, as it inhibits both IL17A and IL17F molecules. This dual inhibition is thought to be responsible for its high efficacy in treating chronic plaque psoriasis with rapid onset of action in Randomized Controlled Trials (RCTs). Concerning safety, oral candidiasis was one of the most common drug-related adverse events, commonly mild-to-moderate in severity. Although data from RCTs supporting this efficacy and safety profile of bimekizumab is numerous, results from the real-world setting concerning short- and mid-term treatment effectiveness and safety profile are limited.

MATERIALS AND METHODS

An observational, retrospective, monocentric study was conducted at the Psoriasis Outpatient Unit of "A. Sygros" Hospital for Skin and Venereal Diseases, in Athens, Greece, which included 61 adult patients with moderate-to-severe skin psoriasis, who received at least one dosage of bimekizumab.

RESULTS

At week 4, 65.7% achieved PASI75, 45.7% PASI90, and 32.4% PASI100. After 16 weeks of treatment, 92.3/76.9/66.7% of the patients achieved PASI75/90/100, respectively. Increased BMI, previous treatment with another IL-17 inhibitor, or previous exposure to another biologic did not seem to influence the possibility of achieving PASI90 and PASI100 at week 16 of bimekizumab treatment in this cohort. Six (9.8%) cases of possibly drug-related AEs were reported, from which four incidences of oral candidiasis.

CONCLUSION

Our results confirm that this IL17A/F inhibitor is highly effective, with a tolerability profile similar to the one expected from RCTs.

Expression Profiles of GILZ and Annexin A1 in Human Oral Candidiasis and Lichen Planus

Adrenal glands are the major source of glucocorticoids, but recent studies indicate tissue-specific production of cortisol, including that in the oral mucosa. Both endogenous and exogenous glucocorticoids regulate the production of several proteins, including the glucocorticoid-induced leucine zipper (GILZ) and Annexin A1, which play important roles in the regulation of immune and inflammatory responses. Common inflammation-associated oral conditions include lichen planus and candidiasis, but the status of GILZ and Annexin A1 in these human conditions remains to be established. Accordingly, archived paraffin-embedded biopsy samples were subjected to immunohistochemistry to establish tissue localization and profile of GILZ and Annexin A1 coupled with the use of hematoxylin–eosin stain for histopathological assessment; for comparison, fibroma specimens served as controls. Histopathological examination confirmed the presence of spores and pseudohyphae for oral candidiasis (OC) specimens and marked inflammatory cell infiltrates for both OC and oral lichen planus (OLP) specimens compared to control specimens. All specimens displayed consistent and prominent nuclear staining for GILZ throughout the full thickness of the epithelium and, to varying extent, for inflammatory infiltrates and stromal cells. On the other hand, a heterogeneous pattern of nuclear, cytoplasmic, and cell membrane staining was observed for Annexin A1 for all specimens in the suprabasal layers of epithelium and, to varying extent, for inflammatory and stromal cells. Semi-quantitative analyses indicated generally similar fractional areas of staining for both GILZ and Annexin A1 among the groups, but normalized staining for GILZ, but not Annexin A1, was reduced for OC and OLP compared to the control specimens. Thus, while the cellular expression pattern of GILZ and Annexin A1 does not differentiate among these conditions, differential cellular profiles for GILZ vs. Annexin A1 are suggestive of their distinct physiological functions in the oral mucosa.

Mucosal Bacteria Modulate Candida albicans Virulence in Oropharyngeal Candidiasis

Oropharyngeal candidiasis (OPC) is the most prevalent oral infection in immunocompromised patients, primarily associated with Candida albicans. Increasing evidence points to a significant role of mucosal bacteria on the transition of C. albicans from commensal to pathogenic. In this work, we hypothesized that changes in the abundance or composition of the mucosal bacterial microbiota induced by dietary sucrose during the development of OPC can modulate C. albicans virulence. C. albicans burdens and mucosal lesions were evaluated in a mouse cortisone immunosuppression model amended with sucrose. We also analyzed the mucosal bacterial composition using 16S rRNA gene sequencing and culture methods. In immunocompetent mice, sucrose significantly increased total bacterial burdens and reduced alpha diversity, by increasing the relative abundance of mitis group streptococci. In immunocompromised mice, C. albicans infection was associated with a significantly reduced bacterial alpha diversity due to an increase in the relative abundance of enterococci. When exposed to dietary sucrose, these mice had reduced C. albicans burdens and reduced bacterial alpha diversity, associated with an increase in the relative abundance of Lactobacillus. SparCC correlation networks showed a significant negative correlation between Lactobacillus and Enterococcus in all Candida-infected mice. Depletion of lactobacilli with antibiotic treatment partially restored C. albicans burdens in mice receiving sucrose. In coculture in vitro experiments, mouse oral Lactobacillus johnsonii isolates inhibited growth of Enterococcus faecalis isolates and C. albicans. These results support the hypothesis that the sucrose-induced attenuation of C. albicans virulence was a result of changes in the mucosal bacterial microbiome characterized by a reduction in enterococci and an increase in lactobacilli. IMPORTANCE By comparing Candida albicans virulence and the mucosal bacterial composition in a mouse oral infection model, we were able to dissect the effects of the host environment (immunosuppression), infection with C. albicans, and local modulating factors (availability of sucrose as a carbon source) on the mucosal bacterial microbiome and its role on fungal virulence. We showed that changes in endogenous microbial communities in response to sucrose can lead to attenuation of fungal disease. We also showed that Lactobacillus johnsonii may curtail Candida virulence both by inhibiting its growth and by inhibiting the growth of potentially synergistic bacteria such as enterococci. Our results support the concept that Candida pathogenesis should be viewed in the contexts of both a susceptible host and a mucosal bacterial microbiota conducive to virulence.

Oral epithelial IL-22/STAT3 signaling licenses IL-17-mediated immunity to oral mucosal candidiasis

Oropharyngeal candidiasis (OPC; thrush) is an opportunistic infection caused by the commensal fungus Candida albicans Interleukin-17 (IL-17) and IL-22 are cytokines produced by type 17 lymphocytes. Both cytokines mediate antifungal immunity yet activate quite distinct downstream signaling pathways. While much is now understood about how IL-17 promotes immunity in OPC, the activities of IL-22 are far less well delineated. We show that, despite having similar requirements for induction from type 17 cells, IL-22 and IL-17 function nonredundantly during OPC. We find that the IL-22 and IL-17 receptors are required in anatomically distinct locations within the oral mucosa; loss of IL-22RA1 or signal transducer and activator of transcription 3 (STAT3) in the oral basal epithelial layer (BEL) causes susceptibility to OPC, whereas IL-17RA is needed in the suprabasal epithelial layer (SEL). Transcriptional profiling of the tongue linked IL-22/STAT3 not only to oral epithelial cell proliferation and survival but also, unexpectedly, to driving an IL-17-specific gene signature. We show that IL-22 mediates regenerative signals on the BEL that replenish the IL-17RA-expressing SEL, thereby restoring the ability of the oral epithelium to respond to IL-17 and thus to mediate antifungal events. Consequently, IL-22 signaling in BEL "licenses" IL-17 signaling in the oral mucosa, revealing spatially distinct yet cooperative activities of IL-22 and IL-17 in oral candidiasis.

Langerin+ DCs regulate innate IL-17 production in the oral mucosa during Candida albicans-mediated infection

The opportunistic fungal pathogen Candida albicans frequently causes diseases such as oropharyngeal candidiasis (OPC) in immunocompromised individuals. Although it is well appreciated that the cytokine IL-17 is crucial for protective immunity against OPC, the cellular source and the regulation of this cytokine during infection are still a matter of debate. Here, we directly visualized IL-17 production in the tongue of experimentally infected mice, thereby demonstrating that this key cytokine is expressed by three complementary subsets of CD90+ leukocytes: RAG-dependent αβ and γδ T cells, as well as RAG-independent ILCs. To determine the regulation of IL-17 production at the onset of OPC, we investigated in detail the myeloid compartment of the tongue and found a heterogeneous and dynamic mononuclear phagocyte (MNP) network in the infected tongue that consists of Zbtb46-Langerin- macrophages, Zbtb46+Langerin+ dendritic cells (DCs) and Ly6C+ inflammatory monocytes. Of those, the Langerin+ DC population stands out by its unique capacity to co-produce the cytokines IL-1β, IL-6 and IL-23, all of which promote IL-17 induction in response to C. albicans in the oral mucosa. The critical role of Langerin+ DCs for the innate IL-17 response was confirmed by depletion of this cellular subset in vivo, which compromised IL-17 induction during OPC. In conclusion, our work revealed key regulatory factors and their cellular sources of innate IL-17-dependent antifungal immunity in the oral mucosa.

IL-22 neutralizing autoantibodies impair fungal clearance in murine oropharyngeal candidiasis model

Protection against mucocutaneous candidiasis depends on the T helper (Th)17 pathway, as gene defects affecting its integrity result in inability to clear Candida albicans infection on body surfaces. Moreover, autoantibodies neutralizing Th17 cytokines have been related to chronic candidiasis in a rare inherited disorder called autoimmune polyendocriopathy candidiasis ectodermal dystrophy (APECED) caused by mutations in autoimmune regulator (AIRE) gene. However, the direct pathogenicity of these autoantibodies has not yet been addressed. Here we show that the level of anti-IL17A autoantibodies that develop in aged Aire-deficient mice is not sufficient for conferring susceptibility to oropharyngeal candidiasis. However, patient-derived monoclonal antibodies that cross-react with murine IL-22 increase the fungal burden on C. albicans infected mucosa. Nevertheless, the lack of macroscopically evident infectious pathology on the oral mucosa of infected mice suggests that additional susceptibility factors are needed to precipitate a clinical disease.

(B3) Markers of Immunodeficiency and Mechanisms of HAART Therapy on Oral Lesions

Highly active anti-retroviral therapy (HAART) has revolutionized the treatment and prognosis of HIV disease and AIDS in those who can take advantage of the treatment. There are currently 20 different anti-retroviral drugs in 4 different classes that are used in specific combinations. Suppression of HIV replication and immune reconstitution are goals of therapy. Since the prevalence of some easily detectable oral manifestations of HIV/AIDS (OMHIV/AIDS) decreases with HAART, it has been suggested that they might be clinically useful surrogate markers of HAART efficacy and immune status. This might be particularly useful if their recurrence presaged or accompanied HAART failure. To date, there has been little work in this area, but its potential value to the clinical management of HIV/AIDS is apparent, especially if frequent measures of viral load and CD4 cell counts are not readily available. However, the usefulness of OMHIV/AIDS as signals for HAART failure is complicated by three phenomena: the immune reconstitution syndrome, the similarity of some adverse reactions of HAART to OMHIV/AIDS, and the direct inhibitory effect of HAART medications on some OMHIV/AIDS ( e.g., inhibition of oral candidosis by protease inhibitors). This workshop considered the current evidence and proposed pertinent research questions.

Antibody blockade of IL-17 family cytokines in immunity to acute murine oral mucosal candidiasis

Antibodies targeting IL-17A or its receptor, IL-17RA, are approved to treat psoriasis and are being evaluated for other autoimmune conditions. Conversely, IL-17 signaling is critical for immunity to opportunistic mucosal infections caused by the commensal fungus Candida albicans, as mice and humans lacking the IL-17R experience chronic mucosal candidiasis. IL-17A, IL-17F, and IL-17AF bind the IL-17RA-IL-17RC heterodimeric complex and deliver qualitatively similar signals through the adaptor Act1. Here, we used a mouse model of acute oropharyngeal candidiasis to assess the impact of blocking IL-17 family cytokines compared with specific IL-17 cytokine gene knockout mice. Anti-IL-17A antibodies, which neutralize IL-17A and IL-17AF, caused elevated oral fungal loads, whereas anti-IL-17AF and anti-IL-17F antibodies did not. Notably, there was a cooperative effect of blocking IL-17A, IL-17AF, and IL-17F together. Termination of anti-IL-17A treatment was associated with rapid C. albicans clearance. IL-17F-deficient mice were fully resistant to oropharyngeal candidiasis, consistent with antibody blockade. However, IL-17A-deficient mice had lower fungal burdens than anti-IL-17A-treated mice. Act1-deficient mice were much more susceptible to oropharyngeal candidiasis than anti-IL-17A antibody-treated mice, yet anti-IL-17A and anti-IL-17RA treatment caused equivalent susceptibilities. Based on microarray analyses of the oral mucosa during infection, only a limited number of genes were associated with oropharyngeal candidiasis susceptibility. In sum, we conclude that IL-17A is the main cytokine mediator of immunity in murine oropharyngeal candidiasis, but a cooperative relationship among IL-17A, IL-17AF, and IL-17F exists in vivo. Susceptibility displays the following hierarchy: IL-17RA- or Act1-deficiency > anti-IL-17A + anti-IL-17F antibodies > anti-IL-17A or anti-IL-17RA antibodies > IL-17A deficiency.

Antigen-Specific Th17 Cells Are Primed by Distinct and Complementary Dendritic Cell Subsets in Oropharyngeal Candidiasis

Candida spp. can cause severe and chronic mucocutaneous and systemic infections in immunocompromised individuals. Protection from mucocutaneous candidiasis depends on T helper cells, in particular those secreting IL-17. The events regulating T cell activation and differentiation toward effector fates in response to fungal invasion in different tissues are poorly understood. Here we generated a Candida-specific TCR transgenic mouse reactive to a novel endogenous antigen that is conserved in multiple distant species of Candida, including the clinically highly relevant C. albicans and C. glabrata. Using TCR transgenic T cells in combination with an experimental model of oropharyngeal candidiasis (OPC) we investigated antigen presentation and Th17 priming by different subsets of dendritic cells (DCs) present in the infected oral mucosa. Candida-derived endogenous antigen accesses the draining lymph nodes and is directly presented by migratory DCs. Tissue-resident Flt3L-dependent DCs and CCR2-dependent monocyte-derived DCs collaborate in antigen presentation and T cell priming during OPC. In contrast, Langerhans cells, which are also present in the oral mucosa and have been shown to prime Th17 cells in the skin, are not required for induction of the Candida-specific T cell response upon oral challenge. This highlights the functional compartmentalization of specific DC subsets in different tissues. These data provide important new insights to our understanding of tissue-specific antifungal immunity.

Candida spp. are present in the normal microbiota without causing damage to the host. They can become pathogenic and bear a serious health hazard for individuals with a weakened immune system. The continuous incidence of fungal infections and the increase in resistance against available antifungal drugs urge the development of novel preventive and therapeutic strategies. Knowledge gained from understanding how immunocompetent mammals control Candida will help develop new immunotherapeutic and-prophylactic approaches suitable to improve patient prognosis. It is well known that T helper cells, and in particular the Th17 subset, provide resistance against mucocutaneous infections with Candida. However, the mechanisms through which T cell-mediated antifungal immunity is induced in such context are not well understood. Here we developed a new experimental system to study the regulation of antigen-specific T cells with high resolution. Our results reveal the interplay of different dendritic cell subsets associated to the oral mucosa of infected mice that directly present fungal antigen to Candida-specific T cells and orchestrate a protective Th17 response in a tissue specific manner. Thus, our data highlight important features of immune regulation in the oral mucosa, a tissue that is immunologically not well characterized.

C/EBPβ Promotes Immunity to Oral Candidiasis through Regulation of β-Defensins

Humans or mice subjected to immunosuppression, such as corticosteroids or anti-cytokine biologic therapies, are susceptible to mucosal infections by the commensal fungus Candida albicans. Recently it has become evident that the Th17/IL-17 axis is essential for immunity to candidiasis, but the downstream events that control immunity to this fungus are poorly understood. The CCAAT/Enhancer Binding Protein-β (C/EBPβ) transcription factor is important for signaling by multiple inflammatory stimuli, including IL-17. C/EBPβ is regulated in a variety of ways by IL-17, and controls several downstream IL-17 target genes. However, the role of C/EBPβ in vivo is poorly understood, in part because C/EBPβ-deficient mice are challenging to breed and work with. In this study, we sought to understand the role of C/EBPβ in the context of an IL-17-dependent immune response, using C. albicans infection as a model system. Confirming prior findings, we found that C/EBPβ is required for immunity to systemic candidiasis. In contrast, C/EBPβ(-/-) mice were resistant to oropharyngeal candidiasis (OPC), in a manner indistinguishable from immunocompetent WT mice. However, C/EBPβ(-/-) mice experienced more severe OPC than WT mice in the context of cortisone-induced immunosuppression. Expression of the antimicrobial peptide β-defensin (BD)-3 correlated strongly with susceptibility in C/EBPβ(-/-) mice, but no other IL-17-dependent genes were associated with susceptibility. Therefore, C/EBPβ contributes to immunity to mucosal candidiasis during cortisone immunosuppression in a manner linked to β-defensin 3 expression, but is apparently dispensable for the IL-17-dependent response.

Simple markers for the detection of severe immunosuppression in children with HIV infection in highly resource-scarce settings: experience from the Democratic Republic of Congo

OBJECTIVES

The decision to initiate the antiretroviral therapy in HIV-infected children living in poor countries is compromised by lack of resources. The objective of this study is to identify simple clinical and biological markers other than CD4+ count and viral load measurement that could help the decision to introduce antiretroviral treatment and to monitor patients.

METHODS

A cross sectional study was conducted between January and March 2005 in Kinshasa, Democratic Republic of Congo.

RESULTS

Eighty-four children infected with HIV were recruited. In this cohort, the lymphocytes (P = 0.001) and CD4 (P = 0.0001) were significantly lower in children with immunological stage 3 and viral load (P = 0.027) was significantly higher in children at the same immunological stage. Reticulocytes (r = +0.440), white blood cells count (r = +0.560), total lymphocytes (r = +0.675) and albumin (r = +0.381) showed positive significant correlations with CD4. Haemoglobin (r = - 0.372), Haematocrit (r = - 0.248), red blood cells (r = - 0.278) and CD4 (r = - 0.285) showed negative significant correlations with viral load. Neutropaenia (P = 0.02), enlarged nodes (P = 0.005) and oral candidiasis (P = 0.04) were associated with viral load >10,000 copies/ml. Oral candidiasis (P = 0.02) was associated with CD4 level < 15%.

CONCLUSION

Oral candidiasis, enlarged nodes, total lymphocytes count, neutropaenia and albumin predict severe immunodepression. These clinical and biological markers may guide the clinician in making the decision to initiate antiretroviral therapy in highly resource-scarce settings.

Signaling through IL-17C/IL-17RE is dispensable for immunity to systemic, oral and cutaneous candidiasis

Candida albicans is a commensal fungal microbe of the human orogastrointestinal tract and skin. C. albicans causes multiple forms of disease in immunocompromised patients, including oral, vaginal, dermal and disseminated candidiasis. The cytokine IL-17 (IL-17A) and its receptor subunits, IL-17RA and IL-17RC, are required for protection to most forms of candidiasis. The importance of the IL-17R pathway has been observed not only in knockout mouse models, but also in humans with rare genetic mutations that impact generation of Th17 cells or the IL-17 signaling pathway, including Hyper-IgE Syndrome (STAT3 or TYK2 mutations) or IL17RA or ACT1 gene deficiency. The IL-17 family of cytokines is a distinct subclass of cytokines with unique structural and signaling properties. IL-17A is the best-characterized member of the IL-17 family to date, but far less is known about other IL-17-related cytokines. In this study, we sought to determine the role of a related IL-17 cytokine, IL-17C, in protection against oral, dermal and disseminated forms of C. albicans infection. IL-17C signals through a heterodimeric receptor composed of the IL-17RA and IL-17RE subunits. We observed that IL-17C mRNA was induced following oral C. albicans infection. However, mice lacking IL-17C or IL-17RE cleared C. albicans infections in the oral mucosa, skin and bloodstream at rates similar to WT littermate controls. Moreover, these mice demonstrated similar gene transcription profiles and recovery kinetics as WT animals. These findings indicate that IL-17C and IL-17RE are dispensable for immunity to the forms of candidiasis evaluated, and illustrate a surprisingly limited specificity of the IL-17 family of cytokines with respect to systemic, oral and cutaneous Candida infections.

Th17 inflammation model of oropharyngeal candidiasis in immunodeficient mice

Oropharyngeal Candidiasis (OPC) disease is caused not only due to the lack of host immune resistance, but also the absence of appropriate regulation of infection-induced immunopathology. Although Th17 cells are implicated in antifungal defense, their role in immunopathology is unclear. This study presents a method for establishing oral Th17 immunopathology associated with oral candidal infection in immunodeficient mice. The method is based on reconstituting lymphopenic mice with in vitro cultured Th17 cells, followed by oral infection with Candida albicans (C. albicans). Results show that unrestrained Th17 cells result in inflammation and pathology, and is associated with several measurable read-outs including weight loss, pro-inflammatory cytokine production, tongue histopathology and mortality, showing that this model may be valuable in studying OPC immunopathology. Adoptive transfer of regulatory cells (Tregs) controls and reduces the inflammatory response, showing that this model can be used to test new strategies to counteract oral inflammation. This model may also be applicable in studying oral Th17 immunopathology in general in the context of other oral diseases.

Association between oral candidiasis and low CD4+ count among HIV positive patients in Hoima Regional Referral Hospital

BACKGROUND

The aim of this study was to determine the prevalence of Human Immune Virus (HIV) related oral lesions and their association with Cluster of Differentiation 4 (CD4+) count among treatment naïve HIV positive patients.

METHODS

This was a descriptive and analytical cross sectional study. Participants were 346 treatment naïve HIV positive adult patients. These were consecutively recruited from Hoima Regional Referral hospital between March and April 2012. Data collection involved interviews, oral examinations and laboratory analysis.

RESULTS

A total of 168(48.6%) participants had oral lesions. The four commonest lesions were oral candidiasis (24.9%, CI = 20.6-29.7%), melanotic hyperpigmentation (17.3%, CI = 13.7-21.7%), kaposi sarcoma (9.3%, CI = 6.6-12.8%) and Oral Hairy Leukoplakia (OHL) (5.5%, CI = 3.5-8.4%). There was significant association between oral candidiasis and immunosuppression measured as CD4+ less than 350 cells/mm3 (OR = 2.69, CI = 1.608-4.502, p < 0.001). Oral candidiasis was the only oral lesion significantly predictive of immunosuppression (OR = 2.56, CI = 1.52-4.30, p < 0.001) with a Positive Predictive Value (PPV) of 48.2%, Negative Predictive Value (NPV) of 74.3%, 38.1% sensitivity and specificity of 81.4%.

CONCLUSION

Oral candidiasis can be considered as a marker for immunesuppression, making routine oral examinations essential in the management of HIV positive patients.

Frequency, pattern, and extent of skin diseases in relation to CD4+ cell count among adults with human immunodeficiency virus infection or acquired immunodeficiency syndrome in Osogbo, southwestern Nigeria

BACKGROUND

Skin diseases characterize all stages of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) and contribute significantly to associated morbidity and mortality.

OBJECTIVES

The aim of this study was to document the prevalences, patterns, and extents (severity) of skin diseases and their relationships with immunologic status in HIV/AIDS patients.

METHODS

A total of 140 HIV/AIDS patients in different stages of HIV infection and 140 controls were recruited. Skin diseases were documented and CD4+ cell counts determined in all subjects. Severity was assessed according to the body surface area affected (using the Wallace rule of nines and the rule of palm) for lesions that tended to be widespread. The number of digits involved was counted for lesions involving the nails. Intensity of pain was graded for specific conditions such as herpes zoster. Chi-squared statistics and Pearson correlations were determined.

RESULTS

Mean±standard deviation age was 35.04±8.83 years in the patient group and 32.21±8.30 years in the control group. The prevalences and patterns of skin diseases in HIV/AIDS patients were similar to those reported in previous studies. Most commonly found dermatoses were oral candidiasis (n=28, 20.0%), pruritic papular eruption (n=27, 19.3%), xeroderma (n=23, 16.4%), dermatophytosis (n=22, 15.7%), and fluffy hair (n=19, 13.6%). The presence of specific skin lesions represented a better correlate with immunosuppression than cutaneous extents. However, the extents of viral warts and multiple blue–black nails correlated significantly with CD4+ cell count. The presence of a lighter hair color phenotype signifies a lower CD4+ cell count than a softer hair phenotype.

CONCLUSIONS

The presence of specific skin lesions correlates more strongly with a low CD4+ cell count than does the extent of their distribution, except in cases of viral warts. The presence of and higher numbers of nails affected with blue–black nail hyperpigmentation suggest severe immunosuppression.

Defective IL-17- and IL-22-dependent mucosal host response to Candida albicans determines susceptibility to oral candidiasis in mice expressing the HIV-1 transgene

BACKGROUND

The tissue-signaling cytokines IL-17 and IL-22 are critical to host defense against oral Candida albicans infection, by their induction of oral antimicrobial peptide expression and recruitment of neutrophils. Mucosal Th17 cells which produce these cytokines are preferentially depleted in HIV-infected patients. Here, we tested the hypothesis that defective IL-17- and IL-22-dependent host responses to C. albicans determine the phenotype of susceptibility to oropharyngeal candidiasis (OPC) in transgenic (Tg) mice expressing HIV-1.

RESULTS

Naïve CD4+ T-cells and the differentiated Th1, Th2, Th17, Th1Th17 and Treg lineages were all profoundly depleted in cervical lymph nodes (CLNs) of these Tg mice. However, naive CD4+ cells from Tg mice maintained the capacity to differentiate into these lineages in response to polarizing cytokines in vitro. Expression of Il17, Il22, S100a8 and Ccl20 was enhanced in oral mucosal tissue of non-Tg, but not of Tg mice, after oral infection with C. albicans. Treatment of infected Tg mice with the combination of IL-17 and IL-22, but not IL-17 or Il-22 alone, significantly reduced oral burdens of C. albicans and abundance of Candida hyphae in the epithelium of tongues of infected Tg mice, and restored the ability of the Tg mice to up-regulate expression of S100a8 and Ccl20 in response to C. albicans infection.

CONCLUSIONS

These findings demonstrate that defective IL-17- and IL-22-dependent induction of innate mucosal immunity to C. albicans is central to the phenotype of susceptibility to OPC in these HIV transgenic mice.

Impact of tooth loss on oral and systemic health

Periodontitis is a primarily bacterial infection that is common in dentate individuals, while denture stomatitis is a predominantly fungal infection that is common among denture wearers. Both infections may increase a patient's risk for chronic systemic infection dissemination, and may in turn increase the risk of chronic, inflammatory-based systemic diseases. Systemic diseases for which chronic oral infections are believed to confer attributable risk include atherosclerotic and coronary disease, stroke, chronic obstructive pulmonary disease, diabetes, and hypertension. It appears that invasive oral pathogens trigger a systemic inflammatory response via mediators released by the cardiovascular system and liver, putting the patient at increased risk for these diseases. Data comparing gene expression between denture wearers with and without denture stomatitis (and associated Candida albicans infections) has demonstrated unique up- and down-regulation patterns for a number of genes. It appears that down-regulated genes (whose functions are thereby diminished) are associated with reduced epithelial barrier integrity. By contrast, there appears to be an association between up-regulated genes (which have enhanced function) and inflammatory responses that facilitate the ability of C. albicans to bind with and penetrate the oral mucosa. Molecular biological approaches suggest that future therapeutic development could target reducing either the local inflammatory processor, the binding and attachment of C. albicans to the oral mucosa, or both. Ongoing investigations are attempting to incorporate interventions into matrices, to provide a local and sustained presence to therapeutic interventions.

Elucidating role of salivary proteins in denture stomatitis using a proteomic approach

Denture stomatitis (DS) is the most common oral pathology among denture wearers, affecting over one-third of this group. DS is usually associated with C. albicans. However, unlike other oral candidiasis, most DS patients have intact host immunity. The presence of a denture alone is usually sufficient for DS. Saliva and its protein contents can theoretically predispose some denture wearers to DS and others resistant toward DS. Here we proposed for the first time to define salivary proteomic profiles of denture wearers with and without DS. SELDI-TOF/MS analysis suggests that there is a proteomic differentiation among control, localized and generalized DS. Based on initial SELDI-TOF/MS profiling, we further used reversed phase liquid chromatography, MALDI-TOF/MS, and LC-MS/MS to characterize the salivary proteins associated with DS. Nineteen proteins based on SELDI-TOF/MS profiling were found including cystatin-SN, statherin, kininogen-1, desmocollin-2, carbonic anhydrase-6, peptidyl-prolyl cis-trans isomerase A like peptides, cystatin C, and several immunoglobulin fragments. The proteomic content gives evidence of the interaction between host tissue, saliva, and candida. Further examination in larger populations of these proteins may help to gain a better understanding of DS pathological processes and improve DS treatments.

Bacteria and Candida yeasts in inflammations of the oral mucosa in children with secondary immunodeficiency

BACKGROUND

Oral microbial flora and a damaged oral mucosa may increase the risk of bacteriemia, fungemia and complications in immunocompromised patients.

AIM OF THE STUDY

Assessment of presence: bacteria and Candida spp. in different oral lesions, and the incidence of bacteremia in the case of a damaged mucosa in transplant recipients and patients receiving anti-tumour chemotherapy.

MATERIAL AND METHOD

Forty-five patients – 18 months to 18 years of life, were included (20 – organ recipients, 14– anti-tumour chemotherapy, 11 – control group). Clinical, oral mucosa examination focused on the type, severity and site of lesions, and microbiology assessed the presence of bacteria and fungi in the material from lesions. Blood cultures were performed in ten immunocompromised patients with manifestations of systemic infection. The control material consisted of blood cultures made prior to the onset of oral lesions and after 4–6 weeks following their remission in a diagnosed bacteremia. The statistical analysis was performed.

RESULTS

In the subjects with secondary immunodeficiency, among other coagulase-negative Staphylococcus (CoNS), Candidia spp. were more frequent. In cancer patients, mucositis was associated with Candida spp., Streptococcus spp. Organ recipients with stomatitis exhibited the presence of CoNS, Streptococcus viridians and other. Oral lesions in the control group contained Haemophilus parainfluenzae, Neisseria spp. and Staphylococcus aureus. In 30% of immunocompromised patients, oral lesions were accompanied by bacteremia.

CONCLUSIONS

A correlation has been found between oral lesions and the presence of S. aureus in patients without secondary immunodeficiency, and of CoNS, Enterococcus spp., Candida spp. in immunocompromised patients.

[Experimental oral candidiasis in healthy and immunocompromised BALB/c mice]

Oral candidiasis which is the most common type of Candida infections affecting humans, is most frequently caused by C.albicans. Immune response of the host, as well as a variety of virulence factors of the causative agent, play important roles in the development of Candida infections. The colonization rate of Candida in the oral cavity of healthy individuals, is between 25-30%, however, this rate is reported to be increased in immunosuppressive subjects. In our study, we established an oral candidiasis model with C.albicans in healthy and experimentally immunocompromised mice and aimed to compare Candida colonization rates and histopathological changes occurred in the tongue and esophagus tissues of the animal groups. A total of 21 BALB/c mice were grouped as control (Group 1; n= 7), healthy (Group 2; n= 7) and immunocompromised (Group 3; n= 7) groups. Immunosuppression in mice was performed by subcutaneous injection of prednisolone. For experimental oral candidiasis, cotton swab impregnated with C.albicans strains which did not have acid proteinase and phospholipase enzyme activity, no biofilm production, and sensitive to fluconazole and amphotericin B, were used. In the control group, physiological saline solution was used instead of C.albicans strain. In the forth day of experimental oral candidiasis model swab samples taken from the dorsal tongue surface of mice were evaluated by quantitative cultivation method. No yeast colonies were detected in Group 1 while more significant number of yeast colonies were observed in Group 3 compared to Group 2 (p= 0.002). Tongue and esophagus tissues of mice were stained with hematoxylin-eosin and periodic acid schiff staining and evaluated in terms of inflammatory response, abscess formation, vascular congestion, vasodilation and for the presence of yeast and hyphae. When the inflammation in esophagus was considered, statistically significant difference was determined between group 1 and group 3 (p= 0.023), however, no difference was detected between group 2 and 3 (p= 0.107). The level of inflammation in tongue tissue exhibited no difference between groups 2 and 3 (p= 0.317) while the difference was significant when these groups were compared to the control group (p= 0.00, p= 0.002, respectively). Similarly, the level of congestion in tongue tissue exhibited no difference between groups 2 and 3, however, the difference was significant when compared to the control group. To enlighten the relation between host immune status and oral candidiasis caused by C. albicans, further larger-scale studies also concerning the various virulence factors of the infectious agent, should be conducted by the use of experimental animal models which may successfully guide us in this regard.

A biphasic innate immune MAPK response discriminates between the yeast and hyphal forms of Candida albicans in epithelial cells

Discriminating between commensal and pathogenic states of opportunistic pathogens is critical for host mucosal defense and homeostasis. The opportunistic human fungal pathogen Candida albicans is also a constituent of the normal oral flora and grows either as yeasts or hyphae. We demonstrate that oral epithelial cells orchestrate an innate response to C. albicans via NF-κB and a biphasic MAPK response. Activation of NF-κB and the first MAPK phase, constituting c-Jun activation, is independent of morphology and due to fungal cell wall recognition. Activation of the second MAPK phase, constituting MKP1 and c-Fos activation, is dependent upon hypha formation and fungal burdens and correlates with proinflammatory responses. Such biphasic response may allow epithelial tissues to remain quiescent under low fungal burdens while responding specifically and strongly to damage-inducing hyphae when burdens increase. MAPK/MKP1/c-Fos activation may represent a “danger response” pathway that is critical for identifying and responding to the pathogenic switch of commensal microbes.

Oral candidiasis in immunosuppressed children and young adults after liver or kidney transplantation

PURPOSE

Candidiasis is an infectious complication in organ transplant recipients resulting from the patients' immunodeficiency and virulence of fungi pathogens. The purpose of this study was to evaluate the frequency of Candida spp. and identify their presence in the oral lesions of graft recipients.

METHODS

This study included 185 patients, 1.5 to 25.2 years of age (mean = 13.1 +/- 4.2 years) who were receiving combined immunosuppression treatment after kidney or liver transplantation and 70 control subjects. Evaluation included clinical oral examination, mycology, and statistical analysis.

RESULTS

Candida spp. colonies were found in the oral mucosa of 63 (34%) graft recipients and in 19 (27%) control subjects. Candida albicans was the most prevalent species. This study showed that, regardless of the type of the organ transplant and immunosuppression, frequent, regular oral follow-up and mycologic tests are recommended. Diagnosing increased density of Candida spp. colonies in the oral cavity will help initiate early antifungal treatment.

CONCLUSIONS

Candida spp. prevalence in the oral cavity in transplant recipients was higher than in immunocompetent control subjects. Kidney or liver transplantation predisposes one to the development of an increased density of Candida spp. colonies.

How the host fights against Candida infections

Candida albicans is the predominant cause of both superficial and invasive forms of candidosis, although the proportion of serious infections attributed to other members of the genus is rising.. The spectrum of host defences include cell mediated immunity which is comprised of cytokine release by lymphocytes and activation of natural killer cells and lymphocytes by interleukins.. An increasing body of evidence supports a role for specific antibody in protection against invasive Candida infection. Clinical observations indicate that mucocutaneous Candida infections are commonly associated with defective cell-mediated immune responses. Innate immunity is the dominant protective mechanism against disseminated candidosis. Quantitative and qualitative abnormalities of neutrophils and monocytes are associated with systemic candidosis. In the present review virulence factors and the spectrum of immune responses are discussed in relation to the perspective for the development of appropriate vaccines against Candida. Here we present an overview of toll-like receptor signalling, cellular-dependent responses, the role of specific antibodies in protection against Candida, and the array of immune mechanisms that operate in gastrointestinal, vaginal and oral candidosis.

Oral candidosis and its role in immunocompromised patients

The increased incidence of invasive candidosis in numerous categories of patients, including neonates, cancer patients, AIDS patients and patients who have undergone organ transplantation, is of great concern for the physicians involved. The manifestations of candidosis are numerous, and various clinical entities such as localized and disseminated infection have to be considered separately. All types of localized candidosis per se are usually not the main cause of disseminated disease. However, spreading of the mycotic pathogens in the gastrointestinal tract could induce disseminated candidosis. Prophylactic measurements in risk patients and consequent local and, if necessary, systemic treatment is recommended in these clinical entities.

Th17 cells and IL-17 receptor signaling are essential for mucosal host defense against oral candidiasis

The commensal fungus Candida albicans causes oropharyngeal candidiasis (OPC; thrush) in settings of immunodeficiency. Although disseminated, vaginal, and oral candidiasis are all caused by C. albicans species, host defense against C. albicans varies by anatomical location. T helper 1 (Th1) cells have long been implicated in defense against candidiasis, whereas the role of Th17 cells remains controversial. IL-17 mediates inflammatory pathology in a gastric model of mucosal candidiasis, but is host protective in disseminated disease. Here, we directly compared Th1 and Th17 function in a model of OPC. Th17-deficient (IL-23p19(-/-)) and IL-17R-deficient (IL-17RA(-/-)) mice experienced severe OPC, whereas Th1-deficient (IL-12p35(-/-)) mice showed low fungal burdens and no overt disease. Neutrophil recruitment was impaired in IL-23p19(-/-) and IL-17RA(-/-), but not IL-12(-/-), mice, and TCR-alphabeta cells were more important than TCR-gammadelta cells. Surprisingly, mice deficient in the Th17 cytokine IL-22 were only mildly susceptible to OPC, indicating that IL-17 rather than IL-22 is vital in defense against oral candidiasis. Gene profiling of oral mucosal tissue showed strong induction of Th17 signature genes, including CXC chemokines and beta defensin-3. Saliva from Th17-deficient, but not Th1-deficient, mice exhibited reduced candidacidal activity. Thus, the Th17 lineage, acting largely through IL-17, confers the dominant response to oral candidiasis through neutrophils and antimicrobial factors.

Oral mucosal cell response to Candida albicans in transgenic mice expressing HIV-1

Controlled studies on the immunopathogenesis of mucosal candidiasis in HIV infection have been hampered by the lack of a relevant animal model. We have previously reported that oral Candida infection in CD4C/HIV transgenic mice expressing gene products of HIV-1 in immune cells and developing an AIDS-like disease closely mimics oropharyngeal candidiasis in human HIV infection. The role of defective dendritic cells and CD4+ T cells in impaired induction of protective immunity and in the phenotype of chronic oral carriage of C. albicans can now be investigated under controlled conditions in these transgenic mice.

Oral manifestations as predictors of immune suppression in a HIV-/AIDS-infected population in south India

The objectives of the study are to evaluate the relationship between common HIV-related oral lesions and absolute CD4+ count, age, gender, and medication used and to assess the sensitivity, specificity, positive and negative predictive value of oral manifestations for low absolute CD4+ counts. HIV-positive patients, 200, from south India were selected, whose absolute CD4+ counts were determined within 2 weeks of oral examination. Sociodemographic data was obtained using a structured questionnaire. Oral manifestations were diagnosed according to presumptive criteria of EEC-clearinghouse classification (1993). Four or more concurrent oral lesions were statistically significant with low CD4+ counts <200 cells/mm3 (P = 0.005). The highest and lowest mean CD4+ cell counts were seen in individuals with linear gingival erythema (LGE; 172.5 cells/mm(3)) and pseudomembranous candidiasis (PC; 87 cells/mm(3)), respectively. Smoking, age (<35 years), and males had a positive association with oral hairy leukoplakia (OHL; P < 0.05). Patients with CD4+ counts < 200 cells/mm(3) were associated with 15 times greater risk of PC and four times at greater risk for occurrence of any oral manifestation. Concurrent oral manifestations (>or=4) were good predictors (80-100%) of severe immune suppression. In most resource poor countries where facilities for undertaking CD4+ counts are not available, the presence of concurrent oral manifestations may be used as an indicator of deteriorating immune status.

Microbiological and immunological features of oral candidiasis

Candida albicans(C. albicans) is the major infectious agent of oral candidiasis, and both innate immunity and cell-mediated immune response participate in the control of the fungal infections. The aim of this study was to correlate the clinical forms of oral candidiasis with the number of colony forming units (CFU) of C. albicans in saliva and to characterize T cell response in patients with oral candidiasis. Participants included 75 subjects: 36 with lesions of candidiasis and 39 without lesions of oral candidiasis. A 2-ml sample of saliva was collected from all subjects for microbiological analysis. Cytokine levels were determined by ELISA in supernatants of peripheral blood mononuclear cells of 25 patients with oral candidiasis, after in vitro stimulation with C. albicans antigens. In 48% of patients, no association was observed with denture use. C. albicans was detected in the saliva of 91.7% of patients with oral candidiasis, and there was an association between the number of CFU and the presence of oral lesions. A type Th1 immune response was observed in supernatants of peripheral blood mononuclear cells stimulated with C. albicans antigens. In contrast, IL-5 and IL-10 levels were very low or undetectable. Together, this study shows an association between clinical forms of oral candidiasis and the number of colonies of C. albicans in saliva, and that a systemic immune response characterized by the production of TNF-alpha and IFN-gamma is observed in patients with oral candidiasis.

Soluble CD14 and toll-like receptor-2 are potential salivary biomarkers for oral lichen planus and burning mouth syndrome

Oral lichen planus (OLP) and burning mouth syndrome (BMS) are chronic conditions affecting the oral mucosa characterized by pain and burning sensation. Saliva plays a significant role in the maintenance of physical and functional integrity of normal oral mucosa. Identification of potential "salivary biomarkers" for early diagnosis and/or monitoring of human diseases is being explored. We investigated the soluble forms of innate immune associated proteins CD14 and toll-like receptor-2 in unstimulated whole saliva (UWS) as potential biomarkers for OLP and BMS. Our results suggest that the levels of sCD14 and sTLR-2 in UWS were upregulated in OLP and BMS respectively. In addition, oral epithelial cells in the saliva of patients with OLP and BMS exhibited elevated levels of CD14 mRNA and decreased levels of TLR-2 mRNA. Interestingly, presence of co-existent oral candidiasis nullified these changes.

IL-1alpha, IL-1ra and IL-8 are differentially induced by Candida in experimental oral candidiasis

OBJECTIVE

To investigate the expression of interleukin-1alpha (IL-1alpha), IL-1ra and IL-8 by the oral epithelium challenged by various Candida species.

MATERIALS AND METHODS

In vitro candidiasis was induced by C. albicans wild type SC5314, its EFG1, CPH1 and secretory aspartyl proteinase (SAP) mutants and, ATCC isolates of C. albicans, C. tropicalis and C. dubliniensis using a reconstituted human oral epithelium (RHOE) model. IL-1alpha, IL-1ra and IL-8 levels in culture media were quantified by an enzyme-linked immunosorbent assay at 12, 24 and 48 h. Fungal invasion and IL-1ra expression in RHOE were detected by periodic acid-Schiff staining and immunohistochemistry.

RESULTS

Overall, the invasive Candida induced relatively higher levels of IL-1alpha, IL-1ra and IL-8 in the culture media than the noninvasive isolates. IL-1alpha and IL-1ra levels induced by Candida with hyphal invasion were significantly higher (P < 0.05) than those induced by the isolates without hyphal invasion at 12, 24 and 48 h. Candida albicans SC5314 induced IL-1ra expression in RHOE at 12 and 24 h but not at 48 h consistent with its hyphal invasion; while the noninvasive mutants and non-albicans Candida induced IL-1ra expression at 48 h.

CONCLUSIONS

The cytokine expression profiles in experimental oral candidiasis may be associated with the invasive potential of Candida.

A possible CD1a Langerhans cell-mast cell interaction in chronic hyperplastic candidosis

AIMS

T lymphocyte-antigen-presenting cell (APC) interaction plays a central role in T lymphocyte activation and APC maturation. We therefore studied the CD1a-positive Langerhans cells with respect to receptor activator of nuclear factor kappa B ligand (RANKL)-positive cells in chronic hyperplastic candidosis (CHC).

MATERIALS AND METHODS

Tissue sections of CHC were compared with leukoplakia and healthy oral mucosa using RANKL and CD1a monoclonal antibodies in an avidin-biotin peroxidase complex protocol. Two different antigen-retrieval protocols, pepsin preincubation and Tris-EDTA heat treatment, were used.

RESULTS

CD1a-positive Langerhans cells were in healthy and leukoplakia epithelium found in the middle layer, but in CHC in all layers of the epithelium, at the basement membrane and as mononuclear round cells in the lamina propria. Use of pepsin digestion enabled studies of mast cells and their activation in the form of degranulation of RANKL.

CONCLUSIONS

The numerical, morphological and topographical versatility of the CD1a-positive Langerhans cells in CHC can be clarified by dendritic cell (DC) recruitment into the epithelium. RANK-positive and RANKL-sensitive DCs have ample opportunity to interact with local T lymphocytes. Use of an optimized antigen-retrieval protocol enabled demonstration of an active engagement (degranulation) of mast cells, which represent a rapidly available source of soluble RANKL.

Candida glabrata: an emerging oral opportunistic pathogen

Following the widespread use of immunosuppressive therapy and broad-spectrum antimycotic prophylaxis, C. glabrata has emerged as an important opportunistic pathogen in the oral mucosa. In the past, studies on the virulence factors and host-pathogen interactions of this organism were scarce, but continued to rise in recent years. Denture-wearing, immunosuppression, antibiotic therapy, and aging are risk factors for oral colonization or infection with C. glabrata. Compared with C. albicans, C. glabrata exhibits lower oral keratinocyte-adherence capacity, but higher denture-surface-adherence ability. The role of extracellular hydrolase production in the virulence of this organism does not appear to be as important as it is in C. albicans pathogenesis. Although traditionally thought of as a non-transforming yeast organism, both phenotypic switching and pseudohyphal formation have recently been identified in C. glabrata, but their role in pathogenesis is not known. With the exception of granulocyte monocyte colony-stimulating factor, C. glabrata triggers a lower proinflammatory cytokine response in oral epithelial cells than does C. albicans, in a strain-dependent manner. C. glabrata is less susceptible to killing by human beta-defensins than is C. albicans and exhibits various degrees of resistance to the antifungal activity of salivary histatins and mucins. In addition, C. glabrata possesses both innate and acquired resistance against antifungal drugs, due to its ability to modify ergosterol biosynthesis, mitochondrial function, or antifungal efflux. This resistance allows for its relative overgrowth over other susceptible species and may contribute to the recent emergence of C. glabrata infections in chronically immunocompromised populations. Further investigations on the virulence and host-pathogen interactions of C. glabrata are needed to better define the pathogenesis of oral C. glabrata infection in susceptible hosts.

Murine model of concurrent oral and vaginal Candida albicans colonization to study epithelial host-pathogen interactions

We report the creation of a new low-estrogen murine model of concurrent oral and vaginal C. albicans colonization that resembles human candidal carriage at both mucosal sites. Weekly estrogen administration of 5 microg intramuscular and subcutaneously was optimal for enhancement of oral colonization and was essential for vaginal colonization. In BALB/c mice, a number of C. albicans clinical isolates (n=3) colonized both oral and/or vaginal sites, but only strain 529L colonized 100% of mice persistently for over 5 weeks. Laboratory strains SC5314 and NCPF 3153 did not colonize the model; however, NCPF 3156 showed vaginal colonization up to week 5. Prior passaging through mice enhanced subsequent colonization of SC5314. Intranasal immunization with a C. albicans virulence antigen (secreted aspartyl proteinase 2) significantly reduced or abolished the fungal burden orally and vaginally by week 2 and 7. Our concurrent model of mucosal colonization reduces the numbers of experimental mice by half, can be used to assess potential vaccine candidates, and permits the detailed analysis of host-fungal interactions during the natural state of Candida colonization.

Chemokine receptor expression in HIV-positive persons with oropharyngeal candidiasis

OBJECTIVE

In HIV+ persons with reduced CD4+ T cells, oropharyngeal candidiasis (OPC) is often associated with the accumulation of CD8+ T cells at the epithelial/lamina propria interface within the lesion together with increased tissue-associated cytokines and chemokines. Despite this reactivity, a dysfunction in the ability of the CD8+ cells to reach the organism at the outer epithelium is postulated. The purpose of this study was to examine chemokine receptors present in the OPC lesions for a potential role in susceptibility to infection.

METHODS

Biopsies taken from buccal mucosa of HIV- persons, healthy mucosa of HIV+ OPC- persons, and OPC lesions were processed for protein immunohistochemical staining or RNA analysis by real-time PCR and Superarray.

RESULTS

There was little change in expression of chemokine receptors at the protein or RNA level between OPC+ and OPC- tissue. At the protein level, increases occurred in OPC+ persons only if associated with CD8 cells. In the Superarray, of the 22 chemokine receptor mRNAs expressed, c. 90% remained unchanged (< 1.0-fold change) between HIV- and HIV+ tissue and between HIV+ OPC- and HIV+ OPC+ tissue.

CONCLUSION

Tissue-associated chemokine receptor expression does not appear to contribute to the dysfunction in cellular migration associated with susceptibility to OPC.

Analysis of the Candida albicans - specific T-cell response and oropharyngeal Candida colonization in a cohort of HIV-1-infected patients

To investigate Candida epidemiology and immunologic correlates of protection in HIV-1 infected patients, we analyzed oral Candida colonization in correlation to the Candida-specific T-cell response measured by g-IFN ELISPOT using different Candida (C.) albicans strains. In 16/46 patients (13 asymptomatic, 3 with oral thrush), but in 0/28 controls, Candida (13 C. albicans, 1 C. lusitaniae, 1 C. krusei, 1 C. parapsilosis) was isolated. Candida specific T-cells were detected more frequently in controls (20/28) than in HIV-1+ subjects (16/46, p= 0.03). We observed a significant association of higher CD4 cell numbers with both detection of Candida specific T-cells and lack of oral Candida colonization, but there was no significant correlation of oral Candida colonization to the detection of Candida specific T-cells, viral load or antiretroviral therapy. Thus, local mucosal immunity seems to be more important in the pathogenesis of Candida colonization than circulating Candida specific T-cells. The pathogenic C. albicans strain K24122 was less frequently recognized by patients (6/46) than the laboratory adapted strain SC5314 (14/46, p= 0.03), whereas a similar recognition of both strains was observed in healthy controls. This indicates an impaired Candida-specific T-cell repertoire in HIV+ patients that could increase the risk of immune evasion by C. albicans.

Candida albicans HWP1 gene expression and host antibody responses in colonization and disease

In vivo expression of the developmentally regulated Candida albicans hyphal wall protein 1 (HWP1) gene was analysed in human subjects who were culture positive for C. albicans and had oral symptoms (n=40) or were asymptomatic (n=29), or had vaginal symptoms (n=40) or were asymptomatic (n=29). HWP1 mRNA was present regardless of symptoms, implicating hyphal and possibly pseudohyphal forms in mucosal carriage as well as disease. As expected, in control subjects without oral symptoms (n=10) and without vaginal symptoms (n=10) who were culture negative in oral and vaginal samples, HWP1 mRNA was not detected. However, exposure to Hwp1 in healthy culture-negative controls, as well as in oral candidiasis and asymptomatic mucosal infections, was shown by the existence of local salivary and systemic adaptive antibody responses to Hwp1. The results are consistent with a role for Hwp1 in gastrointestinal colonization as well as in mucosal symptomatic and asymptomatic infections. Overall, Hwp1 and hyphal growth forms appear to be important factors in benign and invasive interactions of C. albicans with human hosts.

Candida-induced oral epithelial cell responses

OBJECTIVE

Oropharyngeal candidiasis (OPC), caused by Candida albicans, is the most common oral infection in HIV(+) persons. Oral epithelial cells are considered important for innate host defense against OPC with production of cytokines in response to C. albicans and the ability to inhibit Candida growth in vitro. The purpose of this study was to determine if Candida similarly induces cytokines by oral epithelial cells from HIV(+) persons, including those with OPC, as well as to determine if cytokines can influence the oral epithelial cell anti-Candida activity.

METHODS

Supernatants from oral epithelial cells from HIV(+) persons with and without OPC cultured with Candida were evaluated for cytokines by ELISA, or cytokines were added to the standard growth inhibition assay using epithelial cells from HIV(-) persons.

RESULTS

Results showed low Candida-induced epithelial cell cytokine production from HIV(+) persons, but with some elevated proinflammatory cytokines (TNF-alpha, IL-6) in those with OPC compared to those without OPC. The addition of specific proinflammatory or Th cytokines had no effect on oral epithelial cell anti-Candida activity in healthy HIV(-) persons.

CONCLUSION

These results suggest that oral epithelial cells from HIV(+) persons can contribute at some level to the oral cytokine milieu in response to Candida during OPC, but that cytokines do not appear to influence oral epithelial cell anti-Candida activity.

Distinct roles for interleukin-12p40 and tumour necrosis factor in resistance to oral candidiasis defined by gene-targeting

Cell-mediated immunity is important for anti-Candida host defence in mucosal tissues. In this study we used cytokine-specific gene knockout mice to investigate the requirement for T helper type 1 (Th1) and Th2 cytokines in recovery from oral candidiasis. Knockout mice used in this study included interleukin-4 (IL-4), IL-10, IL-12p40, interferon-gamma (IFN-gamma), and tumour necrosis factor (TNF). The mice were challenged either orally or systemically with Candida albicans yeasts, and levels of colonization were determined. IL-12p40 knockout mice developed chronic oropharyngeal candidiasis, but were not more susceptible to systemic challenge. On the other hand, TNF knockout mice displayed increased susceptibility to both oral and systemic challenge, but only in the acute stages of infection. TNF apparently has a protective effect in the acute stages of both oral and systemic candidiasis, whereas IL-12p40 is essential for recovery from oral but not systemic candidiasis. The role of IL-12p40, and its relation to T-cell-mediated responses remain to be determined.

Expression of interleukin-8 and its receptor IL-8RA in chronic hyperplastic candidosis

INTRODUCTION

Neutrophils are the main opponents of Candida albicans in chronic hyperplastic candidosis. They migrate from the circulation to the epithelium where they form microabscesses. We therefore hypothesized that the neutrophil chemokine interleukin-8 (IL-8) might play a role in the neutrophil-Candida interaction.

METHODS

Biopsies from patients with chronic hyperplastic candidosis (n = 10) were stained using the avidin-biotin-peroxidase complex protocol for IL-8 and IL-8 receptor A and were compared to healthy control mucosa (n = 3). A set of C. albicans agar sections was similarly analysed.

RESULTS

In chronic hyperplastic candidosis lesions IL-8 was strongly expressed in both vascular endothelium and mucosal epithelium. Many resident and immigrant inflammatory cells, including intraepithelial neutrophils, were IL-8 receptor A positive. In addition, IL-8 (or an analogue) was found in the candidal mother cell in chronic hyperplastic candidosis and in agar, whereas the tips of the hyphae expressed IL-8 receptor A (or an analogue).

CONCLUSION

IL-8 may play a role in the recruitment of neutrophils from the vascular compartment to the epithelial microabscesses. C. albicans may have developed an ability to sense IL-8. The IL-8 ligand-receptor interaction may help to direct the growth of the IL-8-receptor-containing tips of the hyphae away from the IL-8-producing candidal cell body (a centrifugal growth pattern to facilitate host tissue penetration). Later, this ability might help to keep the vulnerable hyphal tips away from areas with high concentrations of host IL-8 and candidacidal neutrophils. We suggest that this phenomenon, in contrast to chemotropism, is named chemophobia.

Characterization of the immune status of CD8+ T cells in oral lesions of human immunodeficiency virus-infected persons with oropharyngeal Candidiasis

Oropharyngeal candidiasis (OPC) remains the most common oral infection in human immunodeficiency virus (HIV) disease. In a high percentage of HIV(+) persons with reduced CD4(+) T cells, oral lesions with Candida present at the outer epithelium have an accumulation of CD8(+) T cells at the epithelium-lamina propria interface associated with reduced expression of the mucosal cell-trafficking adhesion molecule E-cadherin. The purpose of the present study was to characterize the immune status of these CD8(+) T cells. Immunohistochemical staining for phenotypic and activation and costimulation markers was performed on frozen biopsy tissue sections from HIV(+) OPC(+) persons with accumulated CD8(+) T cells. CD8(+) T cells consisted primarily of central memory cells by virtue of positive CD45RO (memory) and CD27 (central memory) expression. However, concomitant negative expression of CD62L and CCR7 (effector memory) was suggestive of a transitioning memory phenotype within the tissue. Despite this, the cells are considered to be activated on the basis of positive expression of CD69. The CD8(+) T cells are not considered to be NK T cells or anti-HIV CD8(+) T cells because of negative or low expression of CD161 and vascular cell adhesion molecule, respectively. These results suggest that the accumulated mucosal migratory-challenged CD8(+) T cells are otherwise normal memory T cells in an activated state.

Correlation between CD4 count and intensity of Candida colonization in the oropharynx of HIV-infected/ AIDS patient

AIM

To know the correlation between CD4 count and intensity of Candida colonizations in the oropharynx of HIV-infected/AIDS patients, to get the prevalence of oropharyngeal candidiasis (OPC), and to know what kind of Candida species that causes oropharynx candidiasis of HIV-infected/AIDS patients.

METHODS

A cross-sectional study was conducted in HIV-infected/AIDS patients who came as outpatients and inpatients in Cipto Mangunkusumo Hospital. The patients were interviewed, physically examined, their CD4 counts were checked, and their mouth rinse samples were taken to be cultured. Candida species was identified in CHROMagar media, and data were processed.

RESULTS

From September 2004 until January 2005, 60 HIV-infected/AIDS patients were included in this study. There were 86.7% males and 13.3% females. Majority of the patients were from 20-30 years age group (85%). The most frequent transmission was among drug users (75%) followed by sexual contact (18.3%). The median of CD4 counts was 100 cells/il, ranged from 2 to 842 cells/il. Proportion of the OPC was 63.3% (CI 95% = 51.1 - 75.5). From 59 Candida isolates in this study, 74.58% were C. albicans. Candida non C. albicans species that were found in this trial were C. krusei, C. parapsilosis and C. tropicalis. There was significant correlation between low CD4 counts and high intensity of Candida colonization on the oropharynx of the subjects (r = -0.756).

CONCLUSION

There was strong negative correlation (r = -0.756) between CD4 count and intensity of Candida colonization in the oropharynx of HIV-infected/AIDS patients. Proportion of OPC in this study was 63.3%. The most frequent species found in the oropharynx of the subjects was C. albicans.

CD8+ T cells but not polymorphonuclear leukocytes are required to limit chronic oral carriage of Candida albicans in transgenic mice expressing human immunodeficiency virus type 1

Candida albicans causes oropharyngeal candidiasis (OPC) but rarely disseminates to deep organs in human immunodeficiency virus (HIV) infection. Here, we used a model of OPC in CD4C/HIV(Mut) transgenic (Tg) mice to investigate the role of polymorphonuclear leukocytes (PMNs) and CD8+ T cells in limiting candidiasis to the mucosa. Numbers of circulating PMNs and their oxidative burst were both augmented in CD4C/HIV(MutA) Tg mice expressing rev, env, and nef of HIV type 1 (HIV-1), while phagocytosis and killing of C. albicans were largely unimpaired compared to those in non-Tg mice. Depletion of PMNs in these Tg mice did not alter oral or gastrointestinal burdens of C. albicans or cause systemic dissemination. However, oral burdens of C. albicans were increased in CD4C/HIV(MutG) Tg mice expressing only the nef gene of HIV-1 and bred on a CD8 gene-deficient background (CD8-/-), compared to control or heterozygous CD8+/- CD4C/HIV(MutG) Tg mice. Thus, CD8+ T cells contribute to the host defense against oral candidiasis in vivo, specifically in the context of nef expression in a subset of immune cells.

Candida-host interactions in HIV disease: relationships in oropharyngeal candidiasis

Oropharyngeal candidiasis (OPC) caused by the commensal organism, Candida albicans, is the most common oral infection in HIV disease. Although cell-mediated immunity (CMI) by Th1-type CD4+ T-cells is considered the predominant host defense mechanism against OPC, other systemic or local immune mechanisms are critical when blood CD4+ T-cells are reduced below a protective threshold. For example, the Th cytokine profile in saliva may influence resistance or susceptibility to OPC. In OPC lesions, CD8+ T-cells become accumulated at the lamina propria-epithelium interface, suggesting some role for CD8+ T-cells against OPC. However, the absence of CD8+ T-cells close to Candida at the outer epithelium indicates that susceptibility to OPC involves a dysfunction in the CD8+ T-cells or in the micro-environment. Further evaluation of the buccal mucosa lesion showed that CD8 T-cell-associated cytokine and chemokine mRNA is increased compared with buccal mucosa from lesion-negative matched controls. The majority of CD8+ T-cells present possess the alphabeta T-cell receptor and several homing receptors (i.e., 4beta7, 4beta1, ebeta7). While several adhesion molecules are similar in OPC+ vs. OPC- persons, E-cadherin is reduced in the tissue of OPC+ persons. These results support evidence for a role for CD8+ T-cells against OPC, but suggest that a putative dysfunction in mucosal T-cell trafficking may be associated with susceptibility to infection. Similar levels of Candida-specific antibodies in persons with and without OPC confirmed a limited role for humoral immunity. Finally, oral epithelial cells inhibit the growth of Candida in vitro in a static rather than a cidal manner. Clinically, oral epithelial cell anti-Candida activity is reduced in HIV+ persons with OPC, compared with controls. The mechanism of action includes a strict requirement for cell contact by an acid-labile moiety on intact, but not necessarily live, epithelial cells, with no role for soluble factors. Taken together, host defense against OPC involves several levels of activity. The status and efficiency of local host defenses when blood CD4+ T-cells are not available appear to play a role in protection against or susceptibility to OPC.

Salivary IgA and oral candidiasis in asthmatic patients treated with inhaled corticosteroid

BACKGROUND

Inhaled corticosteroids are used for the treatment of bronchial asthma. Systemic side effects are rare, but local problems, such as oral candidiasis, can occur. Only a proportion of patients encounter this problem, and the mechanism of oral candidiasis induced by inhaled corticosteroids remains obscure. According to reports in immunodeficient patients, oral candidiasis is related to deficiencies in topical immunity, such as salivary IgA.

OBJECTIVES

We evaluated differences in salivary IgA between asthmatics in whom Candida was detected or not detected from the pharynges, respectively.

METHODS

Saliva was collected from 18 healthy controls and 37 asthmatic patients treated with inhaled corticosteroids. The amounts of total IgA and the Candida-specific IgA of the saliva were measured. Fungal culture of the pharyngeal wall was also performed.

RESULTS

There were no differences in salivary total IgA and Candida-specific IgA between healthy controls and culture-negative asthmatic patients. Salivary total IgA of Candida-positive asthmatic patients was significantly lower than that of Candida-negative patients. However, there was no difference in Candida-specific IgA levels between these two groups.

CONCLUSIONS

Our results suggest that inhaled corticosteroids can potentially decrease salivary total IgA but that host factors are also important in the development of oral candidiasis.

Susceptibility to Melaleuca alternifolia (tea tree) oil of yeasts isolated from the mouths of patients with advanced cancer

Yeasts that are resistant to azole antifungal drugs are increasingly isolated from the mouths of cancer patients suffering from oral fungal infections. Tea tree oil is an agent possessing antimicrobial properties that may prove useful in the prevention and management of infections caused by these organisms. In this study, 301 yeasts isolated from the mouths of 199 patients suffering from advanced cancer were examined by an in vitro agar dilution assay for susceptibility to tea tree oil. All of the isolates tested were susceptible, including 41 that were known to be resistant to both fluconazole and itraconazole. Clinical studies of tea tree oil as an agent for the prevention and treatment of oral fungal infections in immunocompromised patients merit consideration.

Candida albicans-infected oral epithelial cells augment the anti-fungal activity of human neutrophils in vitro

Oropharyngeal candidiasis (OPC) is the most common opportunistic infection in immunosuppressed patients. In OPC, Candida albicans persists intraepithelially triggering inflammatory events, without generally causing invasive infection. Since neutrophils play an important role in preventing invasive infection and since they establish contact with the microorganisms only within the epithelial cell layer, we examined the ability of Candida-infected oral epithelial cells to augment neutrophil-mediated hyphal damage in vitro. We found that challenge of neutrophils with hyphal organisms in the presence of C. albicans-infected oral epithelial cell supernatants resulted in a significantly greater suppression of hyphal cell metabolic activity compared to basal neutrophil anti-fungal function. Anti-hyphal activity in response to these supernatants was partly inhibited by neutralizing anti-IL-1alpha antibody and IL-1 receptor antagonist. Control supernatants from uninfected oral epithelial cells, as well as C. albicans conditioned-medium had a much less pronounced effect on neutrophil anti-fungal activity, which was not inhibited by these cytokine antagonists. We conclude that oral epithelial cells can act as activators of neutrophil anti-hyphal function, an effect that can be partly attributed to the generation of immunomodulatory cytokines during the interaction of oral mucosal cells with the pathogen.

Oral epithelial cell antifungal activity: approaches to evaluate a broad range of clinical conditions

Anti-Candida activity by oral epithelial cells is considered one of several innate mucosal defense mechanisms against oropharyngeal candidiasis (OPC). OPC is the most common fungal infection in HIV disease. Previously we reported that oral epithelial cell anti-Candida activity is reduced in those with OPC, potentially representing a contributing factor to OPC. However, testing clinical epithelial cells possessing high levels of Candida has been limiting due to high background in the assay controls. HIV+ smokers often develop OPC sooner than non-smokers during progression to AIDS, suggesting additional immune aberrations. The purpose of this study was to design a means to reduce Candida associated with epithelial cells collected from saliva without affecting their in vitro growth inhibitory activity, and to employ that approach to evaluate antifungal activity in HIV+ smokers. To do so, oral epithelial cells with and without known levels of Candida were subjected to various treatments including azole, polyene, or echinocandin antifungal drugs or fixation followed by the standard growth inhibition (GI) assay. The results indicated that antifungal drugs, while effectively reducing cell-associated Candida, also affected epithelial cell function. In contrast, fixation with paraformaldehyde eliminated cell-associated Candida and had minimal effects on epithelial cell anti-Candida activity. Employing the fixation design that allowed a broad range of patients to be evaluated showed no difference in oral epithelial anti-Candida activity between HIV+ smokers and non-smokers. Therefore, oral epithelial cell antifungal activity does not appear compromised in those who smoke, reducing it as a contributing factor in susceptibility to premature OPC.

Synchronous kinetics of CD4+ lymphocytes and viral load before the onset of oral candidosis and hairy leukoplakia in a cohort of Mexican HIV-infected patients

An observational, prospective, longitudinal cohort study was performed at the AIDS Clinic of a tertiary care institution in Mexico City to determine the association of viral load (VL) and CD4+ lymphocyte kinetics with the development of oral candidosis (OC) and hairy leukoplakia (HL). Participants were HIV-infected adult subjects, without a history of or current OC or HL, not receiving HAART. Oral examinations were performed at baseline and every month for evidence of OC or HL; CD4+ and VL determinations were done at baseline, at 6-month intervals, when oral lesions were detected, and 2 months later. Affected subjects (OL group) by OC or HL had clinical intervals defined before (antecedent), during (concurrent), and after their development. In the nonaffected individuals (NA group), 6-month intervals were determined. Differences (changes) along the clinical and study intervals were calculated for CD4+ and VL. The median study time was 178 (range: 31-924) days; 99 patients were included. The 2-year cumulative incidence of either oral lesion was 54% (49.5% for OC and 33.2% for HL). In the OL group (31 patients) a progressive and continuous decrease of CD4+ was found in the antecedent interval followed by a significant increase in VL in the concurrent period. The NA group showed a significant fall in CD4+ by semester 3, without a significant rise of VL in the following semester. The effect of CD4+ remained significant in a multivariate analysis. This study has shown that the onset of OC and/or HL is heralded by the sequence of a sustained reduction of CD4+, followed by a sharp increase of VL. In the multivariate analysis, the decrease in CD4+ lymphocytes appeared to be the predominant factor predicting the appearance of these oral lesions. Their potential use as markers of a recent change in the immunologic and virologic status of HIV-infected individuals is emphasized.