Immunity in vaginal candidiasis

From plants to particles: herbal solutions and nanotechnology combating resistant vulvovaginal candidiasis

Despite having current advanced therapy, vulvovaginal candidiasis (VVC) remains a common yet debated healthcare-associated topic worldwide due to multi-drug resistance Candida species. In our review, we outlined and highlighted upcoming values with scope of existing and emerging information regarding the possibility of using various natural molecules combined with modern technology that shows promising anti-candida activity in VVC. Furthermore, in this review, we compiled herbal drug molecules and their nanocarriers approach for enhancing the efficacy and stability of herbal molecules. We have also summarized the patent literature available on herbal drug molecules and their nanoformulation techniques that could alternatively become a new innovative era to combat resistance VVC.

Essential oil and nanocarrier-based formulations approaches for vaginal candidiasis

An exclusive site for local drug delivery is the vagina, especially for vaginal infections. The fungus Candida albicans causes vaginal infection known as vulvovaginal candidiasis, a highly prevalent and recurrent gynaecological disease among women. Vaginal candidiasis affects over 75% of women at a certain point in their life and has a recurrence rate of 40-50%. Medicinal plants provide some very effective phytoconstituents which when delivered as nanosystems have enhanced therapeutic action and efficacy by alteration in their characteristics. Antifungal drugs are used to treat these conditions, alternative medicine is required for prophylaxis and improved prognosis. The current review focuses on the research carried out on various nanocarrier-based approaches and essential oil-based formulations for vaginal candidiasis.

HLA-DRB1 alleles as predisposing and resisting factor in women suffering from vulvovaginal candidiasis

BACKGROUND

Vulvovaginal candidiasis (VVC) is a vaginal mucosal infection that usually affects women in their reproductive age. When the signs of VVC persist on a daily basis or last for a long time and repeat at least three times per year, the disease is considered chronic and recurrent.

OBJECTIVE

The purpose of this study was to evaluate the frequency of HLA-DRB1 alleles in patients with recurrent vulvovaginal candidiasis (RVVC).

STUDY DESIGN

120 patients with RVVC and 136 age-matched healthy controls underwent low-resolution HLA-DRB typing performed using the polymerase chain reaction-sequence-specific primers (PCR-SSP) technique.

RESULTS

In the present work, we studied different genes that encode HLA-DRB (HLA-DRB1 / HLA-DRB3 / HLA-DRB4 / HLA-DRB5) and showed that HLA-DRB1×14, found in 25% of the patients. In the present study, the significant frequency of HLA-DRB1×10 in the control group suggests a resistant role of this allele to RVVC infections CONCLUSIONS: In the HLA-DRB region, the DRB1×14 allele showed a higher frequency in the patients with RVVC than in the controls. Moreover, the higher frequency of DRB1×10 observed in the controls than in the patients with RVVC. These results demonstrate the HLA-DRB1 alleles are in relation with both susceptibility and immunity factors in RVVC infection and possible susceptible role of HLA-DRB1×14.

Vulvovaginal Candidosis (Excluding Mucocutaneous Candidosis): Guideline of the German (DGGG), Austrian (OEGGG) and Swiss (SGGG) Society of Gynecology and Obstetrics (S2k-Level, AWMF Registry Number 015/072, September 2020)

Aim The aim of this official guideline, published and coordinated by the German (DGGG), Austrian (OEGGG) and Swiss (SGGG) Societies of Gynecology and Obstetrics in collaboration with the DMykG, DDG and AGII societies, was to provide consensus-based recommendations obtained by evaluating the relevant literature for the diagnosis, treatment and management of women with vulvovaginal candidosis. Methods This S2k guideline represents the structured consensus of a representative panel of experts with a range of different professional backgrounds commissioned by the Guideline Committee of the above-mentioned societies. Recommendations This guideline gives recommendations for the diagnosis, management, counseling, prophylaxis and screening of vulvovaginal candidosis.

Guideline: Vulvovaginal candidosis (AWMF 015/072, level S2k)

Approximately 70-75% of women will have vulvovaginal candidosis (VVC) at least once in their lifetime. In premenopausal, pregnant, asymptomatic and healthy women and women with acute VVC, Candida albicans is the predominant species. The diagnosis of VVC should be based on clinical symptoms and microscopic detection of pseudohyphae. Symptoms alone do not allow reliable differentiation of the causes of vaginitis. In recurrent or complicated cases, diagnostics should involve fungal culture with species identification. Serological determination of antibody titres has no role in VVC. Before the induction of therapy, VVC should always be medically confirmed. Acute VVC can be treated with local imidazoles, polyenes or ciclopirox olamine, using vaginal tablets, ovules or creams. Triazoles can also be prescribed orally, together with antifungal creams, for the treatment of the vulva. Commonly available antimycotics are generally well tolerated, and the different regimens show similarly good results. Antiseptics are potentially effective but act against the physiological vaginal flora. Neither a woman with asymptomatic colonisation nor an asymptomatic sexual partner should be treated. Women with chronic recurrent Candida albicans vulvovaginitis should undergo dose-reducing maintenance therapy with oral triazoles. Unnecessary antimycotic therapies should always be avoided, and non-albicans vaginitis should be treated with alternative antifungal agents. In the last 6 weeks of pregnancy, women should receive antifungal treatment to reduce the risk of vertical transmission, oral thrush and diaper dermatitis of the newborn. Local treatment is preferred during pregnancy.

Intravaginal poly-(D, L-lactic-co-glycolic acid)-(polyethylene glycol) drug-delivery nanoparticles induce pro-inflammatory responses with Candida albicans infection in a mouse model

In a recent study, using an in vitro model to study intravaginal nanoparticle exposure during yeast infections, we demonstrated that C. albicans exposure suppressed apoptotic gene expression and induced oxidative stress and pyroptosis in vaginal epithelial cells. The mucous-penetrating drug delivery nanoparticles made from poly-(D, L-lactic-co-glycolic acid)-(polyethylene glycol) induced cytotoxicity by activating apoptosis, endoplasmic reticulum (ER) stress, oxidative stress, and DNA damage repair responses alone and, in some cases with C. albicans. In the current study we evaluated the effects of fluorescently-labelled nanoparticles in CBA/J mice challenged intravaginally for two hours followed by intravaginal challenge with C. albicans for 18 hours. Nanoparticle treatment increased systemic translocation of C. albicans threefold in the heart. C. albicans also increased systemic distribution of the nanoparticles fivefold in the heart. Flow cytometric assays showed co-localization of the nanoparticles with epithelial cells, macrophages and dendritic cells. Nanoparticle-treated, C. albicans-infected mice exhibited induction of autophagy, ER stress, apoptosis, and inflammatory serum cytokines. C. albicans infection was associated with pyroptosis and suppressed expression of ER stress and apoptosis-related genes. Induction of apoptosis during nanoparticle treatment and in nanoparticle-treated-C. albicans infected mice was observed as DNA damage responses, mitochondrial depolarization and (Poly [ADP-Ribose] Polymerase) cleavage. C. albicans infection was associated with increased mRNA expression of anti-apoptotic genes. Both C. albicans infection and nanoparticle treatment showed enhanced chemoattraction of dendritic cells and polymorphonuclear cells to factors in vaginal washings in a chemotaxis assay. This study shows that both intravaginal treatment of mice with the nanoparticles and infection with C. albicans induce cytotoxic and inflammatory responses. C. albicans also suppressed cell apoptosis. These results clarify our understanding of how nanoparticles modulate host cellular responses during C. albicans infection and will be applicable for future research and development of intravaginal nanomedicines.

Microbiota in vaginal health and pathogenesis of recurrent vulvovaginal infections: a critical review

Recurrent vulvovaginal infections (RVVI) has not only become an epidemiological and clinical problem but also include large social and psychological consequences. Understanding the mechanisms of both commensalism and pathogenesis are necessary for the development of efficient diagnosis and treatment strategies for these enigmatic vaginal infections. Through this review, an attempt has been made to analyze vaginal microbiota (VMB) from scratch and to provide an update on its current understanding in relation to health and common RVVI i.e. bacterial vaginosis, vulvovaginal candidiaisis and Trichomoniasis, making the present review first of its kind. For this, potentially relevant studies were retrieved from data sources and critical analysis of the literature was made. Though, culture-independent methods have greatly unfolded the mystery regarding vaginal bacterial microbiome, there are only a few studies regarding the composition and diversity of vaginal mycobiome and different Trichomonas vaginalis strains. This scenario suggests a need of further studies based on comparative genomics of RVVI pathogens to improve our perceptive of RVVI pathogenesis that is still not clear (Fig. 5). Besides this, the review details the rationale for Lactobacilli dominance and changes that occur in healthy VMB throughout a women's life. Moreover, the list of possible agents continues to expand and new species recognised in both health and VVI are updated in this review. The review concludes with the controversies challenging the widely accepted dogma i.e. "VMB dominated with Lactobacilli is healthier than a diverse VMB". These controversies, over the past decade, have complicated the definition of vaginal health and vaginal infections with no definite conclusion. Thus, further studies on newly recognised microbial agents may reveal answers to these controversies. Conversely, VMB of women could be an answer but it is not enough to just look at the microbiology. We have to look at the woman itself, as VMB which is fine for one woman may be troublesome for others. These differences in women's response to the same VMB may be determined by a permutation of behavioural, cultural, genetic and various other anonymous factors, exploration of which may lead to proper definition of vaginal health and disease.

Fungal Symbionts Produce Prostaglandin E2 to Promote Their Intestinal Colonization

Candida albicans is a ubiquitous fungal symbiont that resides on diverse human barrier surfaces. Both mammalian and fungal cells can convert arachidonic acid into the lipid mediator, prostaglandin E2 (PGE2), but the physiological significance of fungus-derived PGE2 remains elusive. Here we report that a C. albicans mutant deficient in PGE2 production suffered a loss of competitive fitness in the murine gastrointestinal (GI) tract and that PGE2 supplementation mitigated this fitness defect. Impaired fungal PGE2 production affected neither the in vitro fitness of C. albicans nor hyphal morphogenesis and virulence in either systemic or mucosal infection models. Instead, fungal production of PGE2 was associated with enhanced fungal survival within phagocytes. Consequently, ablation of colonic phagocytes abrogated the intra-GI fitness boost conferred by fungal PGE2. These observations suggest that C. albicans has evolved the capacity to produce PGE2 from arachidonic acid, a host-derived precursor, to promote its own colonization of the host gut. Analogous mechanisms might undergird host-microbe interactions of other symbiont fungi.

Host-Pathogen Interactions Mediated by MDR Transporters in Fungi: As Pleiotropic as it Gets!

Fungal infections caused by Candida, Aspergillus, and Cryptococcus species are an increasing problem worldwide, associated with very high mortality rates. The successful prevalence of these human pathogens is due to their ability to thrive in stressful host niche colonization sites, to tolerate host immune system-induced stress, and to resist antifungal drugs. This review focuses on the key role played by multidrug resistance (MDR) transporters, belonging to the ATP-binding cassette (ABC), and the major facilitator superfamilies (MFS), in mediating fungal resistance to pathogenesis-related stresses. These clearly include the extrusion of antifungal drugs, with C. albicans CDR1 and MDR1 genes, and corresponding homologs in other fungal pathogens, playing a key role in this phenomenon. More recently, however, clues on the transcriptional regulation and physiological roles of MDR transporters, including the transport of lipids, ions, and small metabolites, have emerged, linking these transporters to important pathogenesis features, such as resistance to host niche environments, biofilm formation, immune system evasion, and virulence. The wider view of the activity of MDR transporters provided in this review highlights their relevance beyond drug resistance and the need to develop therapeutic strategies that successfully face the challenges posed by the pleiotropic nature of these transporters.

Lasioglossins LLIII affect the morphogenesis of Candida albicans and reduces the duration of experimental vaginal candidiasis in mice

Lasioglossins are a group of peptides with identified antimicrobial activity. The inhibitory effects of two synthetic lasioglossin derivatives, LLIII and D-isomeric variant LLIII-D, on morphological changes in Candida albicans in vitro and the effect of local administration of LLIII during experimental murine candidiasis were investigated. C. albicans blastoconidia were grown in the presence of lasioglossin LLIII or LLIII-D at concentrations of 11.5 μM and 21 μM, respectively, for 1, 2 and 3 days and their viability determined by flow cytometry using eosin Y staining. Morphological changes were examined by light and fluorescent microscopy. The Candida-inhibitory effect of daily intravaginal administration of 0.7 or 1.4 μg of LLIII was assessed in mice with experimentally-induced vaginal candidiasis. LLIII and LLIII-D lasioglossins exhibited candidacidal activity in vitro (>76% after 24 hr and >84% after 48 hr of incubation). After 72 hr incubation of Candida with low concentration of lasioglossins, an increase in viability was detected, probably due to a Candida antimicrobial peptides evasion strategy. Furthermore, lasioglossins inhibited temperature-induced morphotype changes toward hyphae and pseudohyphae with sporadic occurrence of atypical cells with two or enlarged nuclei, suggesting interference with mitosis or cytokinesis. Local application of LLIII reduced the duration of experimental candidiasis with no evidence of adverse effects. Lasioglossin LLIII is a promising candidate for development as an antimicrobial drug for treating the vaginal candidiasis.

Elevated nitric oxide in recurrent vulvovaginal candidiasis - association with clinical findings

INTRODUCTION

Recurrent vulvovaginal candidiasis is defined as having three to four episodes per year and causes substantial suffering. Little is known about the mechanisms leading to relapses in otherwise healthy women. Nitric oxide is part of the nonspecific host defense and is increased during inflammation. Nitric oxide levels were measured and the expression of inducible nitric oxide synthase was analyzed in the vagina during an acute episode of recurrent vulvovaginal candidiasis and after treatment with fluconazole.

MATERIAL AND METHODS

Twenty-eight women with symptoms of recurrent vulvovaginal candidiasis were enrolled together with 31 healthy controls. Nitric oxide was measured with an air-filled 25-mL silicon catheter balloon incubated in the vagina for five minutes and then analyzed by chemiluminescence technique. Vaginal biopsies were analyzed for the expression of inducible nitric oxide synthase. Symptoms and clinical findings were surveyed using a scoring system. The measurements and biopsies were repeated in patients after six weeks of fluconazole treatment.

RESULTS

Nitric oxide levels were increased during acute infection (median 352 ppb) compared with controls (median 6 ppb), p < 0.0001. The levels decreased after treatment (median 18 ppb) but were still higher than in controls. Increased expression of inducible nitric oxide synthase was observed in the epithelial basal layer in patients before and after treatment compared with controls. Before treatment, there were positive correlations between nitric oxide and symptom (r_s  = 0.644) and examination scores (r_s  = 0.677), p < 0.001.

CONCLUSIONS

Nitric oxide is significantly elevated in patients with recurrent vulvovaginal candidiasis during acute episodes of infection and decreases after antifungal treatment. The results illustrate the pronounced inflammatory response in recurrent vulvovaginal candidiasis correlating to symptoms of pain and discomfort.

The vaginal mycobiome: A contemporary perspective on fungi in women's health and diseases

Most of what is known about fungi in the human vagina has come from culture-based studies and phenotypic characterization of single organisms. Though valuable, these approaches have masked the complexity of fungal communities within the vagina. The vaginal mycobiome has become an emerging field of study as genomics tools are increasingly employed and we begin to appreciate the role these fungal communities play in human health and disease. Though vastly outnumbered by its bacterial counterparts, fungi are important constituents of the vaginal ecosystem in many healthy women. Candida albicans, an opportunistic fungal pathogen, colonizes 20% of women without causing any overt symptoms, yet it is one of the leading causes of infectious vaginitis. Understanding its mechanisms of commensalism and patho-genesis are both essential to developing more effective therapies. Describing the interactions between Candida, bacteria (such as Lactobacillus spp.) and other fungi in the vagina is funda-mental to our characterization of the vaginal mycobiome.

Inflammatory cervicovaginal cytology is associated with disease activity in juvenile systemic lupus erythematosus

To evaluate cervicovaginal cytology in adolescents with juvenile systemic lupus erythematosus (JSLE) and to compare them to controls. Fifty-two female adolescents with JSLE (ACR criteria) were compared to 52 age-matched healthy controls. All Pap smears were evaluated by the same cytopathologist blinded to gynecology examination (Bethesda 2001). The mean age of JSLE patients and controls were similar (16.17 ± 1.94 versus 16.13 ± 2.16 years, P = 0.92). The cervicovaginal cytology was found to be similar in both groups, although sexual intercourses in the last month were less frequent in JSLE than controls (23% versus 59.6%, P = 0.0003). Only one patient (2%) with JSLE versus two controls (4%) had cervical dysplasia (LGSIL) and human papilomavirus ( P = 1.0). Candida spp vaginitis was observed in seven JSLE (14%) versus none in controls ( P = 0.012) and was associated with immunosuppressive drugs ( P = 0.01) and high dose of prednisone ( P = 0.002). Of interest, inflammatory cervicovaginal cytology was observed in 21 (60%) of patients with SLEDAI ≥ 4 and only four (23%) of those with SLEDAI < 4 ( P = 0.001). Likewise, a higher frequency of inflammatory changes was also observed in virgin JSLE (57% versus 8%, P = 0.005). Our findings supports the notion that female genital tract may be a potential target organ in SLE since cervical inflammation is associated to disease activity independently of sexual activity. Lupus (2007) 16, 430—435.

Human Epithelial Cells Discriminate between Commensal and Pathogenic Interactions with Candida albicans

The commensal fungus, Candida albicans, can cause life-threatening infections in at risk individuals. C. albicans colonizes mucosal surfaces of most people, adhering to and interacting with epithelial cells. At low concentrations, C. albicans is not pathogenic nor does it cause epithelial cell damage in vitro; at high concentrations, C. albicans causes mucosal infections and kills epithelial cells in vitro. Here we show that while there are quantitative dose-dependent differences in exposed epithelial cell populations, these reflect a fundamental qualitative difference in host cell response to C. albicans. Using transcriptional profiling experiments and real time PCR, we found that wild-type C. albicans induce dose-dependent responses from a FaDu epithelial cell line. However, real time PCR and Western blot analysis using a high dose of various C. albicans strains demonstrated that these dose-dependent responses are associated with ability to promote host cell damage. Our studies support the idea that epithelial cells play a key role in the immune system by monitoring the microbial community at mucosal surfaces and initiating defensive responses when this community is dysfunctional. This places epithelial cells at a pivotal position in the interaction with C. albicans as epithelial cells themselves promote C. albicans stimulated damage.

Candida albicans-epithelial interactions and pathogenicity mechanisms: scratching the surface

Until recently, epithelial cells have been a largely ignored component of host responses to microbes. However, this has been largely overturned over the last decade as an ever increasing number of studies have highlighted the key role that these cells play in many of our interactions with our microbiota and pathogens. Interactions of these cells with Candida albicans have been shown to be critical not just in host responses, but also in fungal cell responses, regulating fungal morphology and gene expression profile. In this review, we will explore the interactions between C. albicans and epithelial cells, and discuss how these interactions affect our relationship with this fungus.

Vulvovaginal candidiasis: Epidemiology, microbiology and risk factors

Vulvovaginal candidiasis (VVC) is an infection caused by Candida species that affects millions of women every year. Although Candida albicans is the main cause of VVC, the identification of non-Candida albicans Candida (NCAC) species, especially Candida glabrata, as the cause of this infection, appears to be increasing. The development of VVC is usually attributed to the disturbance of the balance between Candida vaginal colonization and host environment by physiological or nonphysiological changes. Several host-related and behavioral risk factors have been proposed as predisposing factors for VVC. Host-related factors include pregnancy, hormone replacement, uncontrolled diabetes, immunosuppression, antibiotics, glucocorticoids use and genetic predispositions. Behavioral risk factors include use of oral contraceptives, intrauterine device, spermicides and condoms and some habits of hygiene, clothing and sexual practices. Despite a growing list of recognized risk factors, much remains to be elucidated as the role of host versus microorganisms, in inducing VVC and its recurrence. Thus, this review provides information about the current state of knowledge on the risk factors that predispose to VVC, also including a revision of the epidemiology and microbiology of VVC, as well as of Candida virulence factors associated with vaginal pathogenicity.

Pathogenic NLRP3 Inflammasome Activity during Candida Infection Is Negatively Regulated by IL-22 via Activation of NLRC4 and IL-1Ra

Candida albicans is a well-tolerated resident of human mucosal tissues. This implies that host defense mechanisms cooperate to limit inflammation while controlling fungal burden. The cytokine IL-22 and inflammasomes are essential components of the mucosal responses to C. albicans. How these components cooperate to mediate the balance of inflammation and host defense is not explored. We find that NLRP3 inflammasome activation promotes neutrophil recruitment and inflammation during infection and that this activity is counteracted by IL-22. Mechanistically, IL-22 activated NLRC4 for sustained production of the IL-1 receptor antagonist IL-1Ra, which restrained NLRP3 activity. Symptomatic infection in mice and humans occurred under conditions of IL-1Ra deficiency and was rescued in mice by replacement therapy with the recombinant IL-1Ra anakinra. Thus, pathogenic inflammasome activity during Candida infection is negatively regulated by the IL-22/NLRC4/IL-1Ra axis. Our findings offer insights into the pathogenesis of C. albicans and suggest therapeutic avenues for candidiasis.

Guideline: vulvovaginal candidosis (AWMF 015/072), S2k (excluding chronic mucocutaneous candidosis)

The oestrogenised vagina is colonised by Candida species in at least 20% of women; in late pregnancy and in immunosuppressed patients, this increases to at least 30%. In most cases, Candida albicans is involved. Host factors, particularly local defence mechanisms, gene polymorphisms, allergies, serum glucose levels, antibiotics, psycho-social stress and oestrogens influence the risk of candidal vulvovaginitis. Non-albicans species, particularly Candida glabrata, and in rare cases also Saccharomyces cerevisiae, cause less than 10% of all cases of vulvovaginitis with some regional variation; these are generally associated with milder signs and symptoms than normally seen with a C. albicans-associated vaginitis. Typical symptoms include premenstrual itching, burning, redness and odourless discharge. Although itching and redness of the introitus and vagina are typical symptoms, only 35-40% of women reporting genital itching in fact suffer from vulvovaginal candidosis. Medical history, clinical examination and microscopic examination of vaginal content using 400× optical magnification, or preferably phase contrast microscopy, are essential for diagnosis. In clinically and microscopically unclear cases and in chronically recurring cases, a fungal culture for pathogen determination should be performed. In the event of non-C. albicans species, the minimum inhibitory concentration (MIC) should also be determined. Chronic mucocutaneous candidosis, a rarer disorder which can occur in both sexes, has other causes and requires different diagnostic and treatment measures. Treatment with all antimycotic agents on the market (polyenes such as nystatin; imidazoles such as clotrimazole; and many others including ciclopirox olamine) is easy to administer in acute cases and is successful in more than 80% of cases. All vaginal preparations of polyenes, imidazoles and ciclopirox olamine and oral triazoles (fluconazole, itraconazole) are equally effective (Table ); however, oral triazoles should not be administered during pregnancy according to the manufacturers. C. glabrata is not sufficiently sensitive to the usual dosages of antimycotic agents approved for gynaecological use. In other countries, vaginal suppositories of boric acid (600 mg, 1-2 times daily for 14 days) or flucytosine are recommended. Boric acid treatment is not allowed in Germany and flucytosine is not available. Eight hundred-milligram oral fluconazole per day for 2-3 weeks is therefore recommended in Germany. Due to the clinical persistence of C. glabrata despite treatment with high-dose fluconazole, oral posaconazole and, more recently, echinocandins such as micafungin are under discussion; echinocandins are very expensive, are not approved for this indication and are not supported by clinical evidence of their efficacy. In cases of vulvovaginal candidosis, resistance to C. albicans does not play a significant role in the use of polyenes or azoles. Candida krusei is resistant to the triazoles, fluconazole and itraconazole. For this reason, local imidazole, ciclopirox olamine or nystatin should be used. There are no studies to support this recommendation, however. Side effects, toxicity, embryotoxicity and allergies are not clinically significant. Vaginal treatment with clotrimazole in the first trimester of a pregnancy reduces the rate of premature births. Although it is not necessary to treat a vaginal colonisation of Candida in healthy women, vaginal administration of antimycotics is often recommended in the third trimester of pregnancy in Germany to reduce the rate of oral thrush and napkin dermatitis in healthy full-term newborns. Chronic recurrent vulvovaginal candidosis continues to be treated in intervals using suppressive therapy as long as immunological treatments are not available. The relapse rate associated with weekly or monthly oral fluconazole treatment over 6 months is approximately 50% after the conclusion of suppressive therapy according to current studies. Good results have been achieved with a fluconazole regimen using an initial 200 mg fluconazole per day on 3 days in the first week and a dosage-reduced maintenance therapy with 200 mg once a month for 1 year when the patient is free of symptoms and fungal infection (Table ). Future studies should include Candida autovaccination, antibodies to Candida virulence factors and other immunological experiments. Probiotics with appropriate lactobacillus strains should also be examined in future studies on the basis of encouraging initial results. Because of the high rate of false indications, OTC treatment (self-treatment by the patient) should be discouraged.

Adaptive immune responses to Candida albicans infection

Fungal infections are becoming increasingly prevalent in the human population and contribute to morbidity and mortality in healthy and immunocompromised individuals respectively. Candida albicans is the most commonly encountered fungal pathogen of humans, and is frequently found on the mucosal surfaces of the body. Host defense against C. albicans is dependent upon a finely tuned implementation of innate and adaptive immune responses, enabling the host to neutralise the invading fungus. Central to this protection are the adaptive Th1 and Th17 cellular responses, which are considered paramount to successful immune defense against C. albicans infections, and enable tissue homeostasis to be maintained in the presence of colonising fungi. This review will highlight the recent advances in our understanding of adaptive immunity to Candida albicans infections.

Serum interleukin-6 levels in murine models of Candida albicans infection

Two Balb/C mouse models of Candida infection were used to detect serum interleukin-6 (IL-6) responses. The first model used systemic infection by Candida albicans ATCC 10231 strain infected through the lateral tail vein of mice without any specific pretreatment. The median Candida burdens of the kidneys were 1.5 × 106 CFU/ml 24 h postinoculation (p.i.) and 1.2 × 107 CFU/ml 72 h p.i., while median serum IL-6 levels were 479.3 pg/ml and 934.5 pg/ml, respectively. The Candida burden showed significant correlation with serum IL-6 24 h p.i. (R2 = 0.6358; P = 0.0082) but not 72 h p.i.The second model was a mouse vaginitis model applying intravaginal inoculation of mice pretreated with subcutaneous estradiol-valerate (10 mg/ml) 3 days before infection. Candida cell count in vaginal lavage fluid was 2.8 × 106 CFU/ml 24 h p.i. and 1.4 × 108 CFU/ml 72 h p.i. Serum IL-6 response was detected in 4 of 15 mice 24 h p.i. and 9 of 15 mice 72 h p.i. Even the responders had low IL-6 serum levels (mean values 29.9 pg/ml and 60.1 pg/ml, respectively) not correlating with Candida cell count in vaginal lavage fluid.In conclusion, serum IL-6 had strong relationship with systemic C. albicans infection while the local C. albicans infection of the vagina led to partial, prolonged and limited serum IL-6 response.

IL-22 and IDO1 affect immunity and tolerance to murine and human vaginal candidiasis

The ability to tolerate Candida albicans, a human commensal of the gastrointestinal tract and vagina, implicates that host defense mechanisms of resistance and tolerance cooperate to limit fungal burden and inflammation at the different body sites. We evaluated resistance and tolerance to the fungus in experimental and human vulvovaginal candidiasis (VVC) as well as in recurrent VVC (RVVC). Resistance and tolerance mechanisms were both activated in murine VVC, involving IL-22 and IL-10-producing regulatory T cells, respectively, with a major contribution by the enzyme indoleamine 2,3-dioxygenase 1 (IDO1). IDO1 was responsible for the production of tolerogenic kynurenines, such that replacement therapy with kynurenines restored immunoprotection to VVC. In humans, two functional genetic variants in IL22 and IDO1 genes were found to be associated with heightened resistance to RVVC, and they correlated with increased local expression of IL-22, IDO1 and kynurenines. Thus, IL-22 and IDO1 are crucial in balancing resistance with tolerance to Candida, their deficiencies are risk factors for RVVC, and targeting tolerance via therapeutic kynurenines may benefit patients with RVVC.

Guideline vulvovaginal candidosis (2010) of the German Society for Gynecology and Obstetrics, the Working Group for Infections and Infectimmunology in Gynecology and Obstetrics, the German Society of Dermatology, the Board of German Dermatologists and the German Speaking Mycological Society

Candida (C.) species colonize the estrogenized vagina in at least 20% of all women. This statistic rises to 30% in late pregnancy and in immunosuppressed patients. The most often occurring species is Candida albicans. Host factors, especially local defense deficiencies, gene polymorphisms, allergic factors, serum glucose levels, antibiotics, psychosocial stress and estrogens influence the risk for a Candida vulvovaginitis. In less than 10% of all cases, non-albicans species, especially C. glabrata, but in rare cases also Saccharomyces cerevisiae, cause a vulvovaginitis, often with fewer clinical signs and symptoms. Typical symptoms include premenstrual itching, burning, redness and non-odorous discharge. Although pruritus and inflammation of the vaginal introitus are typical symptoms, only less than 50% of women with genital pruritus suffer from a Candida vulvovaginitis. Diagnostic tools are anamnesis, evaluation of clinical signs, the microscopic investigation of the vaginal fluid by phase contrast (400 x), vaginal pH-value and, in clinically and microscopically uncertain or in recurrent cases, yeast culture with species determination. The success rate for treatment of acute vaginal candidosis is approximately 80%. Vaginal preparations containing polyenes, imidazoles and ciclopiroxolamine or oral triazoles, which are not allowed during pregnancy, are all equally effective. C. glabrata is resistant to the usual dosages of all local antimycotics. Therefore, vaginal boric acid suppositories or vaginal flucytosine are recommended, but not allowed or available in all countries. Therefore, high doses of 800 mg fluconazole/day for 2-3 weeks are recommended in Germany. Due to increasing resistence, oral posaconazole 2 × 400 mg/day plus local ciclopiroxolamine or nystatin for 15 days was discussed. C. krusei is resistant to triazoles. Side effects, toxicity, embryotoxicity and allergy are not clinically important. A vaginal clotrimazole treatment in the first trimester of pregnancy has shown to reduce the rate of preterm births in two studies. Resistance of C. albicans does not play a clinically important role in vulvovaginal candidosis. Although it is not necessary to treat vaginal candida colonization in healthy women, it is recommended in the third trimester of pregnancy in Germany, because the rate of oral thrush and diaper dermatitis in mature healthy newborns, induced by the colonization during vaginal delivery, is significantly reduced through prophylaxis. Chronic recurrent vulvovaginal candidosis requires a "chronic recurrent" suppression therapy, until immunological treatment becomes available. Weekly to monthly oral fluconazole regimes suppress relapses well, but cessation of therapy after 6 or 12 months leads to relapses in 50% of cases. Decreasing-dose maintenance regime of 200 mg fluconazole from an initial 3 times a week to once monthly (Donders 2008) leads to more acceptable results. Future studies should include candida autovaccination, antibodies against candida virulence factors and other immunological trials. Probiotics should also be considered in further studies. Over the counter (OTC) treatment must be reduced.

Candida albicans yeast and hyphae are discriminated by MAPK signaling in vaginal epithelial cells

We previously reported that a bi-phasic innate immune MAPK response, constituting activation of the mitogen-activated protein kinase (MAPK) phosphatase MKP1 and c-Fos transcription factor, discriminates between the yeast and hyphal forms of Candida albicans in oral epithelial cells (ECs). Since the vast majority of mucosal Candida infections are vaginal, we sought to determine whether a similar bi-phasic MAPK-based immune response was activated by C. albicans in vaginal ECs. Here, we demonstrate that vaginal ECs orchestrate an innate response to C. albicans via NF-κB and MAPK signaling pathways. However, unlike in oral ECs, the first MAPK response, defined by c-Jun transcription factor activation, is delayed until 2 h in vaginal ECs but is still independent of hypha formation. The 'second' or 'late' MAPK response, constituting MKP1 and c-Fos transcription factor activation, is identical to oral ECs and is dependent upon both hypha formation and fungal burdens. NF-κB activation is immediate but independent of morphology. Furthermore, the proinflammatory response in vaginal ECs is different to oral ECs, with an absence of G-CSF and CCL20 and low level IL-6 production. Therefore, differences exist in how C. albicans activates signaling mechanisms in oral and vaginal ECs; however, the activation of MAPK-based pathways that discriminate between yeast and hyphal forms is retained between these mucosal sites. We conclude that this MAPK-based signaling pathway is a common mechanism enabling different human epithelial tissues to orchestrate innate immune responses specifically against C. albicans hyphae.

Th17 cells and IL-17 in protective immunity to vaginal candidiasis

BACKGROUND

Th17 cells play a major role in coordinating the host defence in oropharyngeal candidiasis. In this study we investigated the involvement of the Th17 response in an animal model of vulvovaginal candidiasis (VVC).

METHODS

To monitor the course of infection we exploited a new in vivo imaging technique.

RESULTS

i) The progression of VVC leads to a strong influx of neutrophils in the vagina soon after the challenge which persisted despite the resolution of infection; ii) IL-17, produced by vaginal cells, particularly CD4 T cells, was detected in the vaginal wash during the infection, reaching a maximum 14 days after the challenge; iii) The amount and kinetics of IL-23 in vaginal fluids were comparable to those in vaginal cells; iv) The inhibition of Th17 differentiation led to significant inhibition of IL-17 production with consequent exacerbation of infection; v) An increased production of βdefensin 2 was manifested in cells of infected mice. This production was strongly reduced when Th17 differentiation was inhibited and was increased by rIL-17 treatment.

CONCLUSIONS

These results imply that IL-17 and Th17, along with innate antimicrobial factors, have a role in the immune response to vaginal candidiasis.

A beta-glucan-conjugate vaccine and anti-beta-glucan antibodies are effective against murine vaginal candidiasis as assessed by a novel in vivo imaging technique

The protective capacity of a parenterally administered beta-glucan-conjugate vaccine formulated with the human-compatible MF59 adjuvant was assessed in a murine model of vaginal candidiasis. To monitor infection, an in vivo imaging technique exploiting genetically engineered, luminescent Candida albicans was adopted, and compared with measurements of colony forming units. The vaccine conferred significant protection, and this was associated with production of serum and vaginal anti-beta-glucan IgG antibodies. Vaginal IgG molecules were the likely mediators of protection as inferred by the efficacy of passive transfer of immune vaginal fluid and passive protection by an anti-beta-1,3-glucan mAb. Overall, the in vivo imaging technique was more reliable than vaginal CFU counts in assessing the extent and duration of the vaginal infection, and the consequent protection level.

Correlation between HIV and sexual behavior, drug use, trichomoniasis and candidiasis among female sex workers in a Mekong Delta province of Vietnam

To determine the prevalence of HIV and correlates of HIV infection among female sex workers (FSWs) in Soc Trang province, Vietnam, a survey of 406 FSWs in Soc Trang province was conducted between May and August, 2003. The participants were interviewed, using a standardized interview, to obtain information about socio-demographic and behavioral characteristics, and gynecologic and sexually transmitted infection (STI) history. The prevalence of HIV was 3.3%. An increased risk for HIV was associated with ever using illicit drugs, direct sex work, early sexual debut, age of FSWs, and infection with candidiasis and trichomoniasis. Reduced likelihood of HIV was only associated with withdrawal as a contraceptive method. A strong association of HIV with drug use and candidiasis and trichomoniasis infection among FSWs was found. Needle/syringe exchange, STI treatment, and methadone programs targeting FSWs should be implemented, and should include 100% condom use promotion.

Fenticonazole activity measured by the methods of the European Committee on Antimicrobial Susceptibility Testing and CLSI against 260 Candida vulvovaginitis isolates from two European regions and annotations on the prevalent genotypes

The activity of fenticonazole was studied against 260 West and Southeast European vulvovaginal candidiasis isolates, and low MICs were displayed. Fenticonazole was assessed by European Committee on Antimicrobial Susceptibility Testing and CLSI microdilution methods for the first time, and the results showed excellent agreement (97%) and significant interclass correlation coefficient (P < 0.0001). Also, the levels of agreement for the results for itraconazole, fluconazole, and ketoconazole were 84%, 90%, and 98% (P < 0.0001), respectively. Multilocus typing by PCR fingerprinting and subsequent cluster analysis delineated geographically associated alignments for Candida albicans and fluconazole resistance-related clusters for Candida glabrata.

Epidemiological phenotypic characteristics of vaginal yeasts at the Comoros

The aim of the prospective, descriptive survey conducted in Moroni, Comoros was to establish the distribution of vulvovaginal mycoses in pregnant and symptomatic women and to study the epidemiological characteristics of the yeast isolates. All isolated strains were epidemiologically evaluated by phenotypical methods. Three phenotypic epidemiological studies were performed by morphotyping methods (including the colour reaction according to Quindòs et al. and structural morphotypes as described by Soll), by determination of phospholipase and by chemosensitivity evaluation according to the Clinical and Laboratory Standards Institute approved standard. Out of 253 women, 108 were found positive for yeast culture (42.7%). Fungal identification results showed that 61.6% was Candida albicans and 28.6%C. sake (32/112). Candida sake was a frequent vaginal inhabitant.

C. albicans colonization of human mucosal surfaces

BACKGROUND

Candida albicans is a low level commensal organism in normal human populations with the continuous potential to expand and cause a spectrum of clinical conditions.

METHODOLOGY/PRINCIPAL FINDINGS

Using ex vivo human organ cultures and populations of primary human cells, we have developed several related experimental systems to examine early-stage interactions between C. albicans and mucosal surfaces. Experiments have been conducted both with exogenously added C. albicans and with overtly normal human mucosal surfaces supporting pre-existing infections with natural isolates of Candida. Under different culture conditions, we have demonstrated the formation of C. albicans colonies on human target cells and filament formation, equivalent to tissue invasion.

CONCLUSIONS/SIGNIFICANCE

These organ culture systems provide a valuable new resource to examine the molecular and cellular basis for Candida colonization of human mucosal surfaces.

The case for extrathymic development of vaginal T lymphocytes

The vaginal tract mucosa is populated by a small, yet phenotypically diverse and functionally significant, subset of T cells that plays a major role in local cell-mediated immunity. Although phenotypic and functional characteristics of vaginal T cells have received some attention in recent years, little is known about the development of this cell population. In this mini review, the developmental origins of vaginal T cells are traced from published work related to vaginal T cells, the vaginal mucosa environment and vaginal tract infection animal models. A CD3(+)TCR(+)CD2(+)CD5(+)B220(-) (CD3(+)B220(-)) subpopulation, which is mostly CD4(+), makes up 30-40% of vaginal T lymphocytes. This population consists of a TCRalphabeta(+) subset and TCRgammadelta(+) subset. While CD3(+)B220(-)TCRalphabeta(+) vaginal T cells exhibit phenotypic and functional properties consistent with that of peripheral T cells, CD3(+)B220(-)TCRgammadelta(+) vaginal T cells exhibit unique phenotypic and functional features that set them apart from other TCRgammadelta(+) T cell subsets populating the periphery or other mucosal areas. The vaginal mucosa is populated also by CD3(+)TCRalphabeta(+)CD4(-)/8(-)B220(+)CD2(-)CD5(-) T cells (CD3(+)B220(+)) whose relative predominance increases significantly in systemic T cell deficiency. This subset is generally unresponsive to TCR-mediated stimuli and expresses high levels of CD25, perhaps indicative of a regulatory role. Current data suggest that, while CD3(+)B220(-) vaginal T cells are mostly thymic in origin, CD3(+)TCRalphabeta(+)B220(+) cells are exclusively extrathymic.

Systemic and mucosal immunization with Candida albicans hsp90 elicits hsp90-specific humoral response in vaginal mucosa which is further enhanced during experimental vaginal candidiasis

The Candida albicans heat shock protein 90 kDa (hsp90-CA) is an important target for protective antibodies in disseminated candidiasis of experimental mice and humans. Hsp90-CA is present in the cell wall of Candida pseudohyphae or hyphae--typical pathogenic morphotypes in both mucosal and systemic Candida infections. However, the potential protective effects of hsp90-CA-specific antibodies in vaginal candidiasis has not yet been reported. In the present study we used various vaccine formulations (recombinant hsp90-CA protein and hsp90-CA-encoding DNA vaccine) and routes of administration (intradermal, intranasal, and intravenous) to induce both hsp90-CA-specific systemic and vaginal mucosa immune responses in experimental BALB/c mice. The results showed that intradermal recombinant hsp90-CA protein priming, followed by intranasal or intradermal recombinant hsp90-CA protein boosting induced significant increases in both serum and vaginal hsp90-CA-specific IgG and IgA antibodies compared to the control group, as well as enhanced hsp90-CA-specific splenocyte responses in vitro. In the intradermally boosted group, subsequent experimental vaginal Candida infection induced additional increases in the hsp90-CA specific IgG isotype, suggesting that Candida has the ability to induce a local hsp90-specific antibody (IgG) response during vulvovaginal candidiasis. Further work is required to elucidate the importance of immunity to highly conserved antigens during infection of the human female reproductive tract where a balance between immunity to and tolerance for commonly antigens such as hsp90 is necessary for the maintenance of fertility.

Candidiasis--do we need to fight or to tolerate the Candida fungus?

Candidiases, infections caused by germination forms of the Candida fungus, represent a heterogeneous group of diseases from systemic infection, through mucocutaneous form, to vulvovaginal form. Although caused by one organism, each form is controlled by distinct host immune mechanisms. Phagocytosis by polymorphonuclears and macrophages is generally accepted as the host immune mechanism for Candida elimination. Phagocytes require proinflammatory cytokine stimulation which could be harmful and must be regulated during the course of infection by the activity of CD8+ and CD4+ T cells. In the vaginal tissue the phagocytes are inefficient and inflammation is generally an unwanted reaction because it could damage mucosal tissue and break the tolerance to common vagina antigens including the otherwise saprophyting Candida yeast. Recurrent form of vulvovaginal candidiasis is probably associated with breaking of such tolerance. Beside the phagocytosis, specific antibodies, complement, and mucosal epithelial cell comprise Candida eliminating immune mechanisms. They are regulated by CD4+ and CD8+ T cells which produce cytokines IL-12, IFN-gamma, IL-10, TGF-beta, etc. as the response to signals from dendritic cells specialized to sense actual Candida morphotypes. During the course of Candida infection proinflammatory signals (if initially necessary) are replaced successively by antiinflammatory signals. This balance is absolutely distinct during each candidiasis form and it is crucial to describe and understand the basic principles before designing new therapeutic and/or preventive approaches.

Vulvovaginal candidosis

Despite therapeutic advances, vulvovaginal candidosis remains a common problem worldwide, affecting all strata of society. Understanding of anti-candida host defence mechanisms in the vagina has developed slowly and, despite a growing list of recognised risk factors, a fundamental grasp of pathogenic mechanisms continues to elude us. The absence of rapid, simple, and inexpensive diagnostic tests continues to result in both overdiagnosis and underdiagnosis of vulvovaginal candidosis. I review the epidemiology and pathogenesis of this infection, and also discuss management strategies.

Glucose in vaginal secretions before and after oral glucose tolerance testing in women with and without recurrent vulvovaginal candidiasis

OBJECTIVE

To measure the change of glucose in vaginal secretions during glucose tolerance testing in women with recurrent vulvovaginal candidiasis and in healthy control subjects.

METHODS

Thirty-eight women with recurrent vulvovaginal candidiasis and 45 healthy, age-matched controls completed a health questionnaire regarding general and gynecologic health and food and alcohol habits. They all underwent an oral glucose tolerance test and a vaginal examination. Vaginal secretion was collected from the proximal part of the vagina. Glucose in plasma and in vaginal secretions were measured at fasting and after 2 hours and analyzed with the hexokinase method. A sample size analysis showed that the number of subjects included in the study was sufficient for a beta value of 0.80, at the significance level of alpha=.05, at a difference in glucose in vaginal secretions of 30% after oral glucose tolerance test.

RESULTS

In healthy women, the median level of glucose in vaginal secretions was 5.2 mM before and 3.7 mM after oral glucose tolerance test, and plasma glucose was 5.0 mM before and 5.8 mM after oral glucose tolerance test. No significant difference was seen regarding change of glucose level in vaginal secretions and plasma glucose after testing, compared with before oral glucose tolerance testing.

CONCLUSION

There were no differences between women with recurrent vulvovaginal candidiasis and control subjects regarding change in glucose level in vaginal secretions or in plasma during oral glucose tolerance test.

LEVEL OF EVIDENCE

II-2.

Polysaccharide-containing conjugate vaccines for fungal diseases

The recognition that antibodies are effective against fungal pathogens has spawned interest in developing vaccines that elicit antibody-mediated protection. Recently, a novel polysaccharide-protein conjugate vaccine that uses the algal antigen laminarin was shown to elicit antibodies to beta-glucan in fungal cell walls and to mediate protection against both experimental candidiasis and aspergillosis. Remarkably, vaccine-induced antibodies manifested direct antifungal effects, suggesting that vaccine efficacy might not require cellular or other components of the immune system. The description of a vaccine that could protect against various fungal pathogens opens exciting new dimensions in the search for approaches to control fungal diseases.

Her choice: Dealing with lactobacilli, vaginitis, and antibiotics

Vulvovaginal candidiasis is a common problem for women, yet there are many gaps in knowledge about candida's pathogenesis, immunity, and its reputed association with antibiotic use. Women often self-diagnose and self-manage the problem, yet one of the most common folk remedies used, the probiotic lactobacillus, has no biologically plausible mechanism to explain any beneficial actions and no rigorous evidence to support its effectiveness. This paper explores these issues and summaries potential areas for further research.