Patients with STAT1 Gain-of-function Mutations Display Increased Apoptosis which is Reversed by the JAK Inhibitor Ruxolitinib.

INTRODUCTION: The signal transducer and activator of transcription (STAT1) gain-of-function (GOF) syndrome accounts for most cases of chronic mucocutaneous candidiasis but is characterized by a broader clinical phenotype that may include bacterial, viral, or invasive fungal infections, autoimmunity, autoinflammatory manifestations, vascular complications, or malignancies. The severity of lymphopenia may vary and influence the infectious morbidity. METHODS: In our cohort of seven STAT1-GOF patients, we investigated the mechanisms that may determine T lymphopenia, we characterized the interferon gene signature (IGS) and analyzed the effect of ruxolitinib in reverting the immune dysregulation. RESULTS: STAT1-GOF patients exhibited increased T lymphocyte apoptosis that was significantly augmented in both resting conditions and following stimulation with mitogens and IFNα, as evaluated by flow cytometry by Annexin V/ Propidium iodide assay. The JAK inhibitor ruxolitinib significantly reduced the IFNα-induced hyperphosphorylation of STAT1 and reverted the stimulation-induced T-cell apoptosis, in vitro. In two adult STAT1-GOF patients, the JAKinib treatment ameliorated chronic mucocutaneous candidiasis and lymphopenia. Most STAT1-GOF patients, particularly those who had autoimmunity, presented increased IGS that significantly decreased in the two patients during ruxolitinib treatment. CONCLUSION: In STAT1-GOF patients, T lymphocyte apoptosis is increased, and T lymphopenia may determine higher risk of severe infections. The JAKinib target therapy should be evaluated to treat severe chronic candidiasis and lymphopenia, and to downregulate the IFNs in patients with autoinflammatory or autoimmune manifestations.

Patients with recurrent vulvovaginal candidiasis exhibit a decrease in both the fungicidal activity of neutrophils and the proliferation of peripheral blood mononuclear cells.

BACKGROUND: Recurrent vulvovaginal candidiasis (RVVC) is an important and underestimated fungal infection. OBJECTIVE: We aimed to determine the fungicidal and proliferative capacities of neutrophils and peripheral blood mononuclear cells (PBMCs), respectively and the clinical and microbiological characteristics of a cohort of Colombian patients diagnosed with RVVC. METHODS: A cross-sectional study was conducted. A total of 66 women were included (40 diagnosed with RVVC and 26 healthy women [HW]). Demographic and clinical data were recorded. Vaginal fluid samples were obtained for isolation, identification and antifungal susceptibility testing of Candida species using selective culture media and the Vitek 2.0® system. Blood samples were also obtained to evaluate cell subpopulations; furthermore, neutrophils and PBMCs were isolated to determine their fungicidal and proliferative capacities, respectively. RESULTS: The median age was 29 (IQR: 34-23) for RVVC and 24 (IQR: 30-23) for HW. Only two species of the genus Candida were identified: Candida albicans (92.5%) and Candida lusitaniae (7.5%). Resistance to fluconazole, voriconazole, flucytosine and amphotericin B was observed on six C. albicans isolates and one C. lusitaniae isolate. Only the family history of vulvovaginal candidiasis was associated with RVVC occurrence. The RVVC group exhibited a significantly higher number of neutrophils but with lower fungicidal activity in comparison to HW; likewise, PBMCs from RVVC patients presented a lower proliferation index when stimulated with C. albicans. CONCLUSION: Contrary to what has been reported worldwide, in Colombian patients with RVVC, C. albicans was the main isolated species without increased antifungal resistance. The diminished fungicidal and proliferative capacities of neutrophils and PBMCs, respectively, could suggest a possible alteration in the innate and adaptive immune responses.

CARD9 mutations in patients with fungal infections: An update from the last 5 years.

BACKGROUND: Autosomal recessive deficiency in the caspase recruitment domain-containing protein 9 (CARD9) is a congenital immunological condition that leads to susceptibility to mucocutaneous and invasive fungal infections. There is growing incidence of fungal infections in patients with CARD9 deficiency, a phenomenon that is increasingly recognised. OBJECTIVES: This study aimed to assess the frequency, geographic distribution and nature of mutations in patients with CARD9 deficiency, based on published papers in the literature until March 2023. METHODS: We swiftly conducted a study to pinpoint every documented instance of fungal infections arising from CARD9 deficiency. We selected case reports from the databases of PubMed, Embase, Scopus and Google Scholar spanning the period from October 2009 to March 2023. RESULTS: We analysed 90 cases of fungal infections and identified 32 mutations in the CARD9 gene. Notably, the homozygous (HMZ) p.Q295X (c.883C > T) mutation was associated with an increased risk of candidiasis. In contrast, the HMZ p.Q289X (c.865C > T) mutation is linked to a higher risk of dermatophytosis. We observed differences in the geographical distribution of these mutations. The primary mutations found in African patients differ from those in Asian patients. Specifically, Asian patients exhibit a broader spectrum of CARD9 mutations than African patients. CONCLUSIONS: The diversity of mutations observed in the 90 cases revealed 32 distinct variations, emphasising the unique genetic alterations in the CARD9 gene associated with specific geographical areas and the corresponding prevalence of fungal infections.

Progress in molecular diagnosis and treatment of chronic mucocutaneous candidiasis.

Chronic mucocutaneous candidiasis (CMC) is characterized by recurrent or persistent infections with Candida of the skin, nails, and mucous membrane. It is a rare and severe disease resulting from autoimmune defects or immune dysregulations. Nonetheless, the diagnosis and treatment of CMC still pose significant challenges. Erroneous or delayed diagnoses remain prevalent, while the long-term utility of traditional antifungals often elicits adverse reactions and promotes the development of acquired resistance. Furthermore, disease relapse can occur during treatment with traditional antifungals. In this review, we delineate the advancements in molecular diagnostic and therapeutic approaches to CMC. Genetic and biomolecular analyses are increasingly employed as adjuncts to clinical manifestations and fungal examinations for accurate diagnosis. Simultaneously, a range of therapeutic interventions, including Janus kinase (JAK) inhibitors, hematopoietic stem cell transplantation (HSCT), cytokines therapy, novel antifungal agents, and histone deacetylase (HDAC) inhibitors, have been integrated into clinical practice. We aim to explore insights into early confirmation of CMC as well as novel therapeutic options for these patients.

Isolated Cutaneous Granuloma Caused by Candida Parapsilosis: Case Report and Literature Review.

Candidal granuloma is an uncommon type of deep chronic cutaneous candidiasis. Candida albican is the most common causative pathogen for candidal granuloma. We report herein the original case of a 69-year-old Chinese woman presented with a 3-year of painful cutaneous lesion on the back of left hand. Physical examination revealed a 4 × 5 cm large infiltrative reddish plaque with unclear boundaries. The yellow-white crusts were observed on the uneven surface of plaque. Histopathological examination of biopsy tissue revealed that yeast cells and the horizontal section of hyphae in the dermis by hematoxylin eosin staining and periodic acid-Schiff staining. Finally, the pathogen was identified as Candida parapsilosis by mycological examination and molecular identification. The patient was treated with itraconazole oral 200 mg twice daily combined with topical terbinafine hydrochloride cream for 2 months. The lesions were fully resolved and no recurrence was observed. Since the cutaneous infection caused by C. parasilosis were rarely reported, we also reviewed all 11 cases of cutaneous infection caused by C. parapsilosis in the PubMed. Our study highlighted that chronic unilateral infiltrated plaques or ulcers should be aware of the occurrence of fungal granuloma including candidal granuloma especially in immunocompromised patients.

Deep dermatophytosis caused by Trichophyton rubrum in an elderly patient with CARD9 deficiency: A case report and literature review.

Deep dermatophytosis is an invasive and sometimes life-threatening fungal infection mainly reported in immunocompromised patients. However, a caspase recruitment domain-containing protein 9 (CARD9) deficiency has recently been reported to cause deep dermatophytosis. Herein, we report the first Japanese case of deep dermatophytosis associated with CARD9 deficiency. An 80-year-old Japanese man with tinea corporis presented with subcutaneous nodules on his left sole. Histopathological findings revealed marked epithelioid cell granulomas with filamentous fungal structures in the deep dermis and subcutis, and the patient was diagnosed with deep dermatophytosis. Despite antifungal therapy, the subcutaneous nodule on his left sole gradually enlarged, his left calcaneal bone was invaded, and the patient finally underwent amputation of his left leg. Genetic analysis revealed a homozygous CARD9 c.586 A > G (p. Lys196Glu) variant, suggesting a CARD9 deficiency. Here, we discuss the clinical features of CARD9 deficiency-associated deep dermatophytosis with a case report and review of the literature.

Innate Error Immunities of the Th17 Immune Pathway Associated With Chronic Mucocutaneous Candidiasis: A Systematic Review.

BACKGROUND: Candida albicans is an opportunistic pathogenic yeast commensal in human mucosa. In individuals with compromised immune systems, it can present as chronic mucocutaneous candidiasis (CMC) or systemic infection. CMC often exists in the presence of other infectious phenotypes due to dysfunction of the Th17 immune response. OBJECTIVE: To examine innate error immunities (IEI) of the Th17 immune response associated with CMC. METHODS: MEDLINE PubMed, Embase, and Web of Science were searched for keywords and Medical Subject Headings (MeSH) related to the subject of interest. Nonapplicable and non-primary research methodologies were excluded. RESULTS: We identified 266 articles; 89 were removed for being a duplicate, 108 for irrelevance, and 51 for being a review. We examined 18 studies, 5 on murine models, and 13 human studies. CONCLUSION: Case reports in patients with CMC have identified a range of mutations in IL-17F, IL-17RA, IL-17RC, and ACT1. Mouse models confirm the role of IL-17A and IL-17F in disease susceptibility. J Drugs Dermatol. 2023;22(12):1197-1203. doi:10.36849/JDD.7579.

Novel STAT1 mutation in a paediatric case of chronic mucocutaneous candidiasis complicated by primary hypothyroidism: clinical presentation, genetic analysis and prognostic implications.

This case report presents a young girl in her early childhood diagnosed with chronic mucocutaneous candidiasis (CMC) and primary hypothyroidism. Genetic analysis revealed a novel de novo mutation in the STAT1 gene (exon 11, c.972C>G, p.Cys324Trp), adding to the existing literature on STAT1 mutations, which account for approximately 53% of CMC cases. The identified mutation is predicted to have a more severe pathogenic impact based on PolyPhen-2 scoring. Our findings emphasise the importance of comprehensive genetic testing in CMC diagnosis and suggest that the specific mutation site may correlate with disease prognosis. The case underscores the need for vigilant monitoring and targeted therapeutic interventions, given the potential for poorer outcomes.

Isolated Chronic Mucocutaneous Candidiasis due to a Novel Duplication Variant of IL17RC.

PURPOSE: Inborn errors of the IL-17A/F-responsive pathway lead to chronic mucocutaneous candidiasis (CMC) as a predominant clinical phenotype, without other significant clinical manifestations apart from mucocutaneous staphylococcal diseases. Among inborn errors affecting IL-17-dependent immunity, autosomal recessive (AR) IL-17RC deficiency is a rare disease with only three kindreds described to date. The lack of an in vitro functional evaluation system of IL17RC variants renders its diagnosis difficult. We sought to characterize a 7-year-old Japanese girl with CMC carrying a novel homozygous duplication variant of IL17RC and establish a simple in vitro system to evaluate the impact of this variant. METHODS: Flow cytometry, qPCR, RNA-sequencing, and immunoblotting were conducted, and an IL17RC-knockout cell line was established for functional evaluation. RESULTS: The patient presented with oral and mucocutaneous candidiasis without staphylococcal diseases since the age of 3 months. Genetic analysis showed that the novel duplication variant (Chr3: 9,971,476-9,971,606 dup (+131bp)) involving exon 13 of IL17RC results in a premature stop codon (p.D457Afs*16 or p.D457Afs*17). Our functional evaluation system revealed this duplication to be loss-of-function and enabled discrimination between loss-of-function and neutral IL17RC variants. The lack of response to IL-17A by the patient's SV40-immortalized fibroblasts was restored by introducing WT-IL17RC, suggesting that the genotype identified is responsible for her clinical phenotype. CONCLUSIONS: The clinical and cellular phenotype of the current case of AR IL-17RC deficiency supports a previous report on this rare disorder. Our newly established evaluation system will be useful for the diagnosis of AR IL-17RC deficiency, providing accurate validation of unknown IL17RC variants.

Neutrophils in STAT1 Gain-Of-Function Have a Pro-inflammatory Signature Which Is Not Rescued by JAK Inhibition.

STAT1 gain-of-function (GOF) mutations cause an inborn error of immunity with diverse phenotype ranging from chronic mucocutaneous candidiasis (CMC) to various non-infectious manifestations, the most precarious of which are autoimmunity and vascular complications. The pathogenesis centers around Th17 failure but is far from being understood. We hypothesized that neutrophils, whose functions have not been explored in the context of STAT1 GOF CMC yet, might be involved in the associated immunodysregulatory and vascular pathology. In a cohort of ten patients, we demonstrate that STAT1 GOF human ex-vivo peripheral blood neutrophils are immature and highly activated; have strong propensity for degranulation, NETosis, and platelet-neutrophil aggregation; and display marked inflammatory bias. STAT1 GOF neutrophils exhibit increased basal STAT1 phosphorylation and expression of IFN stimulated genes, but contrary to other immune cells, STAT1 GOF neutrophils do not display hyperphosphorylation of STAT1 molecule upon stimulation with IFNs. The patient treatment with JAKinib ruxolitinib does not ameliorate the observed neutrophil aberrations. To our knowledge, this is the first work describing features of peripheral neutrophils in STAT1 GOF CMC. The presented data suggest that neutrophils may contribute to the immune pathophysiology of the STAT1 GOF CMC.

Quality of life in women with chronic recurrent vulvovaginal candidosis: A sub-analysis of the prospective multicentre phase IIb/III Prof-001 study.

BACKGROUND: Chronic recurrent vulvovaginal candidosis (RVVC), defined as three or more episodes of vulvovaginal candidosis per year, significantly impairs quality of life (QoL) and sexual health. OBJECTIVES: The primary objective of this study was to assess health-related QoL in women with RVVC using validated questionnaires before and after treatment. The secondary objective was to analyse the effect of RVVC on women's sexual health. PATIENTS/METHODS: This was a sub-analysis of a randomised, controlled, double-blinded study titled 'A phase IIb/III, parallel-arm, randomized, active-controlled, double-blind, double-dummy, multicenter, non-inferiority study in patients with recurrent vulvovaginal candidosis to compare the clinical efficacy, safety and tolerability of topically administered ProF-001 (Candiplus®) to oral fluconazole, which was conducted at 35 study sites in Austria, Poland and Slovakia. QoL was assessed using the European Quality of Life (EQ) five-dimension five-level scale (EQ-5D-5L) and visual analogue scale (EQ-VAS) questionnaires, followed by specific questions regarding sexuality. RESULTS: From 2019 to 2021, 360 of 432 (83.3%) women with RVVC had accomplished a 6-months maintenance treatment and were enrolled in this sub-analysis. The EQ-5D-5L and EQ-VAS scores demonstrated improved QoL in 137 (65.2%) and 159 (75.4%) women after 6 months of maintenance treatment. Each individual aspect of sexual health significantly improved (all p < .05). A reduction in pain frequency during or after sexual intercourse in the 6-month period occurred in 124 (66.3%) women. CONCLUSIONS: Women with RVVC had high QoL and sexual health impairment; however, a 6-months maintenance treatment resulted in effective improvement in QoL and sexual health.

Oral candidiasis and seborrheic dermatitis in an 8-year-old female with a heterozygous variant of the IL-17RC gene.

An 8-year-old female with chronic oral candidiasis and severe seborrheic dermatitis was found to have a heterozygous mutation (p.R14X c.40 C>T) of the IL-17RC gene, which was predicted to possibly represent a new pathogenic variant via truncation or nonsense-mediated mRNA decay. Given previously reported IL-17RC-related disorders are autosomal recessive, we would expect an affected individual to have two mutated alleles whereas our patient was heterozygous. Given the overlapping clinical picture, this variant could be responsible for altered immunity against both Candida and Malassezia species. This is the first report to our knowledge of chronic oral candidiasis and severe seborrheic dermatitis in a patient with a heterozygous variant (p.R14X c.40 C>T) for the IL-17RC gene.

Case report: Myocarditis in congenital STAT1 gain-of function.

Autosomal dominant Signal transducer and activator of transcription 1 (STAT1) gain-of-function (GOF) mutations result in an inborn error of immunity characterized by chronic mucocutaneous candidiasis, recurrent viral and bacterial infections, and diverse autoimmune manifestations. Current treatment consists of chronic antifungal therapy, antibiotics for concomitant infections, and immunosuppressive therapy in case of autoimmune diseases. More recently, treatment with Janus kinases 1 and 2 (JAK1/2) inhibitors have shown promising yet variable results. We describe a STAT1 GOF patient with an incidental finding of elevated cardiac troponins, leading to a diagnosis of a longstanding, slowly progressive idiopathic myocarditis, attributed to STAT1 GOF. Treatment with a JAK-inhibitor (baricitinib) mitigated cardiac inflammation on MRI but was unable to alter fibrosis, possibly due to the diagnostic and therapeutic delay, which finally led to fatal arrhythmia. Our case illustrates that myocarditis could be part of the heterogeneous disease spectrum of STAT1 GOF. Given the insidious presentation in our case, a low threshold for cardiac evaluation in STAT1 GOF patients seems warranted.

The Th17/IL-17 Axis and Host Defense Against Fungal Infections.

Chronic mucocutaneous candidiasis (CMC) was recognized as a primary immunodeficiency in the early 1970s. However, for almost 40 years, its genetic etiology remained unknown. The progressive molecular and cellular description of inborn errors of immunity (IEI) with syndromic CMC pointed toward a possible role of IL-17-mediated immunity in protecting against fungal infection and CMC. Since 2011, novel IEI affecting either the response to or production of IL-17A and/or IL-17F (IL-17A/F) in patients with isolated or syndromic CMC provided formal proof of the pivotal role of the IL-17 axis in mucocutaneous immunity to Candida spp, and, to a lesser extent, to Staphylococcus aureus in humans. In contrast, IL-17-mediated immunity seems largely redundant against other common microbes in humans. In this review, we outline the current knowledge of IEI associated with impaired IL-17A/F-mediated immunity, highlighting our current understanding of the role of IL-17A/F in human immunity.