Case Report: A New Gain-of-Function Mutation of STAT1 Identified in a Patient With Chronic Mucocutaneous Candidiasis and Rosacea-Like Demodicosis: An Emerging Association

"Demodicosis" Mimicking PreSeptal Cellulitis: Severe Periocular and Facial Inflammation Caused by "Normal" Skin Flora

Due to their relatively high prevalence and commensalism, the pathogenicity of Demodex mites has been debated. Recent data, however, show Demodex to be associated with skin and ocular surface diseases such as rosacea, blepharitis, and keratitis. Here the authors report the first known case, to the best of the their knowledge, of Demodex infestation mimicking preseptal cellulitis in an adult human. A 29-year-old male bilaterally blind from advanced retinopathy of prematurity presented with a 2-month history of right-greater-than-left upper eyelid and periocular/cheek swelling, redness, and ocular discharge that did not resolve with oral antibiotics or oral steroids. Based on MRI findings, biopsies of the right lacrimal gland, right orbital fat, and right upper eyelid preseptal skin were obtained which revealed marked intrafollicular Demodex mite density and budding yeasts in the upper eyelid skin. This case serves to alert clinicians to this entity that may not otherwise be usually considered in ophthalmic clinical practice.

Granulomatous rosacea: a clue to the diagnosis of STAT1 gain of function in a child with immunodeficiency

Recurrent granulomatous rosacea in a paediatric patient prompted an investigation that unveiled a rare gain-of-function mutation in the STAT1 gene. This case highlights the clinical diversity associated with STAT1 mutations and underscores the importance of considering genetic factors in unexplained immunodeficiency and skin conditions, offering valuable insights for diagnosis and treatment.

Human STAT1 gain of function with chronic mucocutaneous candidiasis: A comprehensive review for strengthening the connection between bedside observations and laboratory research

Germline human heterozygous STAT1 gain-of-function (GOF) variants were first discovered a common cause of chronic mucocutaneous candidiasis (CMC) in 2011. Since then, numerous STAT1 GOF variants have been identified. A variety of clinical phenotypes, including fungal, viral, and bacterial infections, endocrine disorders, autoimmunity, malignancy, and aneurysms, have recently been revealed for STAT1 GOF variants, which has led to the expansion of the clinical spectrum associated with STAT1 GOF. Among this broad range of complications, it has been determined that invasive infections, aneurysms, and malignancies are poor prognostic factors for STAT1 GOF. The effectiveness of JAK inhibitors as a therapeutic option has been established, although further investigation of their long-term utility and side effects is needed. In contrast to the advancements in treatment options, the precise molecular mechanism underlying STAT1 GOF remains undetermined. Two primary hypotheses for this mechanism involve impaired STAT1 dephosphorylation and increased STAT1 protein levels, both of which are still controversial. A precise understanding of the molecular mechanism is essential for not only advancing diagnostics but also developing therapeutic interventions. Here, we provide a comprehensive review of STAT1 GOF with the aim of establishing a stronger connection between bedside observations and laboratory research.

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.

Genetics of infertility: a paradigm shift for medically assisted reproduction

The field of reproductive genetics has undergone significant advancements with the completion of the Human Genome Project and the development of high-throughput sequencing techniques. This has led to the identification of numerous genes involved in both male and female infertility, revolutionizing the diagnosis and management of infertility patients. Genetic investigations, including karyotyping, specific genetic tests, and high-throughput sequencing, have become essential in determining the genetic causes of infertility. Moreover, the integration of genetics into reproductive medicine has expanded the scope of care to include not only affected individuals or couples but also their family members. Genetic consultations and counselling play a crucial role in identifying potentially affected relatives and offering tailored therapy and the possibility of fertility preservation. Despite the current limited therapeutic options, an increasing understanding of genotype-phenotype correlations in infertility genes holds promise for improved treatment outcomes. The availability of genetic diagnostic tools has reduced the number of idiopathic infertility cases by providing accurate aetiological diagnoses. The transition from research to clinical practice in reproductive genetics requires the establishment of genetic consultations and data warehousing systems to provide up-to-date information on gene-disease relationships. Overall, the integration of genetics into reproductive medicine has brought about a paradigm shift, emphasizing the familial dimension of infertility and offering new possibilities for personalized care and family planning.

Decoding the role of m6A Regulators in identifying and characterizing molecular subtypes of rosacea

Rosacea is a common skin disease that predominantly affects individuals aged between 30 and 50 years. While the exact cause of the disease remains unclear, various factors have been shown to trigger or exacerbate its symptoms. N6-methyladenosine (m6A) modification is one of the most abundant epigenetic methylation modification in messenger RNA (mRNA) and non-coding RNA (ncRNA), plays a crucial role in RNA splicing, export, stability, and translation. In this study, we aimed to characterize m6A genes in rosacea, identify molecular subtypes based on m6A gene expression, characterize the immune features among subtypes, explore key molecules based on co-expression analysis, and identify potential targets and drugs. To achieve our objectives, we first compared the expression pattern and immune regulation of m6A genes between healthy and diseased groups. Then, we performed clustering to stratify disease samples into different subtypes and analyzed immune regulation and functional enrichment among the subtypes. Then, we conducted differential analysis between subtypes and applied weighted gene co-expression network analysis (WGCNA) in three subtypes. We found hub differential expression analysis (DEG) genes and their potential drug based on the WGCNA results and the drug-gene interaction database (DGIdb). Finally, in vivo and in vitro studies showed significant differences in m6A methyltransferase METTL3 levels in rosacea mice and control mice, as well as in the skin of rosacea patients and healthy people, while reducing METTL3 significantly inhibited the inflammatory response of human fibroblasts (HDFs) stimulated by LL37, suggesting that METTL3 may be associated with changes in overall m6A levels in rosacea. Taken together, our findings provide valuable insights into therapeutic targets and drug predictions for rosacea.

Cutaneous Findings in Inborn Errors of Immunity: An Immunologist's Perspective

Cutaneous manifestations are common in patients with inborn errors of immunity (IEI)/primary immunodeficiency and could be due to infections, immune dysregulation, or lymphoproliferative/malign diseases. Immunologists accept some as warning signs for underlying IEI. Herein, we include noninfectious/infectious cutaneous manifestations that we come across in rare IEI cases in our clinic and provide a comprehensive literature review. For several skin diseases, the diagnosis is challenging and differential diagnosis is necessary. Detailed disease history and examination play a vital role in reaching a diagnosis, especially if there is a potential underlying IEI. A skin biopsy is sometimes necessary, especially if we need to rule out inflammatory, infectious, lymphoproliferative, and malignant conditions. Specific and immunohistochemical stainings are particularly important when diagnosing granuloma, amyloidosis, malignancies, and infections like human herpes virus-6, human herpes virus-8, human papillomavirus, and orf. Elucidation of mechanisms of IEIs has improved our understanding of their relation to cutaneous findings. In challenging cases, the immunological evaluation may lead the approach when there is a specific primary immunodeficiency diagnosis or at least help to reduce the number of differential diagnoses. Conversely, the response to therapy may provide conclusive evidence for some conditions. This review raises awareness of concomitant lesions and expands the scope of the differential diagnosis of IEI and the spectrum of skin disease therapy by highlighting frequent forms of IEI-associated cutaneous manifestations. The manifestations given here will guide clinicians to plan for alternative use of diverse therapeutics in a multidisciplinary way for skin diseases.

Inborn errors of immunity with loss- and gain-of-function germline mutations in STAT1

STAT1 dysfunction causes a wide range of immune dysregulation phenotypes, which have been classified into four disease types, namely, (i) autosomal recessive (AR) complete STAT1 deficiency, (ii) AR partial STAT1 deficiency, (iii) autosomal dominant (AD) STAT1 deficiency, and (iv) AD STAT1 gain of function (GOF), based on their mode of inheritance and function. Disease types (i, ii, and iii) are caused by STAT1 loss-of-function (LOF) mutations, whereas disease type (iv) is caused by STAT1 GOF mutations. Therefore, the functional analysis of mutations is necessary for the precise diagnosis.

Chronic Mucocutaneous Candidiasis: A Case Report

Chronic mucocutaneous candidiasis (CMC) is a rare infectious skin disease. This study reported a case of CMC in a child with clinical manifestations of oral mucosal leukoplakia and erythema and crust-like thick scabs on the skin of the face and upper limbs. Microscopic fungal examination revealed a large amount of pseudohyphae, and the fungal culture indicated Candida albicans. A drug sensitivity test indicated that it was sensitive to itraconazole and nystatin. Laboratory tests did not show significant immunodeficiency or endocrine abnormalities, and gene sequencing did not identify DNA gene mutations in the coiled-coil domain (CCD) or the DNA-binding domain (DBD) of signal transducer and activator of transcription 1 (STAT1). The skin lesions subsided after oral administration of itraconazole but relapsed 6 months later, and hypoparathyroidism occurred 1 year later. Patients with repeated superficial fungal infection should be alert to the possibility of CMC. CMC has numerous complications and a poor prognosis that requires the attention of clinicians. In this case, STAT1 mutation was not found, and parathyroid dysfunction was rare, providing reference for clinical diagnosis and treatment of CMC.

Dominant-negative signal transducer and activator of transcription (STAT)3 variants in adult patients: A single center experience

Background

Autosomal dominant hyper-IgE syndrome (AD-HIES) caused by dominant negative (DN) variants in the signal transducer and activator of transcription 3 gene (STAT3) is characterized by recurrent Staphylococcal abscesses, severe eczema, chronic mucocutaneous candidiasis (CMC), and non-immunological facial and skeletal features.

Objectives

To describe our experience with the diagnosis and treatment of adult patients with AD-HIES induced by DN-STAT3 variants.

Methods

The medical records of adult patients (>18 years) treated at the Allergy and Clinical Immunology Clinic of Hadassah Medical Center, Jerusalem, Israel, were retrospectively analyzed. Immune and genetic workups were used to confirm diagnosis.

Results

Three adult patients (2 males; age 29-41 years) were diagnosed with DN-STAT3 variants. All patients had non-immunological features, including coarse faces and osteopenia. Serious bacterial infections were noted in all patients, including recurrent abscesses, recurrent pneumonia, and bronchiectasis. CMC and diffuse dermatophytosis were noted in two patients. Two patients had severe atopic dermatitis refractory to topical steroids and phototherapy. Immune workup revealed elevated IgE in three patients and eosinophilia in two patients. Whole exome sequencing revealed DN-STAT3 variants (c.1166C>T; p.Thr389Ile in two patients and c.1268G>A; p. Arg423Gln in one patient). Variants were located in DNA-binding domain (DBD) and did not hamper STAT3 phosphorylation Treatment included antimicrobial prophylaxis with trimethoprim/sulfamethoxazole (n=2) and amoxycillin-clavulanic acid (n=1), and anti-fungal treatment with fluconazole (n=2) and voriconazole (n=1). Two patients who had severe atopic dermatitis, were treated with dupilumab with complete resolution of their rash. No adverse responses were noted in the dupilumab-treated patients.

Discussion

Dupilumab can be used safely as a biotherapy for atopic dermatitis in these patients as it can effectively alleviate eczema-related symptoms. Immunologists and dermatologists treating AD-HIES adult patients should be aware of demodicosis as a possible manifestation. DN-STAT3 variants in DBD do not hamper STAT3 phosphorylation.

Human follicular mites: Ectoparasites becoming symbionts

Most humans carry mites in the hair follicles of their skin for their entire lives. Follicular mites are the only metazoans tha continuously live on humans. We propose that Demodex folliculorum (Acari) represents a transitional stage from a host-injuring obligate parasite to an obligate symbiont. Here, we describe the profound impact of this transition on the genome and physiology of the mite. Genome sequencing revealed that the permanent host association of D. folliculorum led to an extensive genome reduction through relaxed selection and genetic drift, resulting in the smallest number of protein-coding genes yet identified among panarthropods. Confocal microscopy revealed that this gene loss coincided with an extreme reduction in the number of cells. Single uninucleate muscle cells are sufficient to operate each of the three segments that form each walking leg. While it has been assumed that the reduction of the cell number in parasites starts early in development, we identified a greater total number of cells in the last developmental stage (nymph) than in the terminal adult stage, suggesting that reduction starts at the adult or ultimate stage of development. This is the first evolutionary step in an arthropod species adopting a reductive, parasitic or endosymbiotic lifestyle. Somatic nuclei show underreplication at the diploid stage. Novel eye structures or photoreceptors as well as a unique human host melatonin-guided day/night rhythm are proposed for the first time. The loss of DNA repair genes coupled with extreme endogamy might have set this mite species on an evolutionary dead-end trajectory.