Primary immunodeficiency and chronic mucocutaneous candidiasis: pathophysiological, diagnostic, and therapeutic approaches.

Chronic mucocutaneous candidiasis (CMC) is characterized by a chronic or recurrent non-invasive infection, mainly due to Candida albicans, in skin, nails, and mucous membranes, associated in some cases with autoimmune manifestations. The key immune defect is a disruption of the action of cytokine IL-17, whose most common genetic etiology is STAT1 gene gain-of-function (GOF) mutations. The initial appropriate treatment for fungal infections is with azoles. However, the frequent occurrence of drug resistance is the main limitation. Therefore, identification of the underlying inborn error if immunity in CMC may allow to widen therapeutic options aimed at restoring immunological function. Type I and II Janus kinase-inhibitors have been shown to control CMC in cases associated with STAT1 GOF. In this review, we delve into the pathogenesis of CMC and the underlying immune mechanisms. We describe the reported genetic defects in which CMC is the main manifestation. Diagnostic and therapeutic approaches for these patients are also offered.

Chronic Candida infection, bronchiectasis, immunoglobulin abnormalities, and stunting: a case report of a natural mutation of STAT1 (c.986C>G) in an adolescent male.

BACKGROUND: Chronic mucocutaneous candidiasis (CMC) is the most common clinical symptom of singer transducer and signal transducer and activator of transcription 1 (STAT1) gain-of-function (GOF) mutations. Bronchiectasis is a chronic lung disease that is characterized by permanent bronchiectasis, causing cough, expectoration, and even haemoptysis. The underlying pathogeny is not yet clear. Immunoglobulin (Ig) A is derived from memory B cells and correlates with immune-related diseases. STAT1 is closely associated with signal transmission and immune regulation. CASE PRESENTATION: We report a 17-year-old male patient carrying a GOF mutation in STAT1. The variant led to CMC, bronchiectasis, and elevated serum IgA levels, as well as stunting. Whole-exome sequencing (WES) revealed a c.986C>G (p.P329R) heterozygous mutation in the STAT1 gene. CONCLUSION: Further Sanger sequencing analysis of STAT1 in the patient and his parents showed that the patient harboured a de novo mutation.

Aberrant type 1 immunity drives susceptibility to mucosal fungal infections.

Human monogenic disorders have revealed the critical contribution of type 17 responses in mucosal fungal surveillance. We unexpectedly found that in certain settings, enhanced type 1 immunity rather than defective type 17 responses can promote mucosal fungal infection susceptibility. Notably, in mice and humans with AIRE deficiency, an autoimmune disease characterized by selective susceptibility to mucosal but not systemic fungal infection, mucosal type 17 responses are intact while type 1 responses are exacerbated. These responses promote aberrant interferon-γ (IFN-γ)- and signal transducer and activator of transcription 1 (STAT1)-dependent epithelial barrier defects as well as mucosal fungal infection susceptibility. Concordantly, genetic and pharmacologic inhibition of IFN-γ or Janus kinase (JAK)-STAT signaling ameliorates mucosal fungal disease. Thus, we identify aberrant T cell-dependent, type 1 mucosal inflammation as a critical tissue-specific pathogenic mechanism that promotes mucosal fungal infection susceptibility in mice and humans.

Recurrent, Severe Aphthous Stomatitis and Mucosal Ulcers as Primary Manifestations of a Novel STAT1 Gain-of-Function Mutation.

Chronic mucocutaneous candidiasis (CMC) characterized by persistent and recurrent Candida infection of the skin, nails, and the mucosa membranes has been proposed as the major infectious phenotype in patients with gain-of-function mutation of signal transducer and activator of transcription 1 (STAT1) 1. However, viral infections caused mostly by herpesviruses, and a broad range of autoimmune disorders may also be part of the clinical phenotype. We report here on a 31 years old female patient suffering from severe mucosal aphthous mucositis and ulcers and recurrent herpes simplex for decades. We found a previously unknown heterozygous sequence variant in STAT1 (c.1219C>G; L407V) affecting the DNA-binding domain of the protein in the patient and her 4 years old daughter. We found this mutation gain-of-function (GOF) by using immunoblot and luciferase assays. We detected low proportion of IL-17A-producing CD4+ T cell lymphocytes by using intracellular staining and flow cytometry. Candida-induced secretion of IL-17A and IL-22 by mononuclear cells from the patient was markedly decreased compared to controls. These data suggest that the novel mutant allele may result in impaired differentiation of CD4+ T cells to CD4+/IL-17+ cells. The clinical phenotype of the disease in this patient was unique as it was dominated primarily by severe aphthous stomatitis and ulcerative esophagitis and only partly by typical CMC resulting in diagnostic delay. We suggest that patients with severe recurrent aphthous stomatitis and esophagitis should be evaluated for STAT1 GOF mutation. Based on the broad clinical spectrum of the disease, we also suggest that CMC and CMC disease may not be an appropriate term to define clinically STAT1 GOF mutation.

Ruxolitinib treatment of a patient with steroid-dependent severe autoimmunity due to STAT1 gain-of-function mutation.

Signal transducer and activator of transcription 1 gain-of-function (STAT1 GOF) mutations are the most common cause of chronic mucocutaneous candidiasis (CMC). We report the effect of oral ruxolitinib, an inhibitor of Janus kinase (JAK) family tyrosine kinases, on the clinical and immune status of a 3-year-old male with steroid-dependent severe autoimmunity due to a STAT1 GOF T385M mutation. The patient's susceptibility to infection improved with antimicrobial prophylaxis and immunoglobulin replacement therapy, but he continued to exhibit severely disabling symptoms of autoimmunity. More than one-third of patients with STAT1 GOF mutations present with autoimmune manifestations, and this patient's mutation was reported to cause CMC with autoimmunity. We analyzed the interleukin (IL)-17A and IFN-γ levels and immunophenotype by flow cytometry before and during treatment with ruxolitinib. The peripheral IL-17A level did not increase, but the IFN-γ level decreased after 4 months of therapy. The STAT1 phosphorylation level decreased significantly upon stimulation of patient cells with IFN-γ. Clinically, cytomegalovirus reactivation occurred, but was controlled. No other adverse effect was noted. We report the potential of JAK1/2 inhibition with ruxolitinib for both CMC and steroid-dependent autoimmunity. However, long-term administration is necessary, as the effect is not sustained after treatment is discontinued.

Chronic mucocutaneous candidiasis and connective tissue disorder in humans with impaired JNK1-dependent responses to IL-17A/F and TGF-ß.

Genetic etiologies of chronic mucocutaneous candidiasis (CMC) disrupt human IL-17A/F-dependent immunity at mucosal surfaces, whereas those of connective tissue disorders (CTDs) often impair the TGF-ß-dependent homeostasis of connective tissues. The signaling pathways involved are incompletely understood. We report a three-generation family with an autosomal dominant (AD) combination of CMC and a previously undescribed form of CTD that clinically overlaps with Ehlers-Danlos syndrome (EDS). The patients are heterozygous for a private splice-site variant of MAPK8, the gene encoding c-Jun N-terminal kinase 1 (JNK1), a component of the MAPK signaling pathway. This variant is loss-of-expression and loss-of-function in the patients' fibroblasts, which display AD JNK1 deficiency by haploinsufficiency. These cells have impaired, but not abolished, responses to IL-17A and IL-17F. Moreover, the development of the patients' TH17 cells was impaired ex vivo and in vitro, probably due to the involvement of JNK1 in the TGF-ß-responsive pathway and further accounting for the patients' CMC. Consistently, the patients' fibroblasts displayed impaired JNK1- and c-Jun/ATF-2-dependent induction of key extracellular matrix (ECM) components and regulators, but not of EDS-causing gene products, in response to TGF-ß. Furthermore, they displayed a transcriptional pattern in response to TGF-ß different from that of fibroblasts from patients with Loeys-Dietz syndrome caused by mutations of TGFBR2 or SMAD3, further accounting for the patients' complex and unusual CTD phenotype. This experiment of nature indicates that the integrity of the human JNK1-dependent MAPK signaling pathway is essential for IL-17A- and IL-17F-dependent mucocutaneous immunity to Candida and for the TGF-ß-dependent homeostasis of connective tissues.

Successful Allogenic Stem Cell Transplantation in Patients with Inherited CARD9 Deficiency.

Autosomal recessive (AR) CARD9 (caspase recruitment domain-containing protein 9) deficiency underlies invasive infections by fungi of the ascomycete phylum in previously healthy individuals at almost any age. Although CARD9 is expressed mostly by myeloid cells, the cellular basis of fungal infections in patients with inherited CARD9 deficiency is unclear. Therapy for fungal infections is challenging, with at least 20% premature mortality. We report two unrelated patients from Brazil and Morocco with AR CARD9 deficiency, both successfully treated with hematopoietic stem cell transplantation (HSCT). From childhood onward, the patients had invasive dermatophytic disease, which persisted or recurred despite multiple courses of antifungal treatment. Sanger sequencing identified homozygous missense CARD9 variants at the same residue, c.302G>T (p.R101L) in the Brazilian patient and c.301C>T (p.R101C) in the Moroccan patient. At the ages of 25 and 44 years, respectively, they received a HSCT. The first patient received a HLA-matched HSCT from his CARD9-mutated heterozygous sister. There was 100% donor chimerism at D + 100. The other patient received a T cell-depleted haploidentical HSCT from his CARD9-mutated heterozygous brother. A second HSCT from the same donor was performed due to severe amegakaryocytic thrombocytopenia despite achieving full donor chimerism (100%). At last follow-up, more than 3 years after HSCT, both patients have achieved complete clinical remission and stopped antifungal therapy. HSCT might be a life-saving therapeutic option in patients with AR CARD9 deficiency. This observation strongly suggests that the pathogenesis of fungal infections in these patients is largely due to the disruption of leukocyte-mediated CARD9 immunity.

Recurrent fungal infections in a Chinese patient with CARD9 deficiency and a review of 48 cases.

Deficiency of CARD9 (caspase recruitment domain-containing protein 9) has been reported in individuals with recurrent and invasive fungal infections. We report on a patient who first had Trichosporon asahii affecting the skin then Candida albicans infections involving the digestive tract and knee joint, along with elevated serum IgE. After stimulation with C. albicans, peripheral blood mononuclear cells of this patient produced less tumour necrosis factor-α, interferon-γ and interleukin-17 than those of healthy controls. Furthermore, the serum IgE levels of this patient were positively correlated with the severity of fungal infection during the course of treatment. Sanger sequencing identified one homozygous frameshift mutation (p.D274fsX60) in CARD9. We further performed a review including 48 cases with CARD9 deficiency. According to the data published previously, CARD9-deficient patients demonstrated obviously elevated IgE in serum (median 1300 IU mL-1 ), which could distinguish them from otherwise healthy people with fungal infections (area under the curve 0·94, P < 0·001). Patients carrying the mutations Q289X and Q295X had a higher mortality rate (24% vs. 0%, P < 0·05). Patients with the mutations R18W, R35Q, R70W, G72S or Y91H in the CARD domain, and the nonsense mutation Q295X in the coiled-coil domain, seemed to be more prone to Candida infections (90% vs. 20%, P < 0·005) and central nervous system infections (60% vs. 12%, P < 0·005).

Chronic Mucocutaneous Candidiasis in Autoimmune Polyendocrine Syndrome Type 1.

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is an autosomal recessive disease caused by mutations in the autoimmune regulator (AIRE) gene, characterized by the clinical triad of chronic mucocutaneous candidiasis (CMC), hypoparathyroidism, and adrenal insufficiency. CMC can be complicated by systemic candidiasis or oral squamous cell carcinoma (SCC), and may lead to death. The role of chronic Candida infection in the etiopathogenesis of oral SCC is unclear. Long-term use of fluconazole has led to the emergence of Candida albicans strains with decreased susceptibility to azoles. CMC is associated with an impaired Th17 cell response; however, it remains unclear whether decreased serum IL-17 and IL-22 levels are related to a defect in cytokine production or to neutralizing autoantibodies resulting from mutations in the AIRE gene.

Bronchiectasis and Recurrent Respiratory Infections with a De Novo STAT1 Gain-of-Function Variant: First Case in Korea.

Bronchiectasis is a chronic disease characterized by airway infection and inflammation, leading to permanent dilation of the bronchi. Evaluation of underlying etiology is important in managing young bronchiectasis patients with recurrent infections caused by unusual pathogens. The signal transducer and activator of transcription 1 (STAT1) protein plays a key role in STAT signaling and immune system regulation. Heterozygotes for gain-of-function (GOF) alleles of the STAT1 gene usually display autosomal dominant chronic mucocutaneous candidiasis (CMC) and a wide range of clinical features, such as bronchiectasis. Here, we report on a patient with CMC and bronchiectasis with various types of infections who carried a pathogenic variant of the STAT1 gene. The 24-year-old female presented with recurrent respiratory bacterial and nontuberculous mycobacterial infections complicated by severe bronchiectasis and CMC. Whole-exome sequencing revealed a c.800C>T (p.Ala267Val) heterozygous mutation in the STAT1 gene. Further analysis by Sanger sequencing of STAT1 from the patient and her parents revealed the patient had a de novo occurrence of the variant. This is the first report of a Korean patient with a GOF pathogenic variant in STAT1. Physicians should be aware of the existence of this variant as a genetic factor associated with CMC and bronchiectasis complicated by recurrent infection.

HDAC inhibitors modulate innate immune responses to micro-organisms relevant to chronic mucocutaneous candidiasis.

Signal transducer and activator of transcription 1 (STAT-1) gain-of-function (GOF) mutations cause chronic mucocutaneous candidiasis (CMC), a disease associated with Candida albicans and Staphylococcus aureus infection. Patients suffer from dysegulated immune responses due to aberrant cell programming and function. We investigated the effect of inhibitory molecules targeting histone deacetylases (HDACi) on the immune responses of peripheral blood mononuclear cells (PBMCs) of healthy controls and patients with CMC towards microbes relevant for CMC. PBMCs cells were pretreated with HDACi and challenged with C. albicans or S. aureus. Innate and adaptive cytokines were measured in cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). We assessed the effect of HDAC inhibitors on T helper type 1 (Th1) and Th17 cells and measured STAT-1 and STAT-3 phosphorylation using flow cytometry. Panobinostat, a pan-HDAC inhibitor, strongly inhibits innate and adaptive cytokines upon challenge with C. albicans or S. aureus. Specific inhibitors (entinostat or RGFP966) also had a tendency to lower production of most innate cytokines in CMC patient cells. Entinostat and RGFP966 increased the production of interleukin (IL)-22 specifically after S. aureus challenge in patient cells. In healthy and control cells, entinostat and RGFP966 treatment down-regulated STAT-1 phosphorylation while pSTAT-3 levels remained stable. HDACi modulate cytokine production in response to C. albicans and S. aureus. Pan-inhibitors lower overall cytokine production, whereas specific inhibitors confer a selective effect. Entinostat and RGFP966 are promising therapeutic candidates to treat STAT-1 GOF due to their capacity to restore IL-22 production and decrease STAT-1 phosphorylation; however, their inhibition of innate cytokines poses a possible risk to secondary infections.

Verrucous Plaque With Unusually Large Candida Blastoconidia: A Unique Clinicopathological Presentation of Systemic Mucocutaneous Candidiasis.

Mucocutaneous candidiasis is a common infection affecting both immunocompetent and immunosuppressed individuals. Diversity in the clinical and histopathological presentation of mucocutaneous candidiasis is well known. However, the occurrence of cutaneous verrucous lesions and giant yeast-like structures has been rarely reported. In this article, we describe a case of disseminated mucocutaneous candidiasis in an immunosuppressed patient who presented as a verrucous plaque on the scrotum with giant Candida blastoconidia. This peculiar presentation expands the clinicopathological spectrum of mucocutaneous candidiasis and highlights the wide range of clinical manifestations and great morphologic variability of this common fungal infection.

Chronic mucocutaneous candidiasis, a case study and literature review.

Chronic mucocutaneous candidiasis (CMC) is a clinically heterogeneous disease. Some immunologic and hormonal abnormalities have been associated with CMC. The factors that predispose host to CMC infection could be autosomal or acquisitive. The disease usually occurs in childhood. Here, we reviewed the published literature on chronic mucocutaneous candidiasis and a four years old girl is presented with CMC. She had a history of recurrent thrush and otomycosis since the age of one. Candida albicans was detected in skin scraping and biopsy samples. Serum iron was low. TSH hormone level was high and T4 level was low. Giardia cysts were found in stool sample. Mucocutaneous and nail manifestations of the disease were disappeared after a period of Itraconazole therapy.

Impaired Specific Antifungal Immunity in CARD9-Deficient Patients with Phaeohyphomycosis.

Phaeohyphomycosis is a group of severe infections caused by dematiaceous fungi. We previously identified CARD9 deficiencies in four Chinese patients with phaeohyphomycosis caused by Phialophora verrucosa. In this study, we sought to identify the genetic and immunological mechanisms underlying rare dematiaceous fungal infections in three otherwise healthy patients with phaeohyphomycosis caused by Exophiala spinifera, Ochroconis musae, and Corynespora cassiicola. CARD9 sequencing in these patients showed one mutation (p.S23X) that, to our knowledge, has not been characterized and two previously characterized mutations (p.D274fsX60 and p.L64fsX59) that led to lack of CARD9 protein expression. Patient-derived CARD9-deficient cells showed a selective impairment of proinflammatory cytokine and chemokine production, NF-κB activation, and T helper type 22- and T helper type 17-associated responses upon fungus-specific stimulation, whereas phagocytosis and reactive oxygen species production were intact. Consistently, Card9-knockout mice were highly susceptible to phaeohyphomycosis and exhibited immune deficiencies similar to those of patients, including diminished NF-κB and p38 MAPK activation in local and in vitro functional studies. This work clarifies the association between inherited CARD9 deficiencies and phaeohyphomycosis, and furthers current knowledge on the spectrum and pathophysiology of diseases resulting from CARD9 deficiencies.

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.