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Patients with chronic mucocutaneous candidiasis (CMC) have an unknown primary immune defect and are unable to clear infections with the yeast Candida. CMC includes patients with AIRE gene mutations who have autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), and patients without known mutations. CMC patients have dysregulated cytokine production, suggesting that defective expression of pattern recognition receptors (PRRs) may underlie disease pathogenesis. In 29 patients with CMC (13 with APECED) and controls, we assessed dendritic cell (DC) subsets and monocyte Toll-like receptor (TLR) expression in blood. We generated and stimulated monocyte-derived (mo)DCs with Candida albicans, TLR-2/6 ligand and lipopolysaccharide and assessed PRR mRNA expression by polymerase chain reaction [TLR-1–10, Dectin-1 and -2, spleen tyrosine kinase (Syk) and caspase recruitment domain (CARD) 9] in immature and mature moDCs. We demonstrate for the first time that CMC patients, with or without APECED, have normal blood levels of plasmocytoid and myeloid DCs and monocyte TLR-2/TLR-6 expression. We showed that in immature moDCs, expression levels of all PRRs involved in anti- Candida responses (TLR-1, -2, -4, -6, Dectin-1, Syk, CARD9) were comparable to controls, implying that defects in PRR expression are not responsible for the increased susceptibility to Candida infections seen in CMC patients. However, as opposed to healthy controls, both groups of CMC patients failed to down-regulate PRR mRNA expression in response to Candida, consistent with defective DC maturation, as we reported recently. Thus, impaired DC maturation and consequent altered regulation of PRR signalling pathways rather than defects in PRR expression may be responsible for inadequate Candida handling in CMC patients. [ABSTRACT FROM AUTHOR]

Patients with chronic mucocutaneous candidiasis (CMC) suffer persistent infections with the yeast Candida. CMC includes patients with autoimmune regulator (AIRE) gene mutations who have autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), and patients without known mutations. CMC patients have dysregulated cytokine production, and dendritic cells (DCs), as central orchestrators, may underlie pathogenic disease mechanisms. In 29 patients with CMC (13 with APECED) and controls, we generated monocyte-derived DCs, stimulated them with Candida albicans, Toll-like receptor-2/6 ligand and lipopolysaccharide to assess cytokine production [interleukin (IL)-12p70, IL-23, interferon (IFN)-γ, IL-2, tumour necrosis factor (TNF)-α, IL-6, transforming growth factor-β, IL-10, IL-5, IL-13] and cell-surface maturation marker expression (CD83, CD86, human leucocyte antigen D-related). In both APECED and non-APECED CMC patients, we demonstrate impairment of DC function as evidenced by altered cytokine expression profiles and DC maturation/activation: (1) both groups over-produce IL-2, IFN-γ, TNF-α and IL-13 and demonstrate impaired DC maturation. (2) Only non-APECED patients showed markedly decreased Candida-stimulated production of IL-23 and markedly increased production of IL-6, suggesting impairment of the IL-6/IL-23/T helper type 17 axis. (3) In contrast, only APECED patients showed DC hyperactivation, which may underlie altered T cell responsiveness, autoimmunity and impaired response to Candida. We demonstrate different pathogenic mechanisms on the same immune response pathway underlying increased susceptibility to Candida infection in these patients. [ABSTRACT FROM AUTHOR]

Patients with chronic mucocutaneous candidiasis (CMC) succumb to persistent infections with the opportunistic yeast Candida. Impaired cell-mediated responses to Candida have been repeatedly reported while antibody responses were mostly found to be normal. The underlying defect remains poorly understood. It has recently been shown that CMC patients are also susceptible to infections with encapsulated bacteria, and may have associated IgG2 and IgG4 deficiency. Our previous studies demonstrated altered cytokine production in CMC patients. As cytokines can influence production and isotype of specific antibody, in 10 patients with CMC we measured the levels and isotype distributions of serum antibodies to Candida antigens (CAg). pneumococcal polysaccharide (PPS) and tetanus toxoid (TT) antigens. Peripheral blood lymphocytes were also stimulated in culture and the antibodies made in vitro were measured. Our data demonstrated that in vivo, CMC patients had very high levels of IgG and IgA CAg-specific antibodies. CAg-specific and PPS specific IgG1 was markedly higher than in controls. Children but not adults with CMC had significantly lower levels of IgG2-specific antibody to CAg and PPS compared with age-matched controls. Patients had significantly higher levels of IgG3-specific antibody to all three antigens tested. These findings were in accordance with increased total IgG and IgG3 levels seen in CMC patients. In vitro, CMC patients, particularly children, did not respond as frequently to antigen stimulation as did their healthy controls. The level of specific antibody produced was also lower lo all antigens tested, as was the amount of total immunoglobulins following antigenic and particularly mitogenic stimulation. Addition of interferon-alpha (IFN-α) or IFN-β lo cultures had variable, sometimes marked, effects. Our results demonstrate that CMC patients manifest subtle alterations in specific antibody responses to CAg, PPS and TT, which are most pronounced in children. This may relate to altered cytokine production also seen in these patients. [ABSTRACT FROM AUTHOR]

Patients with chronic mucocutaneous candidiasis (CMC) present with persistent infections with the opportunistic yeast Candida. Impaired cell-mediated responses to Candida have been documented in CMC patients, but the defect remains poorly understood. The importance of Th1 cytokines in resistance and Th2 in susceptibility to Candida infections has recently been demonstrated in murine models. In our studies we evaluated production of IL-2 and IFN-γ (markers of Th1 type responses) as well as IL-4 and IL-6 (Th2 type markers) following stimulation with two kinds of Candida antigens (CAgs), polysaccharide antigens, tetanus toxoid and pokeweed mitogen. Our results demonstrate that CMC patients have impaired cytokine production upon in vitro stimulation with CAgs resulting in low or absent IL-2, increased IL-6 and either absent or increased IFN-γ production. Cytokine production following stimulation by other antigens was unaltered. The overall cytokine-producing capacity assessed through mitogen stimulation was also intact. Addition of IFN-α or IFN-γ to culture in an attempt to modify cytokine production did not have significant effects. Levels of soluble IL-6 receptors were not increased and could not account for increased IL-6 production. Our studies support the hypothesis that Candida antigens trigger a predominantly Th2 instead of a Th1 cytokine response in patients with CMC. [ABSTRACT FROM AUTHOR]