A non-classical presentation of APECED in a family with heterozygous R203X AIRE gene mutation.

PURPOSE: Biallelic loss-of-function mutations of AIRE cause the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome. However, single nucleotide mutations may cause a milder phenotype. In this paper, we describe an unusual and mild phenotype in a mother and her two children (son and daughter) who carry a rare heterozygous mutation of AIRE. METHODS AND RESULTS: The son presented with alopecia and subclinical hypothyroidism due to Hashimoto's Thyroiditis (HT); the daughter had alopecia, vaginal mycosis, stomach pains and subclinical hypothyroidism due to HT; and the mother had alopecia, vaginal mycosis and stomach pains. Organ- and non-organ-specific autoantibodies were evaluated as well as antibodies against interleukin-17A, -17F, -22 (IL-Abs) and interferon -α and -ω (IFN-Abs). The organ- and non-organ-specific autoantibodies screening was negative in the son, while the daughter was positive for liver-kidney microsomal antibodies (LKMAbs) and the mother was positive for glutamic acid decarboxylase antibodies (GADAbs). Daughter and mother were also positive for IFN-Abs. Analysis of the AIRE gene identified a rare heterozygous R203X mutation in all three family members. CONCLUSIONS: We describe for a first time a family with heterozygous R203X AIRE mutation causing an APECED-like condition, as confirmed by presence of IFN-Abs. The unusual mild phenotype should be reassuring for the patients and assist in their clinical management.

Autoimmune polyendocrine syndrome type 1 (APECED) in the Indian population: case report and review of a series of 45 patients.

BACKGROUND: Autoimmune polyendocrinopathy-candidiasis-ectodermal-dystrophy (APECED) or autoimmune polyglandular syndrome type 1 (APS-1) is a rare autosomal recessive genetic disease due to mutations in the AIRE (AutoImmune REgulator) gene. The clinical diagnosis is classically based on the presence of at least two of the three main components: chronic mucocutaneous candidiasis, hypoparathyroidism and primary adrenal insufficiency. Patients often suffer from other endocrine or non-endocrine autoimmune conditions throughout life. APECED etiopathogenesis is mediated by T lymphocytes. Autoantibodies against proteins of the affected organs are found in the serum of APECED patients as well as neutralizing antibodies against cytokines. We report here the clinical and genetic characteristics of 45 Indian APECED patients in comparison to Finnish, Sardinian, Turkish and North/South American cohorts from their published results. We also report a new case of APECED of Indian origin, a 2-year old child suffering from chronic mucocutaneous candidiasis since the age of 8 months, with confirmatory AIRE homozygous mutation c.274C > T (p.R92W). CONCLUSION: With the inherent limitations of a retrospective study, analysis of Indian APECED patients suggested that compared to classic criteria, application of Ferre/Lionakis criteria validated in North/South American patients could help in earlier diagnosis in 3 of 8 (37.5%) patients for whom adequate information for evaluation was available.

[Chronic mucocutaneous candidiasis with STAT1 gain-of-function mutation associated with herpes virus and mycobacterial infections]. / Candidose cutanéo-muqueuse chronique avec mutation gain-de-fonction du gène STAT1 associée à des infections herpétiques et à mycobactérie.

INTRODUCTION: Chronic mucocutaneous candidiasis (CMC) is characterized by susceptibility to chronic or recurrent infections with yeasts of the genus Candida affecting the skin, nails and mucous membranes. We describe a Moroccan patient presenting CMC with heterozygous STAT1 gain-of-function (GOF) mutation. PATIENTS AND METHODS: A 5-year-old boy with no consanguinity presented recurrent episodes of oral thrush, chronic nail candidiasis and herpetic gingivostomatitis from the age of 8 months. He also had mycobacterial adenitis secondary to BCG vaccination and atypical rosacea. Genetic analysis revealed GOF mutation of the STAT1 gene. DISCUSSION: CMC was diagnosed in our patient despite poor clinical features. Sequencing of the genome revealed STAT1GOF mutation. This mutation affects production of IL-17, an important cytokine in mucocutaneous defense against Candida. The association with mycobacterial adenitis is rare and continues to be poorly understood. The presence of atypical rosacea in this setting is suggestive of this entity. Antifungal therapy and prevention of complications are necessary to reduce the morbidity and mortality associated with this condition. CONCLUSION: CMC due to STAT1GOF mutation is characterized by a broad clinical spectrum and should be considered in all cases of chronic or recurrent fungal infection, whether or not associated with other infections.

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.

IL-17 and infections.

IL-17 immunity has been shown to be essential for mucocutaneous protection against Candida albicans in mice and humans. However, mice with defective IL-17 immunity display broader susceptibility, as they are also prone to infections with diverse infectious agents at various sites. Humans with genetic defects affecting their IL-17 immunity usually suffer from chronic mucocutaneous candidiasis (CMC): recurrent or persistent infections of the skin, nails, and mucosae with C. albicans, with or without other clinical signs. Most patients with autosomal dominant (AD) hyper-IgE syndrome (HIES) due to STAT3 deficiency or AD STAT1 gain-of-function display impaired IL-17-producing T-cell development, and CMC is one of their principal clinical manifestations. Similarly, patients with autosomal recessive (AR) autoimmune polyendocrine syndrome type 1 (APS-1) caused by AIRE deficiency have high levels of neutralizing autoantibodies against IL-17A, IL-17F and/or IL-22 and present CMC as their only infectious disease. Finally, CMC is the main clinical phenotype observed in patients with inborn errors specifically affecting IL-17 immunity. Indeed, patients with AD IL-17F deficiency or AR IL-17RA or ACT1 deficiency display CMC and, to a lesser extent, superficial staphylococcal diseases. Candida infection was recently reported in psoriasis patients treated with anti-IL-17A antibodies. Careful monitoring for CMC is thus important during anti-IL-17 treatment.

Defective IL7R expression in T(-)B(+)NK(+) severe combined immunodeficiency.

Severe combined immunodeficiency (SCID) is caused by multiple genetic defects. The most common form of SCID, X-linked SCID (XSCID), results from mutations in IL2RG (ref. 4), which encodes the common cytokine receptor gamma chain (gamma(c)) that is shared by the IL-2, IL-4, IL-7, IL-9 and IL-15 receptors. In XSCID and SCID resulting from mutations in JAK3, which encodes a Janus family tyrosine kinase that couples to gamma(c) and is required for gamma(c)-dependent signalling, T- and natural killer (NK)-cells are decreased but B-cell numbers are normal (T(-)B(+)NK(-)SCID). Some SCID patients lack T cells but retain NK cells. Given diminished T-cell development in Il7- or Il7r-deficient mice and that Il/7r-deficient mice have NK cells, we hypothesized that T(-)B(+)NK(+) SCID might result from defective IL-7 signalling, although apparent differences in the role of the IL-7/IL-7R pathway in humans and mice in T-cell and B-cell development have been suggested. We now demonstrate that defective IL7R expression causes T(-)B(+)NK(+) SCID, indicating that the T-cell, but not the NK-cell, defect in XSCID results from inactivation of IL-7Ralpha signalling.

Mucocutaneous IL-17 immunity in mice and humans: host defense vs. excessive inflammation.

Interleukin (IL)-17A is a pro-inflammatory cytokine in mice and humans. It is recognized as a key factor for the protection of mice against various pathogens, but it also underlies pathogenic inflammatory responses in numerous mouse models. The inborn errors of IL-17A- and IL-17F-mediated immunity identified in humans in the last decade have revealed that IL-17A and IL-17F are key players in mucocutaneous immunity to Candida albicans, and, to a lesser extent, Staphylococcus aureus. By contrast, there is currently no genetic evidence for a causal link between excess of IL-17 and autoimmunity, autoinflammation, or allergy in humans. We discuss here the physiological and pathological roles of mouse and human IL-17A and IL-17F in host defense and excessive inflammation. We highlight recent advances in our understanding of the consequences of deficient or excessive IL-17 immunity at various mucocutaneous sites, including the oral cavity, skin, intestine, lungs, and vagina.

Mutations in the gene for the IL-7 receptor result in T(-)B(+)NK(+) severe combined immunodeficiency disease.

Recently, two SCID (severe combined immunodeficiency disease) patients with greatly diminished T cells but normal or increased numbers of B and NK cells (T(-)B(+)NK(+) SCID) were found to have mutations in the gene for the IL-7 receptor. This has established a major role for IL-7-receptor-dependent signaling in T cell development in humans and probably explains the diminished T cell numbers seen in patients with X-linked SCID or SCID that results from Jak3-deficiency.

New clinical phenotypes of fungal infections in special hosts.

Incidence of invasive fungal infections increases over time with the rise in at-risk populations; in particular, patients with acquired immunodeficiencies due to immunosuppressive therapies such as anti-tumour necrosis factor-α (TNF-α) treatment, cirrhosis or burns. Some primary immunodeficiencies (PID) can also predispose selectively to invasive fungal diseases. Conversely, some atypical fungal diseases can reveal new PID. Deep dermatophytosis, Candida central nervous system infections or gastrointestinal disease, or disseminated phaeohyphomycosis-revealed CARD9 deficiency. Most patients with inherited chronic mucocutaneous candidiasis were found to carry STAT1 gain-of-function mutations. The spectrum of fungal susceptibility and clinical presentation varies according to the PID. Among acquired immunodeficiencies, immunosuppressive treatments such as TNF-α blocker therapy, which has revolutionized autoimmune disorder treatment, may be complicated by endemic mycosis, aspergillosis, pneumocystosis or cryptococcosis. Burn patients with damaged skin barrier protection are susceptible to severe Candida infections and filamentous fungal infections (such as Aspergillus spp., Mucorales). Moreover, patients with cirrhosis are at increased risk of fungal infections. Therefore, physicians should think of any potential underlying acquired or inherited immunodeficiency in a patient developing an atypical fungal infection, or of a potential fungal disease in the context of an atypical presentation in specific hosts.

Genes responsible for quantitative regulation of antibody production.

Evidence is first presented demonstrating that the individual capacity for antibody responsiveness has an inheritable component. The main evidence consists of spontaneous mutations causing either immunodeficiency or predisposition to autoimmunity in human and animals, and the involvement of some obvious candidate genes (in particular those belonging to the highly polymorphic histocompatibility and Igh loci), extensively analyzed in many mouse strain combinations. One finding constantly emerging from these studies is that single gene expression depends on environmental effects, lowering the genotype/phenotype correlation, but also on multigenic interactions appearing as background effects. The models available for the analysis of this multigenic regulation are discussed with special emphasis on the high and low antibody responder mice produced for this purpose by bidirectional selective breeding. The major advantage of this model is that the interline difference is huge and multispecifically expressed. The second part of the review presents the recent results on positional mapping of genes with immunomodulatory effects in this model and in one appropriate recombinant congenic strain series. This in vivo genetic dissection of antibody responsiveness discriminated the involvement of candidate genes and suggested that unsuspected genes might be identified by means of this wide open search.

IL-17 and infections

IL-17 immunity has been shown to be essential for mucocutaneous protection against Candida albicans in mice and humans. However, mice with defective IL-17 immunity display broader susceptibility, as they are also prone to infections with diverse infectious agents at various sites. Humans with genetic defects affecting their IL-17 immunity usually suffer from chronic mucocutaneous candidiasis (CMC): recurrent or persistent infections of the skin, nails, and mucosae with C. albicans, with or without other clinical signs. Most patients with autosomal dominant (AD) hyper-IgE syndrome (HIES) due to STAT3 deficiency or AD STAT1 gain-of-function display impaired IL-17-producing T-cell development, and CMC is one of their principal clinical manifestations. Similarly, patients with autosomal recessive (AR) autoimmune polyendocrine syndrome type 1 (APS-1) caused by AIRE deficiency have high levels of neutralizing autoantibodies against IL-17A, IL-17F and/or IL-22 and present CMC as their only infectious disease. Finally, CMC is the main clinical phenotype observed in patients with inborn errors specifically affecting IL-17 immunity. Indeed, patients with AD IL-17F deficiency or AR IL-17RA or ACT1 deficiency display CMC and, to a lesser extent, superficial staphylococcal diseases. Candida infection was recently reported in psoriasis patients treated with anti-IL-17A antibodies. Careful monitoring for CMC is thus important during anti-IL-17 treatment

Se ha demostrado que la inmunidad IL-17 es esencial para la protección mucocutánea contra la Candida albicans en ratones y humanos. Independientemente, los ratones con inmunidad IL-17 defectuosa muestran una susceptibilidad más amplia, de modo que también son propensos a infecciones por diversos agentes infecciosos en varios lugares. Los humanos con defectos genéticos que afectan su inmunidad IL-17 habitualmente padecen candidiasis mucocutánea crónica (CMC): infecciones cutáneas recurrentes o persistentes de uñas y mucosas por C. albicans, con o sin otros signos clínicos. Muchos pacientes con síndrome de hiper IgE autosómico dominante (AD-HIES) debido a deficiencia STAT3 o a aumento de función AD STAT1 muestran un desarrollo dañado de células T productoras de IL-17 y la CMC es una de sus principales manifestaciones. De igual manera, los pacientes con síndrome poliendocrino autoinmune tipo 1 recesivo autosómico (AR-APS-1) causado por deficiencia de AIRE (regulador autoinmune) presentan altos niveles de anticuerpos neutralizantes contra IL-17A, IL-17F y/o IL-22 y padecen CMC como su única enfermedad infecciosa. Finalmente, la CMC es el principal fenotipo clínico observado en pacientes con errores innatos, específicamente aquellos que afectan la inmunidad IL-17. De hecho, los pacientes con deficiencia AD IL-17F o deficiencia IL-17RA o ACT1 presentan CMC y, en menor medida, enfermedades estafilocócicas superficiales. Se ha informado recientemente CMC en pacientes tratados con anticuerpos anti-IL-17A. Es importante el control cuidadoso de la CMC en estos pacientes durante el tratamiento con anti-IL-17ª

Toward genetic dissection of high and low antibody responsiveness in Biozzi mice.

Several distinct chromosomal segments were recently identified by cosegregation analysis of polymorphic markers with antibody responsiveness in an F2 cross between high (H) and low (L) antibody responder lines of Biozzi mice. The effect associated with the relevant markers has now been investigated in backcross populations (toward the L line) bred from H and L mice made coisogenic at the H-2 locus. The antibody titers, measured on days 5 and 14 of the primary response to sheep red blood cells, were considered to be two distinct quantitative phenotypes. The results of single or multilocus analyses demonstrated the significant involvement, at one or the two titration times, of Im gene(s) on four distinct chromosomes: 4, 8, 12, and 18. The regions on chromosomes 6 and 10 have a lesser but still suggestive effect. The contribution of each locus ranged from 3% to 13%, and together these loci accounted for about 40% of the phenotypic variance at each titration time. The data are compatible with an additive effect of the relevant loci and suggestive of some interaction effects. In a second backcross toward L line, the H line alleles of the putative Im genes on chromosomes 6, 8, and 12 were isolated from each other and their effects were still detected.

Mapping of genes controlling quantitative antibody production in Biozzi mice.

An extensive search for in vivo immunomodulatory genes (Im genes) was made, using highly polymorphic DNA markers (microsatellites), in F2 hybrids between the two lines of mice selected for high (H) or low (L) Ab production (Biozzi mice). H and L mice have extreme phenotypes resulting from the accumulation, during selective breeding, of genes endowed with, respectively, upward or downward additive effects on Ab production. A total genome screening with 90 microsatellite markers (polymorphic between H and L mice) was conducted in 60 F2 hybrids sorted out for their extreme phenotypes from an immunized population of 240 individuals. A difference in parental marker frequency between these two groups (measured by a chi2 test) reveals the presence of an Im gene close to the marker. Significant chi2 scores were indeed found in two regions corresponding to the MHC and Igh loci, already identified as partly contributing to the H/L phenotypic difference. A notable finding was the demonstration that a gene(s), located on the proximal part of chromosome 6, was linked with Ab responsiveness. Other markers at distinct chromosomal regions also give increased chi2 scores, the two regions most clearly pointed out being on chromosomes 4 and 8.

Susceptibility and resistance to Leishmania amazonensis in H-2q syngeneic high and low antibody responder mice (Biozzi mice).

H-2 syngeneic H and L (Biozzi) mice provide a model to study Leishmania infections in which polar resistant and susceptible phenotypes are independent from H-2 differences. High-Ab-responder (H) and low-Ab-responder (L) mice syngeneic at the H-2 locus (H-2q) were, respectively, susceptible and highly resistant to Leishmania amazonensis infection. L-mice resistance was associated with high IFN-gamma and transient IL-4 production by lymph node (LN) cells, in contrast with sustained IL-4 and decreasing IFN-gamma production by susceptible H mice. IL-12 production could be detected only in LN from resistant mice. The cytokine production pattern was consistent with preferential progression to a Th1-type response in resistant L-mice, and to a Th2-type response in susceptible H-mice. We also investigated whether this shift towards Th1- or Th2-type cytokine responses was dependent upon H or L antigen presenting cells' (APC) intrinsic ability to preferentially stimulate either T-cell subset. To this end, LN-derived T-cell lines were grown from 12-day infected mice, when both strains produced IFN-gamma and IL-4. L-derived T-cell lines developed a Th2 cytokine pattern whereas H-derived T-cell lines produced IFN-gamma, IL-4 and IL-10 whatever the APC origin (H or L) used for their derivation. This work constitutes the first characterization of cellular immune responses to the intracellular parasite, L. amazonensis in H-2 syngeneic mice, an infection model in which polar resistant and susceptible phenotypes are determined by non-MHC genes.

Identification of two quantitative trait loci involved in antibody production on mouse chromosome 8.

Several quantitative trait loci (QTLs) contributing to the extreme phenotypes of the selected high (H) and low (L) antibody-responder lines of mice were mapped on distinct chromosomes. Successive backcrosses were bred to reduce the length of the QTL-bearing segment detected on chromosome 8 and to produce congenic lines to test gene effect independently of the other QTLs. An increase in antibody responses was repeatedly found to be associated with inheritance of the H-line allele at two markers separated by 30 cM on that chromosome. In the successive backcrosses, background and unlinked involved genes of H-line origin were progressively eliminated; however, unexpected within-progeny variations persisted in the third and even fourth backcross. Nevertheless, the presence of two QTLs within the considered interval was definitely demonstrated in distinct progenies of the fourth backcross which separately inherited one of the two gene-marker H-line alleles. The previously identified chromosome 8 segment therefore contains at least two QTLs involved in antibody responsiveness.

NKT lymphocyte ontogeny and function are impaired in low antibody-producer Biozzi mice: gene mapping in the interval-specific congenic strains raised for immunomodulatory genes.

NKT cells are CD4(+) or CD4(-)CD8(-) CD1d-restricted lymphocytes, characterized by the property to rapidly produce IL-4 and IFN-gamma in response to TCR ligation. This IL-4 burst is lacking in autoimmunity-prone SJL and NOD strains of mice, which suggests an immunoregulatory role for NKT cells. The NKT cell status was thus investigated in the genetically selected high (H) and low (L) antibody-producer mice. The results show that (i) the frequency of cells expressing the NKT cell markers is 3- to 4-fold lower in thymus and spleen from L than H mice, (ii) L mice spleen cells did not produce IL-4 following injection of anti-TCR alpha beta antibody, and (iii) L mice thymus and spleen cells failed to produce IL-4 after in vitro stimulation by anti-TCR alpha beta antibody or alpha-galactosylceramide, a newly described NKT cell ligand. These parameters were investigated in six interval-specific congenic strains raised for the quantitative trait loci which contain the immunomodulatory genes responsible for the high/low antibody production phenotypes. IL-4 production recovery occurred only in the congenic strain in which the H origin chromosome 4 segment was introgressed on the L background. This finding was not due to increased NKT cell frequency but appeared dependent of antigen-presenting cells in co-culture experiments. This result strongly suggests the presence of gene(s) modulating NKT function on chromosome 4, close to several genes predisposing to autoimmunity.