Human MD2 deficiency-an inborn error of immunity with pleiotropic features.

BACKGROUND: Toll-like receptors (TLRs) are important pattern recognition receptors that sense microbes and control host defense. Myeloid differentiation protein 2 (MD2) is the indispensable coreceptor for TLR4, facilitating the binding to the gram-negative bacterial cell wall component LPS and activation of downstream signaling. OBJECTIVE: We sought to provide phenotypic and mechanistic insights into human MD2 deficiency. METHODS: To elucidate the genetic cause in a patient with very early onset inflammatory bowel disease, we performed whole-exome sequencing and studied the functional consequences of the identified mutation in LY96 (encoding for MD2) in genetically engineered induced pluripotent stem cell-derived macrophages with knockout of MD2 or knockin of the patient-specific mutation, including TLR4-mediated signaling, cytokine production, and bacterial handling. RESULTS: Whole-exome sequencing identified a homozygous in-frame deletion in the LY96 gene (c.347_349delCAA; p.Thr116del) in a patient with very early onset inflammatory bowel disease and a sibling presenting with pneumonia and otitis media. Induced pluripotent stem cell-derived macrophages with knockout of MD2 or expression of the Thr116del mutation showed impaired activation of nuclear factor kappa B and mitogen-activated protein kinase signaling as well as TLR4 endocytosis on challenge with LPS or bacteria. In addition, MD2-deficient macrophages showed decreased cytokine expression (eg, IL-6, TNF, and IL-10) in response to LPS or gram-negative but not gram-positive bacteria. CONCLUSIONS: Human MD2 deficiency causes defective TLR4 signaling in response to LPS or gram-negative bacteria. The clinical manifestations and expressivity might be variable due to unknown secondary risk factors. Because TLR4 represents a therapeutic target for multiple inflammatory conditions, our study may provide insights into potential side effects of pharmacological TLR4 targeting.

Molecular epidemiology of non-syndromic autosomal recessive congenital ichthyosis in a Middle-Eastern population.

Autosomal recessive congenital ichthyosis (ARCI) is a rare and heterogeneous skin cornification disorder presenting with generalized scaling and varying degrees of erythema. Clinical manifestations range from lamellar ichthyosis (LI), congenital ichthyosiform erythroderma (CIE) through the most severe form of ARCI, Harlequin ichthyosis (HI). We used homozygosity mapping, whole-exome and direct sequencing to delineate the relative distribution of pathogenic variants as well as identify genotype-phenotype correlations in a cohort of 62 Middle Eastern families with ARCI of various ethnic backgrounds. Pathogenic variants were identified in most ARCI-associated genes including TGM1 (21%), CYP4F22 (18%), ALOX12B (14%), ABCA12 (10%), ALOXE3 (6%), NIPAL4 (5%), PNPLA1 (3%), LIPN (2%) and SDR9C7 (2%). In 19% of cases, no mutation was identified. Our cohort revealed a higher prevalence of CYP4F22 and ABCA12 pathogenic variants and a lower prevalence of TGM1 and NIPAL4 variants, as compared to data obtained in other regions of the world. Most variants (89%) in ALOX12B were associated with CIE and were the most common cause of ARCI among patients of Muslim origin (26%). Palmoplantar keratoderma associated with fissures was exclusively a result of pathogenic variants in TGM1. To our knowledge, this is the largest cohort study of ARCI in the Middle-Eastern population reported to date. Our data demonstrate the importance of population-tailored mutation screening strategies and shed light upon specific genotype-phenotype correlations.

[TRENDS IN HOSPITALIZATION OF CHILDREN WITH HENOCH -SCHONLEIN PURPURA].

BACKGROUND: Traditionally, most children diagnosed with Henoch-Schonlein Purpura (HSP) were hospitalized. This policy gradually changed towards selective hospitalization, yet there are still no criteria for admitting pediatric patients with HSP. OBJECTIVES: To examine the clinical features and criteria for hospitalization of pediatric patients with HSP. METHODS: A retrospective analysis was conducted of medical records of pediatric patients with HSP examined in the emergency department (ED) of Schneider Children's Medical Center, during 2005-2015. We compared children who were admitted with those not admitted to the hospital. RESULTS: During the study period, 116 children diagnosed with HSP were examined in the ED of Schneider Children's Medical Center: 14(12%) were admitted at first referral, and 22 (19%) of the children were hospitalized subsequently. The average age of all the children with HSP was 7.4 years, 57% were boys, and approximately 10% of the children had additional diseases, most of them auto-inflammatory. The main indications for hospitalization were gastrointestinal involvement (abdominal pain or bleeding), renal involvement (hematuria or proteinuria), and inability to walk. Most of these symptoms were also present in the children who were not admitted. CONCLUSIONS: Approximately 30% of the children were admitted to the hospital, most of them not at first referral. No clear criteria for admission were found, except for gastrointestinal bleeding.

Disruption of Thrombocyte and T Lymphocyte Development by a Mutation in ARPC1B.

Regulation of the actin cytoskeleton is crucial for normal development and function of the immune system, as evidenced by the severe immune abnormalities exhibited by patients bearing inactivating mutations in the Wiskott-Aldrich syndrome protein (WASP), a key regulator of actin dynamics. WASP exerts its effects on actin dynamics through a multisubunit complex termed Arp2/3. Despite the critical role played by Arp2/3 as an effector of WASP-mediated control over actin polymerization, mutations in protein components of the Arp2/3 complex had not previously been identified as a cause of immunodeficiency. Here, we describe two brothers with hematopoietic and immunologic symptoms reminiscent of Wiskott-Aldrich syndrome (WAS). However, these patients lacked mutations in any of the genes previously associated with WAS. Whole-exome sequencing revealed a homozygous 2 bp deletion, n.c.G623DEL-TC (p.V208VfsX20), in Arp2/3 complex component ARPC1B that causes a frame shift resulting in premature termination. Modeling of the disease in zebrafish revealed that ARPC1B plays a critical role in supporting T cell and thrombocyte development. Moreover, the defects in development caused by ARPC1B loss could be rescued by the intact human ARPC1B ortholog, but not by the p.V208VfsX20 variant identified in the patients. Moreover, we found that the expression of ARPC1B is restricted to hematopoietic cells, potentially explaining why a mutation in ARPC1B has now been observed as a cause of WAS, whereas mutations in other, more widely expressed, components of the Arp2/3 complex have not been observed.

[THE DISEASE OF JOB].

INTRODUCTION: In 1966, Davis et al. coined the term "Job Syndrome", reporting on a new pediatric immunodeficiency disease characterized by "cold" staphylococcal abscesses. This term is widely used in association with several immunodeficiencies with very high levels of IgE, which are also known as "Hyperimmunoglobulin E Syndromes". The assumed similarity between the biblical disease of Job and the "new" immunodeficiency was probably due to the King James' classical translation of the Bible (in 1611), wherein the disease of Job (biblically termed as "Shin") was translated as "boils". However, the biblical word "Shin" is a general term for skin disease or dermatitis, and according to the Talmud, there are 24 different skin diseases called "Shin". New scientific data states that hyper-IgE syndromes are genetic and not acquired (as was in the biblical disease of Job). Therefore, in view of the stigma associated with the name and story of Job, it is recommended to abandon the name of "Job syndrome" and refer to the immune disorders by their genetic source, such as "STAT 3 disease" or "DOCK 8 disease".

IRAK-4- and MyD88-dependent pathways are essential for the removal of developing autoreactive B cells in humans.

Most autoreactive B cells are normally counterselected during early B cell development. To determine whether Toll-like receptors (TLRs) regulate the removal of autoreactive B lymphocytes, we tested the reactivity of recombinant antibodies from single B cells isolated from patients deficient for interleukin-1 receptor-associated kinase 4 (IRAK-4), myeloid differentiation factor 88 (MyD88), and UNC-93B. Indeed, all TLRs except TLR3 require IRAK-4 and MyD88 to signal, and UNC-93B-deficient cells are unresponsive to TLR3, TLR7, TLR8, and TLR9. All patients suffered from defective central and peripheral B cell tolerance checkpoints, resulting in the accumulation of large numbers of autoreactive mature naive B cells in their blood. Hence, TLR7, TLR8, and TLR9 may prevent the recruitment of developing autoreactive B cells in healthy donors. Paradoxically, IRAK-4-, MyD88-, and UNC-93B-deficient patients did not display autoreactive antibodies in their serum or develop autoimmune diseases, suggesting that IRAK-4, MyD88, and UNC-93B pathway blockade may thwart autoimmunity in humans.

Serum Tumor Necrosis Factor-Alpha Levels in Children with Nephrotic Syndrome: A Pilot Study.

BACKGROUND: Several studies link the pathogenesis of nephrotic syndrome to tumor necrosis factor-alpha (TNFα). However, data on the serum TNFα level in children with nephrotic syndrome are sparse. OBJECTIVES: To investigate serum TNFα levels and the effect of steroid therapy in children with nephrotic syndrome. METHODS: A prospective cohort pilot study of children with nephrotic syndrome and controls was conducted during a 1 year period. Serum TNFα levels were measured at presentation and at remission, or after a minimum of 80 days if remission was not achieved. RESULTS: Thirteen patients aged 2-16 years with nephrotic syndrome were compared with 12 control subjects. Seven patients had steroid-sensitive and six had steroid-resistant nephrotic syndrome. Mean baseline serum TNFα level was significantly higher in the steroid-resistant nephrotic syndrome patients than the controls (6.13 pg/ml vs. 4.36 pg/ml, P = 0.0483). Mean post-treatment TNFα level was significantly higher in the steroid-resistant than in the steroid-sensitive nephrotic syndrome patients (5.67 pg/ml vs. 2.14 pg/ml, P = 0.001). In the steroid-resistant nephrotic syndrome patients, mean serum TNFα levels were similar before and after treatment. CONCLUSIONS: Elevated serum TNFα levels are associated with a lack of response to corticosteroids. Further studies are needed to investigate the role of TNFα in the pathogenesis of nephrotic syndrome.

A congenital neutrophil defect syndrome associated with mutations in VPS45.

BACKGROUND: Neutrophils are the predominant phagocytes that provide protection against bacterial and fungal infections. Genetically determined neutrophil disorders confer a predisposition to severe infections and reveal novel mechanisms that control vesicular trafficking, hematopoiesis, and innate immunity. METHODS: We clinically evaluated seven children from five families who had neutropenia, neutrophil dysfunction, bone marrow fibrosis, and nephromegaly. To identify the causative gene, we performed homozygosity mapping using single-nucleotide polymorphism arrays, whole-exome sequencing, immunoblotting, immunofluorescence, electron microscopy, a real-time quantitative polymerase-chain-reaction assay, immunohistochemistry, flow cytometry, fibroblast motility assays, measurements of apoptosis, and zebrafish models. Correction experiments were performed by transfecting mutant fibroblasts with the nonmutated gene. RESULTS: All seven affected children had homozygous mutations (Thr224Asn or Glu238Lys, depending on the child's ethnic origin) in VPS45, which encodes a protein that regulates membrane trafficking through the endosomal system. The level of VPS45 protein was reduced, as were the VPS45 binding partners rabenosyn-5 and syntaxin-16. The level of ß1 integrin was reduced on the surface of VPS45-deficient neutrophils and fibroblasts. VPS45-deficient fibroblasts were characterized by impaired motility and increased apoptosis. A zebrafish model of vps45 deficiency showed a marked paucity of myeloperoxidase-positive cells (i.e., neutrophils). Transfection of patient cells with nonmutated VPS45 corrected the migration defect and decreased apoptosis. CONCLUSIONS: Defective endosomal intracellular protein trafficking due to biallelic mutations in VPS45 underlies a new immunodeficiency syndrome involving impaired neutrophil function. (Funded by the National Human Genome Research Institute and others.).

Nonbullous Erythema Multiforme in Hospitalized Children: A 10-Year Survey.

BACKGROUND: Nonbullous erythema multiforme (NBEM) is an acute, immune-mediated, self-limiting skin disease with distinctive target lesions. Its pathogenesis is unclear, but most cases are considered to be infection related or drug related. In adults, the main precipitating factor is infection. This study reviewed a 10-year experience with hospitalized children with NBEM in a tertiary pediatric medical center in Israel with a focus on precipitating factors. METHODS: The medical files of all children hospitalized from 2001 to 2011 with the diagnosis of NBEM were reviewed. RESULTS: Ninety-seven patients (55 boys and 42 girls) met the inclusion criteria. The mean age was 4.0 years. At least one precipitating factor was recognized in 72 cases; the remainders were classified as idiopathic. The most common factor was drugs (n = 45), particularly penicillin (n = 30), followed by infection with various pathogens (n = 27) including Epstein-Barr virus (7), group A Streptococcus (n = 6), Mycoplasma pneumoniae (n = 5) and herpes simplex virus (n = 4). Analysis according to age showed that medication was the most common precipitating factor in the first year of life, and infection was as common as drugs in the older age groups (1-18 years). CONCLUSIONS: Unlike adult NBEM, the majority of pediatric NBEM is associated with medications, especially penicillin. This may be due to the frequent use of antibiotics in children.

Variable clinical expressivity of STAT3 mutation in hyperimmunoglobulin E syndrome: genetic and clinical studies of six patients.

BACKGROUND AND PURPOSE: Autosomal dominant Hyper IgE syndrome (AD-HIES) is a rare and complex primary immunodeficiency that affects multiple systems. Mutations in signal transducer and activator of transcription 3 (STAT3) gene cause AD-HIES. These mutations have a dominant-negative effect and the presence of such mutations is associated with a clinical phenotype. We aim to describe genetic and clinical characteristics of patients with AD-HIES in our clinic and to highlight the variability of clinical patterns in the same family. METHODS: We describe six patients, four individuals of the same family and two unrelated patients. All patients were given a clinical score based on disease phenotype according to the National Institute of Health (NIH) score. Mutation analysis of STAT3 was done by PCR amplification of all coding exons followed by bidirectional sequencing using the BigDye kit v1.1 and an ABI3700 genetic analyzer (Applied Biosystems). RESULTS: All six patients had DNA binding region point mutations: a proband and his three children with p.Phe384Leu mutation, a patient with p.Arg382Trp substitution and a patient with p.Arg382Gln mutation. All of these mutations were previously reported. Patients differed in infectious, immunologic and somatic features. We observed an extreme variability in disease phenotype within the reported family with one genetically affected patient displaying an 'unaffected' phenotype. CONCLUSIONS: Although the genetic cause of AD-HIES is known, more studies are required to better understand the possible additional factors that may affect disease expressivity within families and the clinical diversity of the disease.

IgM+IgD+CD27+ B cells are markedly reduced in IRAK-4-, MyD88-, and TIRAP- but not UNC-93B-deficient patients.

We studied the distribution of peripheral B-cell subsets in patients deficient for key factors of the TLR-signaling pathways (MyD88, TIRAP/MAL, IL-1 receptor-associated kinase 4 [IRAK-4], TLR3, UNC-93B, TRIF). All TLRs, except TLR3, which signals through the TRIF adaptor, require MyD88 and IRAK-4 to mediate their function. TLR4 and the TLR2 heterodimers (with TLR1, TLR6, and possibly TLR10) require in addition the adaptor TIRAP, whereas UNC-93B is needed for the proper localization of intracellular TLR3, TLR7, TLR8, and TLR9. We found that IgM(+)IgD(+)CD27(+) but not switched B cells were strongly reduced in MyD88-, IRAK-4-, and TIRAP-deficient patients. This defect did not appear to be compensated with age. However, somatic hypermutation of Ig genes and heavy-chain CDR3 size distribution of IgM(+)IgD(+)CD27(+) B cells were not affected in these patients. In contrast, the numbers of IgM(+)IgD(+)CD27(+) B cells were normal in the absence of TLR3, TRIF, and UNC-93B, suggesting that UNC-93B-dependent TLRs, and notably TLR9, are dispensable for the presence of this subset in peripheral blood. Interestingly, TLR10 was found to be expressed at greater levels in IgM(+)IgD(+)CD27(+) compared with switched B cells in healthy patients. Hence, we propose a role for TIRAP-dependent TLRs, possibly TLR10 in particular, in the development and/or maintenance of IgM(+)IgD(+)CD27(+) B cells in humans.

Molecular analysis of a series of Israeli families with Comèl-Netherton syndrome.

BACKGROUND: Comèl-Netherton syndrome is a rare congenital autosomal recessive disorder characterized by congenital ichthyosis, hair shaft abnormalities and atopic diathesis. It is caused by mutations in SPINK5, which encodes the serine protease inhibitor LEKTI. OBJECTIVES: To delineate the spectrum of mutations carried by a series of Israeli patients in an attempt to establish an effective diagnostic strategy for this disease in Israel. METHODS: Mutations were identified by direct sequencing of the entire coding sequence of SPINK5 and confirmed using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Three mutations were identified in seven families, of which two were novel. All mutations were predicted to result in premature termination of protein translation. CONCLUSIONS: This report presents the first case series of patients affected with Comèl-Netherton syndrome in Israel and suggests that some mutations reoccur in a substantial portion of cases in our country, a fact that should be taken into consideration when designing molecular analysis in new cases.

Thymic function in MHC class II-deficient patients.

BACKGROUND: MHC class II (MHC-II) molecules play a pivotal role in the development, activation, and homeostasis of CD4(+) TH cells in the thymus. The absence of MHC-II molecules causes severe T-cell immunodeficiency. OBJECTIVE: We sought to study thymic function, including T-cell receptor excision circle (TREC) quantification, in patients with MHC-II deficiency. METHODS: Eight MHC-II-deficient patients underwent a thorough T-cell immunologic work-up, including thymic activity, which was estimated based on TREC levels and T-cell receptor (TCR) genes, as well as analysis of several sequential human TCR gene rearrangements. RESULTS: In vitro responses to mitogens were normal or only slightly reduced, and flow cytometric evaluations of the TCR-Vß repertoires of total CD3(+) lymphocytes were normal in all patients. However, both the flow cytometric evaluation of the TCR-Vß repertoire on CD4(+) cells and spectratyping evaluation of the TCR-Vγ repertoire on total CD3(+) lymphocytes showed clonal abnormalities. TRECs were present in all patients in both total lymphocytes and sorted CD4(+) cells. Additionally, TRECs were detected in genomic DNA obtained from Guthrie cards with dried blood spots. Quantitative RT-PCR assessment of different TCR gene rearrangement events revealed lower levels in MHC-II-deficient patients compared with levels seen in healthy control subjects. This was irrespective of the total lymphocyte numbers, suggesting a reduced global thymic activity. CONCLUSIONS: Our report highlights potential pitfalls in diagnosing MHC-II deficiency and emphasizes the probable importance of MHC-II molecules in the normal thymic maturation process of T cells. Patients with MHC-II deficiency have detectable TRECs and might therefore be missed by a TREC-based newborn screening program.

Medical And Surgical Management Of Orbital Cellulitis In Children.

OBJECTIVE: The purpose of this study was to identify features of orbital cellulitis that predict response to conservative treatment without surgical intervention and factors associated with a decision for surgery. PATIENTS AND METHODS: The medical files of patients diagnosed with orbital cellulitis at a tertiary medical center in central Israel between 1995 and 2010 were reviewed for clinical data, diagnosis, complications, and type of treatment. Comparison was made between patients treated with antibiotics and patients treated with antibiotics and surgery. RESULTS: Fifty-one patients (35 male) with a mean age of 6.1 years were identified. Main clinical signs included fever (mean 38.5°C), proptosis (82.3%), extraocular motility restriction (74.5%), and ocular pain (41.1%). Forty-one patients were successfully treated with antibiotics and 10 required endoscopic sinus surgery. On between-group comparison, the surgery group had severe eye pain (p = 0.009), severe proptosis (P = 0.02), longer intravenous antibiotic treatment (13.2 vs. 9.2 days, p = 0.04), and several imaging findings. Additional factors associated with surgical intervention included older children, subperiorbital abscess, larger dimension of the abscess (mean 15 mm), involvement of frontal sinuses and findings of intraorbital air bubbles. There was no visual deterioration in either group and no late sequelae. CONCLUSION: Factors associated with surgery included age older than 9 years, severe ocular pain, severe proptosis, and subperiorbital large abscess. These may be used for early identification of patients at risk of failure of only medical management.

IL-12Rß1 deficiency: mutation update and description of the IL12RB1 variation database.

IL-12Rß1 deficiency is an autosomal recessive disorder characterized by predisposition to recurrent and/or severe infections caused by otherwise poorly pathogenic mycobacteria and salmonella. IL-12Rß1 is a receptor chain of both the IL-12 and the IL-23 receptor and deficiency of IL-12Rß1 thus abolishes both IL-12 and IL-23 signaling. IL-12Rß1 deficiency is caused by bi-allelic mutations in the IL12RB1 gene. Mutations resulting in premature stop codons, such as nonsense, frame shift, and splice site mutations, represent the majority of IL-12Rß1 deficiency causing mutations (66%; 46/70). Also every other morbid mutation completely inactivates the IL-12Rß1 protein. In addition to disease-causing mutations, rare and common variations with unknown functional effect have been reported in IL12RB1. All these variants have been deposited in the online IL12RB1 variation database (www.LOVD.nl/IL12RB1). In this article, we review the function of IL-12Rß1 and molecular genetics of human IL12RB1.

Selective predisposition to bacterial infections in IRAK-4-deficient children: IRAK-4-dependent TLRs are otherwise redundant in protective immunity.

Human interleukin (IL) 1 receptor-associated kinase 4 (IRAK-4) deficiency is a recently discovered primary immunodeficiency that impairs Toll/IL-1R immunity, except for the Toll-like receptor (TLR) 3- and TLR4-interferon (IFN)-alpha/beta pathways. The clinical and immunological phenotype remains largely unknown. We diagnosed up to 28 patients with IRAK-4 deficiency, tested blood TLR responses for individual leukocyte subsets, and TLR responses for multiple cytokines. The patients' peripheral blood mononuclear cells (PBMCs) did not induce the 11 non-IFN cytokines tested upon activation with TLR agonists other than the nonspecific TLR3 agonist poly(I:C). The patients' individual cell subsets from both myeloid (granulocytes, monocytes, monocyte-derived dendritic cells [MDDCs], myeloid DCs [MDCs], and plasmacytoid DCs) and lymphoid (B, T, and NK cells) lineages did not respond to the TLR agonists that stimulated control cells, with the exception of residual responses to poly(I:C) and lipopolysaccharide in MDCs and MDDCs. Most patients (22 out of 28; 79%) suffered from invasive pneumococcal disease, which was often recurrent (13 out of 22; 59%). Other infections were rare, with the exception of severe staphylococcal disease (9 out of 28; 32%). Almost half of the patients died (12 out of 28; 43%). No death and no invasive infection occurred in patients older than 8 and 14 yr, respectively. The IRAK-4-dependent TLRs and IL-1Rs are therefore vital for childhood immunity to pyogenic bacteria, particularly Streptococcus pneumoniae. Conversely, IRAK-4-dependent human TLRs appear to play a redundant role in protective immunity to most infections, at most limited to childhood immunity to some pyogenic bacteria.

Reduced bone density in patients with autosomal dominant hyper-IgE syndrome.

BACKGROUND AND PURPOSE: Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare primary immunodeficiency disorder . It has been recognized as a multisystem disorder and is characterized by both immunologic and non-immunologic manifestations. Possible bone involvement in autosomal dominant HIES include fractures, scoliosis, cystic bone changes, and osteopenia. We sought to evaluate the changes in bone density in adolescents and young adults with AD-HIES, mostly with proven STAT3 mutation, followed in our institute. METHODS: We studied eight patients with AD-HIES who attended our immunology clinic. All patients underwent at least one bone mass dual-energy x-ray absorptiometry assessment (dual-energy x-ray absorptiometry scan).These findings were evaluated. RESULTS: The age of the patients at the time of their first bone density scan ranged between 10 and 24 years (mean 16.1 ± 4.0 years); the duration of follow-up was 4-11 years (mean 5.8 ± 3.5 years). Four patients had a history of fractures. Mean Z score in these patients was -1.8 ± 0.7. For three patients, Z score was below -1. The other four patients had no history of fractures. Mean Z score in these patients was -0.9 ± 0.5. Only one patient in this group had a Z score below -1. Bone density was below average in all patients; mean spinal Z score was -1.6 ± 0.4. Four patients were followed through the second decade, and all showed progressive deterioration in bone density. Three were treated with alendronate sodium, with improvement in the bone scan results. CONCLUSIONS: Bone density decreases considerably over time in adolescents and young adults suffering from AD- HIES. Treatment with alendronate sodium may be effective in alleviating osteopenia.

Autoimmunity and cystatin SA1 deficiency behind chronic mucocutaneous candidiasis in autoimmune polyendocrine syndrome type 1.

Patients with the monogenic disease autoimmune polyendocrine syndrome type I (APSI) develop autoimmunity against multiple endocrine organs and suffer from chronic mucocutaneous candidiasis (CMC), a paradoxical complication with an unknown mechanism. We report here that saliva from APSI patients with CMC is defective in inhibiting growth of Candida albicans in vitro and show reduced levels of a salivary protein identified as cystatin SA1. In contrast, APSI patients without CMC express salivary cystatin SA1 and can inhibit C. albicans to the same extent as healthy controls. We evaluated the anti-fungal activity of cystatin SA1 and found that synthesized full length cystatin SA1 efficiently inhibits growth of C. albicans in vitro. Moreover, APSI patients exhibit salivary IgA autoantibodies recognizing myosin-9, a protein expressed in the salivary glands, thus linking autoimmunity to cystatin SA1 deficiency and CMC. This data suggests an autoimmune mechanism behind CMC in APSI and provides rationale for evaluating cystatin SA1 in antifungal therapy.

Newborn screening for severe T and B cell immunodeficiency in Israel: a pilot study.

BACKGROUND: Enumeration of T cell receptor excision circles (TREC) was recently adopted as a neonatal screening assay for severe combined immunodeficiency (SCID). Enumeration of kappa-deleting recombination excision circle (KREC) copy numbers can be similarly used for early assessment of B cell lymphopenia. OBJECTIVE: To assess the ability of TREC and KREC counts to identify patients with combined T and B cell immunodeficiency in a pilot study in Israel. METHODS: We studied seven children born in Israel during the years 2010-2011 and later diagnosed with SCID, and an additional patient with pure B cell immunodeficiency. TREC and KREC in peripheral blood upon diagnosis and in their neonatal Guthrie cards were analyzed using real-time quantitative polymerase chain reaction, as were Guthrie cards with dried blood spots from healthy newborns and from normal and SCID-like controls. RESULTS: The first features suggestive of SCID presented at age 3.1 +/- 2.4 months in all patients. Yet, the diagnosis was made 4.1 +/- 2.9 months later. Their TREC were undetectable or significantly low at their clinical diagnosis and in their originally stored Guthrie cards, irrespective of the amount of their circulating T cells. KREC were undetectable in six SCID patients who displayed B cell lymphopenia in addition to T cell lymphopenia. KREC were also undetectable in one patient with pure B cell immunodeficiency. CONCLUSIONS: TREC and KREC quantification are useful screening tests for severe T and B cell immunodeficiency. Implementation of these tests is highly important especially in countries such as Israel where a high frequency of consanguinity is known to exist.