In vitro functional analysis of four variants of human asparagine synthetase.

The loss-of-function variants of the human asparagine synthetase (ASNS) gene cause asparagine synthetase deficiency (ASNSD). Diagnosis of ASNSD requires genetic tests because a specific biochemical diagnostic for ASNSD is not available. There are a few reports describing the functional evaluation of ASNS variants. Therefore, in vitro methods are needed to evaluate the detected variants in patients. In this report, five types of human ASNS proteins (wild-type and our reported four variants: p.Leu145Ser, p.Leu247Trp, p.Val489Asp, and p.Trp541Cysfs*5) were expressed in silkworm using a baculoviral expression system. An enzymatic activity assay of ASNS was performed, and the concentration of asparagine by ninhydrin and High Performance Liquid Chromatography methods using the purified recombinant proteins was measured. We established ASNS deficient HEK293 cells using the CRISPR/Cas9 method and evaluated the growth of cells without asparagine after transduction of ASNS variants with a lentiviral expression system. The four ASNS variants displayed significantly low enzymatic activity. The ASNS deficient HEK293 cells transduced with wild-type ASNS grew without asparagine, whereas cells transduced with the variants did not grow or showed significantly slower growth than cells transduced with wild-type ASNS. Herein, we established a method for evaluating the enzymatic activity of the recombinant human ASNS variants. The results of the cell-based assay corroborated the results of the enzymatic activity. These methods should enable the evaluation of the pathogenicity of ASNS variants.

Immunophenotyping of A20 haploinsufficiency by multicolor flow cytometry.

Haploinsufficiency of A20 (HA20) causes inflammatory disease resembling Behçet's disease; many cases have been reported, including some that are complicated with autoimmune diseases. This study aims to clarify the immunophenotype of patients with HA20 by analyzing lymphocyte subsets using multicolor flow cytometry. The patients with HA20 previously diagnosed in a nationwide survey were compared by their cell subpopulations. In total, 27 parameters including regulatory T cells (Tregs), double-negative T cells (DNTs), and follicular helper T cells (TFHs) were analyzed and compared with the reference values in four age groups: 0-1, 2-6, 7-19, and ≥20 years. The Tregs of patients with HA20 tended to increase in tandem with age-matched controls at all ages. In addition, patients ≥20 years had increased DNTs compared with controls, whereas TFHs significantly increased in younger patients. In HA20 patients, the increase in DNTs and TFHs may contribute to the development of autoimmune diseases.

Immunologic Effects of Sirolimus in Patients With Vascular Anomalies.

Emerging data have suggested that sirolimus may be a treatment option for complicated vascular anomalies (VAs). The present study aimed to investigate the immunologic effects of sirolimus treatment for 6 months in patients with VAs. Blood samples obtained from the patients enrolled in 2 multicenter studies to investigate the efficacy of sirolimus for VAs before and after sirolimus treatment for 6 months were used. Data for total white blood cell count, absolute lymphocyte count, serum immunoglobulins (Igs) levels (IgG, IgA, IgM), lymphocyte proliferation assays with mitogens including phytohemagglutinin and concanavalin A, and flow cytometric analysis of lymphocyte subsets were evaluated. A total of 18 patients with VAs receiving sirolimus treatment were included in the study. Comparisons of white blood cell, absolute lymphocyte count, IgG, IgA, IgM, and reaction rates of phytohemagglutinin and concanavalin A revealed no significant differences before and after treatment. No significant differences were observed in the absolute counts of lymphocyte subtypes before and after treatment, except for regulatory T-cell counts, which were significantly decreased after treatment. Severe infections were not observed during sirolimus treatment. The immunologic parameters assessed in the present study were hardly affected by sirolimus treatment for 6 months in patients with VAs.

Evading the AAV Immune Response in Mucopolysaccharidoses.

The humoral immune response elicited by adeno-associated virus (AAV)-mediated gene therapy for the treatment of mucopolysaccharidoses (MPS) poses a significant challenge to achieving therapeutic levels of transgene expression. Antibodies targeting the AAV capsid as well as the transgene product diminish the production of glycosaminoglycan (GAG)-degrading enzymes essential for the treatment of MPS. Patients who have antibodies against AAV capsid increase in number with age, serotype, and racial background and are excluded from the clinical trials at present. In addition, patients who have undergone AAV gene therapy are often excluded from the additional AAV gene therapy with the same serotype, since their acquired immune response (antibody) against AAV will limit further efficacy of treatment. Several methods are being developed to overcome this immune response, such as novel serotype design, antibody reduction by plasmapheresis and immunosuppression, and antibody evasion using empty capsids and enveloped AAV vectors. In this review, we examine the mechanisms of the anti-AAV humoral immune response and evaluate the strengths and weaknesses of current evasion strategies in order to provide an evidence-based recommendation on evading the immune response for future AAV-mediated gene therapies for MPS.

Potential biomarkers of kaposiform lymphangiomatosis.

BACKGROUND: Kaposiform lymphangiomatosis (KLA) has recently been distinguished as a novel subtype of generalized lymphatic anomaly (GLA), and is characterized by foci of spindle endothelial cells amid a background of malformed lymphatic channels. The etiology of these diseases remains unknown and diagnosis is confounded by their similar clinical findings. This study aimed to clarify differences in the clinical findings and plasma cytokine profiles of GLA and KLA patients. PROCEDURE: Clinical features data of GLA and KLA patients were obtained from a national survey. Differences in clinical findings, plasma levels of cytokines, and survival were analyzed. Plasma was obtained from healthy controls and GLA and KLA patients. Thirty-six angiogenic and lymphangiogenic factors were evaluated for cytokine concentration. RESULTS: Twenty-one patients with GLA and 11 with KLA were recruited. Mediastinal masses, hemorrhagic pericardial and pleural effusion, coagulation disorders, and thrombocytopenia were more frequent in KLA than in GLA. KLA had a significantly poorer outcome than GLA (P = 0.044). Soluble VEGFR3, angiopoietin 2, HGF, soluble HER2, tenascin C, and soluble HGFR levels were higher in KLA. Notably, soluble VEGFR3 and angiopoietin 2 levels were approximately 10-fold higher than those of other molecules measured. However, soluble VEGFR1 and soluble TIE2 were lower in KLA than in GLA and the controls. CONCLUSIONS: Patients with KLA have an unfavorable prognosis and serious symptoms (hemorrhagic pleural effusion and coagulation disorders). Our data indicate that eight angiogenic cytokines might be potential biomarkers of KLA.

A Heterozygous CFHR3-CFHR1 Gene Deletion in a Pediatric Patient With Transplant-associated Thrombotic Microangiopathy Who was Treated With Eculizumab.

Complement system dysregulation, such as complement Factor H (CFH) autoantibodies and deletions in CFH-related (CFHR) genes 3 and 1, might cause transplant-associated thrombotic microangiopathy (TA-TMA). The use of eculizumab, a terminal complement inhibitor, could be a targeted therapy for TA-TMA. We report a 1-year-old girl who developed TA-TMA, just after autologous peripheral blood stem cell transplantation in neuroblastoma therapy. Eculizumab improved TA-TMA. Investigation for the complement alternative pathway showed a heterozygous CFHR3-CFHR1 gene deletion, which is involved in complement activation. The patient might develop TA-TMA as a result of complement regulatory gene mutation.

Immunodeficiency in Two Female Patients with Incontinentia Pigmenti with Heterozygous NEMO Mutation Diagnosed by LPS Unresponsiveness.

PURPOSE: Anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID) is caused by mutations in the NF-κB essential modulator (NEMO) or NF-κB inhibitor, alpha (IKBA) genes. A heterozygous NEMO mutation causes incontinentia pigmenti (IP) in females, while a hemizygous hypomorphic mutation of NEMO causes EDA-ID in males. In general, immunodeficiency is not shown in IP patients. Here, we investigated two female patients with IP and immunodeficiency. METHODS: The patients were initially suspected to have IRAK4 deficiency and Mendelian susceptibility to mycobacterial disease, respectively, because of recurrent pneumonia with delayed umbilical cord detachment or disseminated mycobacterial infectious disease. We measured tumor necrosis factor (TNF)-α production and performed mutation screening. RESULTS: The TNF-α production from lipopolysaccharide (LPS)-stimulated CD14-positive cells was partially defective in both female patients. A genetic analysis showed them to carry the heterozygous NEMO mutations c.1167_1168insC or c.1192C>T. Although NEMO mutations in IP patients are typically eliminated by X-inactivation skewing, an analysis of cDNA obtained from the somatic cells of the patients showed the persistence of these mutations in peripheral blood mononuclear cells and peripheral granulocytes. A NF-κB reporter gene analysis using NEMO-deficient HEK293 cells showed the loss of NF-κB activity in these NEMO mutants, while the NF-κB protein expression levels by the NEMO mutants were consistent with those of wild-type NEMO. CONCLUSIONS: The delayed skewing of the mutant allele may be responsible for the observed innate immune defect in these patients. The detection of LPS unresponsiveness is suitable for identifying female IP patients with immunodeficiency.

Detection of ovomucoid-specific low-affinity IgE in infants and its relationship to eczema.

BACKGROUND: Allergen-specific low-affinity IgE was previously detected in cord blood by a highly sensitive densely carboxylated protein (DCP) chip, but not by ImmunoCAP. Here, we investigated the presence of low-affinity IgE during the early life of infants and observed its relationship with eczema. METHODS: We conducted a birth cohort study, collecting sera at birth and 6 and 14 months of age (n = 110). We monitored the ovomucoid (OM)- and egg white (EW)-specific IgE (sIgE) by ImmunoCAP or DCP chip and analyzed the antigen affinity of sIgE by binding inhibition assays in the presence or absence of a mild chaotropic agent, diethyl amine (DEA). The low- and high-affinity OM-sIgEs and sensitization risk factors were analyzed by a multivariate logistic analysis. RESULTS: The OM-sIgE measured by DCP chip significantly correlated with that measured by ImmunoCAP, but some samples assessed as OM-sIgE positive by DCP chip were considered OM-sIgE negative by ImmunoCAP. Binding inhibition analysis after DEA treatment was performed for participants judged as OM-sIgE positive by DCP chip at 14 M. The group assessed as negative for OM- and EW-sIgE by ImmunoCAP at 6 and 14 months showed a larger binding inhibition curve shift after DEA treatment than did the group assessed as positive at these times, indicating the presence of low-affinity sIgE antibodies at 14 months. The logistic regression analysis found that persistent eczema from 6 to 14 months is a significant risk factor for developing high-affinity, but not low-affinity, sIgE. CONCLUSIONS: Human infant peripheral blood contains allergen-specific low-affinity sIgE. Persistent eczema is related to the development of high-affinity, but not low-affinity, IgE.

Prepubertal onset of slipped capital femoral epiphysis associated with hypothyroidism: a case report and literature review.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is a common hip disorder characterized by displacement of the capital femoral epiphysis from the metaphysic through the femoral epiphyseal plate. SCFE usually occurs during puberty, with obesity a common risk factor. We experienced a rare case of SCFE associated with hypothyroidism in a prepubescent patient who was not obese. CASE PRESENTATION: The patient was an 8-year-old boy suffering from bilateral SCFE with hypothyroidism. The patient's growth had started to slow at 4 years of age, and at 8 years he was of short stature. During his evaluation for SCFE management, primary hypothyroidism was diagnosed due to the presence of anti-thyroid peroxidase and anti-thyroglobulin antibodies. After the patient was treated for hypothyroidism, which improved his thyroid function, surgery was performed for bilateral SCFE. CONCLUSIONS: Among the 42 patients with SCFE associated with hypothyroidism in the literature, most SCFE occurred during puberty or in adults with delayed epiphyseal closure. Only two patients (4.8%), including the present patient, were ≤9 years old. Although being overweight or obese is common for patients with SCFE associated with hypothyroidism (76.0%), it was not observed in the present case. Persistent hypothyroidism, however, may be a risk factor for SCFE even before puberty and without obesity.

T-cell epitope-containing hypoallergenic ß-lactoglobulin for oral immunotherapy in milk allergy.

BACKGROUND: Optimally hydrolyzed ß-Lactoglobulin (ßLg) is a promising milk oral immunotherapy (OIT) candidate with respect to showing reduced B-cell reactivity but retaining the T-cell epitope. To demonstrate that an edible hypoallergenic ßLg hydrolysate containing the T-cell epitope is suitable for OIT. We tested how chymotrypsin affected the retention of the T-cell epitope of ßLg when preparing ßLg hydrolysates using food-grade trypsin. METHODS: We investigated the effect of chymotrypsin activity on the formation of the T-cell epitope-containing peptide of ßLg (ßLg102-124 ) and prepared an edible ßLg hydrolysate containing ßLg102-124 using screened food-grade trypsins. B-cell reactivity was determined using immunoassays in which ELISA was performed with anti-ßLg rabbit IgG and Western blotting was performed with a milk-specific IgE antiserum. RESULTS: In ßLg hydrolysis performed by varying the activity of trypsin and chymotrypsin, chymotrypsin activity inhibited the formation of ßLg102-124 with an increase in hydrolysis time in a dose-dependent manner. ßLg102-124 was generated by two of five food-grade trypsins used at a ratio of 1:50 (w/w, enzyme/substrate) for 20 h at 40°C. The edible ßLg hydrolysate retained ßLg102-124 and showed a reduction in molecular weight distribution and antigenicity against IgG and IgE. CONCLUSIONS: Chymotrypsin activity inhibited the formation of ßLg102-124 in the trypsin hydrolysate of ßLg. This ßLg trypsin hydrolysate is a novel candidate for peptide-based OIT in cow's milk allergy for safely inducing desensitization.

Successful Everolimus Treatment of Kaposiform Hemangioendothelioma With Kasabach-Merritt Phenomenon: Clinical Efficacy and Adverse Effects of mTOR Inhibitor Therapy.

Kasabach-Merritt phenomenon (KMP) is a life-threatening consumptive coagulopathy associated with underlying kaposiform hemangioendothelioma (KHE) in infancy. We describe the case of a 3-month-old girl with KHE complicated by KMP who responded dramatically to treatment with everolimus, a mechanistic target of rapamycin (mTOR) inhibitor. Immunohistochemical expression of mTOR was found in the KHE biopsy specimens, which may explain the improvement of KMP and reduction in KHE tumor size with mTOR inhibitor treatment. This effective use of everolimus may shed light on the emerging role of mTOR signaling in the development and pathogenesis of KHE and KMP.

Propranolol for infantile hemangioma: Effect on plasma vascular endothelial growth factor.

BACKGROUND: Propranolol has recently been shown to be highly effective for infantile hemangioma (IH), but the mechanism of action of propranolol and the usefulness of measurement of vascular endothelial growth factor (VEGF) remain poorly understood. The aim of this study was therefore to determine the efficacy of propranolol treatment and to evaluate changes in plasma VEGF in IH patients who underwent propranolol treatment. METHODS: The study group consisted of 35 children with IH. Oral propranolol was give at a dose of 2.0 mg/kg/day and was divided in three doses. Outcome was assessed using the visual analog scale (VAS) of size and color. Plasma VEGF concentration was analyzed on enzyme-linked immunoabsorbent assay, and compared between the groups. RESULTS: Improvement in VAS in patients who started propranolol before 6 months of age was superior to that in those who started propranolol after 6 months of age. VEGF concentration was significantly correlated with lesion size (P = 0.002), whereas no correlation was observed with age. VEGF concentration 4 weeks after treatment was significantly lower than that before treatment (P < 0.01). CONCLUSIONS: Measurement of VEGF may be a useful tool for predicting the course of IH and monitoring the effectiveness of treatment.

Complete bone regeneration in hemophilic pseudotumor of the mandible.

Hemophilic pseudotumor (HP) is rare, seen in 1-2% of patients with hemophilia, and is extremely uncommon in the mandible. A 6-year-old boy with moderate hemophilia A presented to our hospital with left mandibular swelling. Based on clinical and radiological findings, a tentative diagnosis of HP was made. After factor VIII administration, the lesion was curetted and HP was confirmed on histopathology. The patient was treated with twice-weekly factor VIII until the lesion had completely resolved and bone had regenerated at 1 year. The best treatment for HP is not established; however, appropriate initial treatment and postoperative prophylaxis are effective.

Effectiveness of Medium-Chain Triglyceride Oil Therapy in Two Japanese Citrin-Deficient Siblings: Evaluation Using Oral Glucose Tolerance Tests.

Citrin deficiency, an inherited defect of the liver-type mitochondrial aspartate/glutamate carrier isoform (citrin), may cause impairment of glycolysis because of an increase in the cytosolic NADH/NAD+ ratio. We report a Japanese boy whose main complaint was recurrent hypoglycemic episodes. He was suspected as having citrin deficiency because of his peculiar preference for protein- and fat-rich food. His young sister also had a similar food preference. Both siblings were diagnosed with citrin deficiency by genetic analysis. The brother and sister underwent an oral glucose tolerance test (OGTT) at 10 and 7 yr of age, respectively. Blood glucose, ammonia, lactic acid, pyruvic acid, and insulin levels were monitored before starting the test, and then every 30 min. During this test, they maintained blood glucose levels until 180 min. At 210 min, they experienced vomiting, feeling ill, and decreased blood glucose levels (2.9 and 2.8 mmol/l in the brother and sister, respectively). The sister and brother recovered uneventfully by intravenous glucose injection. In a second OGTT, 4 months after medium-chain triglyceride (MCT) oil supplementation, they had no major symptoms and normal glucose levels were maintained, even after 240 min. Additionally, after MCT oil therapy, their food preference slightly changed as they started eating more carbohydrates. Our OGTT data suggest excess carbohydrate intake has adverse consequences in patients with citrin deficiency, including hypoglycemia after a few hours. MCT oil therapy may be effective in preventing such hypoglycemia and improving metabolic derangement, even during the so-called apparently healthy period.

Amino acid copolymers that alleviate experimental autoimmune encephalomyelitis in vivo interact with heparan sulfates and glycoprotein 96 in APCs.

Multiple sclerosis (MS) is an autoimmune disease that affects the CNS. One approved treatment for relapsing forms of MS is YEAK, a random copolymer of the amino acids tyrosine, glutamic acid, alanine, and lysine. YFAK, a second-generation copolymer composed of tyrosine, phenylalanine, alanine, and lysine, is more successful in treating experimental autoimmune encephalomyelitis, a mouse model of MS. Although originally designed and optimized based on the autoantigen myelin basic protein (MBP) and the MBP-derived peptide MBP85-99 presented to the MS-associated class II MHC molecule HLA-DR2, YEAK and YFAK also stimulate cytokine and chemokine production in APCs that lack class II MHC products. How YEAK and YFAK copolymers interact with APCs remains enigmatic. We used biotinylated YFAK to affinity-purify YFAK-interacting proteins from RAW264.7 cells and tested APCs from mice deficient in several of the newly identified interactors for their capacity to secrete CCL22 in response to YEAK and YFAK. We propose that initial contact of YFAK with cells is mediated mainly by electrostatic interactions, and find that interaction of YFAK with host proteins is strongly dependent on ionic strength. Cells deficient in enzymes involved in sulfation of proteins and proteoglycans showed strongly reduced binding of biotinylated YFAK. Lastly, cells stimulated with YFAK in the presence of heparin, structurally similar to heparan sulfates, failed to produce CCL22. We conclude that charge-dependent interactions of copolymers that alleviate MS/experimental autoimmune encephalomyelitis are critical for their effects exerted on APCs and may well be the main initial mediators of these therapeutically active copolymers.

Successive MRI Findings of Reversible Cerebral White Matter Lesions in a Patient with Cystathionine ß-Synthase Deficiency.

Cystathionine ß-synthase (CBS) deficiency, well known as classical homocystinuria, is a rare autosomal recessive inborn error of homocysteine and sulfur metabolism. CBS converts homocysteine to cystathionine. The clinical features of untreated CBS deficiency include myopia, ectopia lentis, mental retardation, skeletal anomalies resembling Marfan syndrome, and thromboembolic events. Cerebral white matter lesions (CWMLs), identified in magnetic resonance imaging (MRI), are related to various clinical conditions including ischemia, inflammation, demyelination, infection, a tumor, and metabolic disorders such as phenylketonuria. The presence of CWMLs is, however, believed to be a very rare condition in CBS-deficient patients. Herein, we report reversible CWMLs associated with hypermethioninemia caused by poor protein restriction and betaine therapy in a 21-year-old male with pyridoxine-nonresponsive CBS deficiency. T2-weighted images (T2WI) and fluid-attenuated inversion-recovery (FLAIR) images showed diffuse high signal intensity in subcortical areas extending to the deep white matter. Diffusion-weighted images (DWI) showed high signal intensity, while apparent diffusion coefficient (ADC) map demonstrated decreased ADC value in the lesions. The course of improvement after correct methionine restriction was successively followed by brain MRI. The CWMLs had regressed at 1 month after restriction, and disappeared after 5 months. ADC values were very low before proper methionine restriction, but normalized after 2 months. Use of betaine in the presence of elevated plasma methionine may increase the risk of reversible CWMLs in some CBS-deficient patients.

Clinical and genetic characterization of Japanese sporadic cases of periodic Fever, aphthous stomatitis, pharyngitis and adenitis syndrome from a single medical center in Japan.

PURPOSE: To investigate clinical presentation, genetic background and cytokine profile of Japanese sporadic cases of periodic fever, aphthous stomatitis, pharyngitis and adenitis (PFAPA) syndrome. METHODS: Nine PFAPA syndrome patients were recruited. DNA sequence analysis of auto inflammatory disorder susceptibility genes, MEFV, MVK, NLRP3, and TNFRSF1A, were performed. Serum cytokine levels and monocyte IL-1ß levels were measured by ELISA. RESULTS: The study population consisted of six males and three females (mean age of onset 26.8 months). Febrile episodes lasted 3-6 days with symptom-free intervals ranging from 2 to 12 weeks. Fever was accompanied by pharyngitis (n = 8), aphthous stomatitis (n = 4), and cervical adenitis (n = 5). White blood cells and C-reactive protein were increased during the attack phase. Mean IgD serum levels were 7.32 ± 9.51 mg/dl during the attack phase, and were mildly elevated in two patients. Heterozygous MEFV, NLRP3 and TNFRSF1A variants were detected in four, one and three cases, respectively. Serum TNF-α and IL-18 levels were elevated during the attack-free and attack periods compared with controls. Other cytokines, IL-1ß, IL-1ra, IL-6, and sTNFR1, were only increased during the attack phase. Oral prednisolone was administered to eight patients and immediately reduced fever. Tonsillectomy performed in five patients induced cessation of fever in four patients. One case with repeated fever attacks after tonsillectomy showed increased monocyte IL-1ß production, similar to the other active case with genetic variants of auto inflammatory disorder-associated genes. CONCLUSIONS: Japanese PFAPA syndrome patients may have cytokine regulation dysfunction as a result of genetic variants of auto inflammatory disorder-associated genes.

The role of dendritic cells in the generation of CD4(+) CD25(HI) Foxp3(+) T cells induced by amino acid copolymers.

The effects of the amino acid copolymers used in the therapy of experimental autoimmune encephalomyelitis, poly(Y,E,A,K)(n) (Copaxone(®)) and poly(Y,F,A,K)(n), on murine myeloid cells have been investigated. After administration of these copolymers to mice, increases in several splenic myeloid cell populations were observed, including CD11b(+) CD11c(+) dendritic cells. The latter were the major splenic cell type that secreted CCL22 (macrophage-derived chemokine) on stimulation with amino acid copolymers. CCL22 secretion was also stimulated from bone marrow-derived dendritic cells (BMDC) generated with GM-CSF in much larger amounts than from bone marrow-derived macrophages generated with M-CSF. Moreover, CCL22 secretion could also be obtained using BMDC generated from two different types of MHC II(-/-) mice, indicating that an innate immune receptor is involved. Finally, incubation of these BMDC or splenic dendritic cells with naive CD4(+) CD25(-) T cells resulted in formation of CD4(+) CD25(HI) Foxp3 T cells (~25% of which were Foxp3(+)). The number of these regulatory cells was doubled by pretreatment of BMDC with amino acid copolymers.