Autoimmunity against melanoma differentiation-associated gene 5 induces interstitial lung disease mimicking dermatomyositis in mice.

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (DM) is characterized by amyopathic DM with interstitial lung disease (ILD). Patients with anti-MDA5 antibody-associated ILD frequently develop rapidly progression and present high mortality rate in the acute phase. Here, we established a murine model of ILD mediated by autoimmunity against MDA5. Mice immunized with recombinant murine MDA5 whole protein, accompanied with complete Freund's adjuvant once a week for four times, developed MDA5-reactive T cells and anti-MDA5 antibodies. After acute lung injury induced by intranasal administration of polyinosinic-polycytidylic acid [poly (I:C)] mimicking viral infection, the MDA5-immunized mice developed fibrotic ILD representing prolonged respiratory inflammation accompanied by fibrotic changes 2 wk after poly (I:C)-administration, while the control mice had quickly and completely recovered from the respiratory inflammation. Treatment with anti-CD4 depleting antibody, but not anti-CD8 depleting antibody, suppressed the severity of MDA5-induced fibrotic ILD. Upregulation of interleukin (IL)-6 mRNA, which was temporarily observed in poly (I:C)-treated mice, was prolonged in MDA5-immunized mice. Treatment with anti-IL-6 receptor antibody ameliorated the MDA5-induced fibrotic ILD. These results suggested that autoimmunity against MDA5 exacerbates toll-like receptor 3-mediated acute lung injury, and prolongs inflammation resulting in the development of fibrotic ILD. IL-6 may play a key role initiating ILD in this model.

Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children.

IMPORTANCE: We characterized Streptococcus pneumoniae serotype 24F sequence type (ST) 162 isolated from Japanese children with invasive pneumococcal disease (IPD). Owing to its highly invasive nature, serotype 24F is expected to be isolated from clinically significant cases. Serotype 24F ST162 isolates tested in the present study did not grow at 35°C in ambient air. Therefore, antimicrobial susceptibility testing using the broth microdilution method, which is usually conducted in ambient air, cannot be performed, posing a clinical challenge. Clinical practitioners and laboratory personnel should be aware of the epidemiological, bacteriological, and molecular characteristics of serotype 24F ST162. We believe that our findings can help diagnose and treat IPD caused by serotype 24F ST162, a serotype expected to become problematic in the post-13 valent pneumococcal conjugate vaccine era.

Reanalysis of Chromosomal Microarray Data Using a Smaller Copy Number Variant Call Threshold Identifies Four Cases with Heterozygous Multiexon Deletions of ARID1B, EHMT1, and FOXP1 Genes.

Introduction: Chromosomal microarray (CMA) is a highly accurate and established method for detecting copy number variations (CNVs) in clinical genetic testing. CNVs are important etiological factors for disorders such as intellectual disability, developmental delay, and multiple congenital anomalies. Recently developed analytical methods have facilitated the identification of smaller CNVs. Therefore, reanalyzing CMA data using a smaller CNV calling threshold may yield useful information. However, this method was left to the discretion of each institution. Methods: We reanalyzed the CMA data of 131 patients using a smaller CNV call threshold: 50 kb 50 probes for gain and 25 kb 25 probes for loss. We interpreted the reanalyzed CNVs based on the most recently available information. In the reanalysis, we filtered the data using the Clinical Genome Resource dosage sensitivity gene list as an index to quickly and efficiently check morbid genes. Results: The number of copy number loss was approximately 20 times greater, and copy number gain was approximately three times greater compared to those in the previous analysis. We detected new likely pathogenic CNVs in four participants: a 236.5 kb loss within ARID1B, a 50.6 kb loss including EHMT1, a 46.5 kb loss including EHMT1, and an 89.1 kb loss within the FOXP1 gene. Conclusion: The method employed in this study is simple and effective for CMA data reanalysis using a smaller CNV call threshold. Thus, this method is efficient for both ongoing and repeated analyses. This study may stimulate further discussion of reanalysis methodology in clinical laboratories.

Targeted temperature management at 36°C is a risk factor for ventilator-associated pneumonia.

BACKGROUND: In contrast to the adult population, limited information is currently available on risk factors for ventilator-associated pneumonia (VAP) in children. Therapeutic hypothermia has been identified as a risk factor for the early onset of VAP in adults; however, the relationship between VAP and normothermia remains unclear. The present study investigated risk factors for VAP in children, with a focus on the deleterious effects of therapeutic normothermia on VAP. METHODS: We retrospectively investigated the clinical characteristics of children treated with mechanical ventilation for more than 48 h and analyzed risk factors for VAP. The endpoint was the onset of VAP by the seventh day after the initiation of mechanical ventilation. RESULTS: Among the 288 patients enrolled, seven (2.4%) developed VAP. No significant differences were observed in clinical backgrounds between the VAP and non-VAP groups. A univariate analysis identified target temperature management (TTM) at 36°C (p < 0.0001) and methylprednisolone (mPSL) pulse therapy (p = 0.02) as risk factors for VAP. An analysis of the time to the onset of VAP by the Kaplan-Meier plot and log-rank test revealed a significantly higher incidence of VAP in the TTM group (p < 0.0001) and mPSL pulse group (p = 0.001). CONCLUSION: TTM at 36°C and mPSL pulse therapy may be risk factors for VAP in the pediatric population.

Eribulin mesylate exerts antitumor effects via CD103.

Eribulin mesylate (ERB) is a synthetic analog of halichondrin B, inhibiting tumor cell growth by disrupting microtubule function. Recently, anticancer drugs have been shown to not only act directly on tumor cells but also to exert antitumor effects by modifying the tumor environment. Although ERB has also been speculated to modify the tumor microenvironment including the immune response to tumors, the precise mechanism remains unclear. In our study, ERB suppressed the tumor growth of MC38 colon cancer in wildtype mice, whereas ERB failed to inhibit the tumor growth in Rag1-deficient mice which lack both B and T cells. Moreover, depletion of either CD4+ or CD8+ T cells abrogated the antitumor effect of ERB, indicating that both CD4+ and CD8+ T cells play an important role in ERB-induced antitumor effects. Furthermore, ERB treatment increased the number of tumor infiltrating lymphocytes (TILs) as well as the expression of activation markers (CD38 and CD69), immune checkpoint molecules (LAG3, TIGIT and Tim3) and cytotoxic molecules (granzyme B and perforin) in TILs. ERB upregulated E-cadherin expression in MC38. CD103 is a ligand of E-cadherin and induces T-cell activation. ERB increased the proportion of CD103+ cells in both CD4+ and CD8+ TILs. The ERB-induced antitumor effect with the increased TIL number and the increased expression of activation markers, inhibitory checkpoint molecules and cytotoxic molecules in TILs was abrogated in CD103-deficient mice. Collectively, these results suggest that ERB exerts antitumor effects by upregulation of E-cadherin expression in tumor cells and subsequent activation of CD103+ TILs.

Blockade of CD122 on memory T cells in the skin suppresses sclerodermatous graft-versus-host disease.

BACKGROUND: Antigen-stimulated naïve T cells differentiate into effector and memory T cells, of which resident memory T (TRM) cells reside permanently in organ tissues. Involvement of TRM cells has been indicated in pathological conditions of various skin diseases. CD122, which is the ß chain subunit of interleukin (IL)- 2 and IL-15 receptors, is expressed on immune cells including TRM cells. OBJECTIVE: To investigate whether CD122 signaling in skin CD8+ TRM cells mediates the development of mucocutaneous graft-versus-host disease (GVHD). METHODS: We used a genetically modified mouse expressing a membrane-bound form of chicken ovalbumin (OVA) under the control of the keratin 14 promoter, which develops GVHD-like erosive mucocutaneous disease resulting in sclerodermatous disease after transfer of OVA-specific T cell-receptor-transgenic CD8+ OT-I cells. Mice with mucocutaneous GVHD were treated with an anti-CD122 blocking antibody. RESULTS: Administration of an anti-CD122 blocking antibody suppresses the development of acute/chronic GVHD-like mucocutaneous disease in our murine model via the reduction of CD122-expressing memory CD8+ T cells, including skin, memory autoaggressive CD8+ T cells. Moreover, blockade of CD122, even after the establishment of acute GVHD, inhibited the development of chronic GVHD-like sclerodermatous disease via the reduction of epidermal and dermal TRM autoaggressive CD8+ T cells. CONCLUSION: Skin memory CD8+ T cells in particular mediate the development of mucocutaneous GVHD, and blockade of CD122 may be an effective treatment strategy, especially for sclerodermatous GVHD.

Immature Platelet Fraction and Its Kinetics in Neonates.

Thrombocytopenia is a common abnormality encountered in the neonatal period, and immature platelet fraction (IPF) may be an informative indicator of thrombopoiesis; however, data on IPF in neonates are scarce. To define reference intervals (RIs) and factors affecting IPF in neonates, we measured the IPF of 533 consecutive neonates. With a multiple regression analysis of 330 newborns with normal platelet counts at birth, premature delivery, neonatal asphyxia, intrauterine infection, chromosomal abnormalities, and respiratory disorders were identified as independent factors for IPF%. The RIs of IPF% and absolute IPF value in neonates were determined to be 1.3% to 5.7% and 3.2 to 14.5×10 9 /L, respectively. On day 14 after birth, IPF% increased to twice the value at birth and thereafter returned to the previous value on day 28. Reticulocyte counts, in contrast, were the lowest at day 14. IPF% was increased in 16 thrombocytopenic patients with various clinical conditions, especially those with immune-mediated thrombocytopenia. IPF in neonates may be evaluated essentially based on the same RIs as in adults, although some precautions must be taken when evaluating IPF in neonates in the first 2 weeks of life. IPF may be useful for evaluating thrombopoiesis and thrombocytopenia in neonates.

Glutathione Depletion and MicroRNA Dysregulation in Multiple System Atrophy: A Review.

Multiple system atrophy (MSA) is a rare neurodegenerative disease characterized by parkinsonism, cerebellar impairment, and autonomic failure. Although the causes of MSA onset and progression remain uncertain, its pathogenesis may involve oxidative stress via the generation of excess reactive oxygen species and/or destruction of the antioxidant system. One of the most powerful antioxidants is glutathione, which plays essential roles as an antioxidant enzyme cofactor, cysteine-storage molecule, major redox buffer, and neuromodulator, in addition to being a key antioxidant in the central nervous system. Glutathione levels are known to be reduced in neurodegenerative diseases. In addition, genes regulating redox states have been shown to be post-transcriptionally modified by microRNA (miRNA), one of the most important types of non-coding RNA. miRNAs have been reported to be dysregulated in several diseases, including MSA. In this review, we focused on the relation between glutathione deficiency, miRNA dysregulation and oxidative stress and their close relation with MSA pathology.

Novel Causative RET Mutation in a Japanese Family with Hirschsprung's Disease: Case Report and Factors Impacting Disease Severity.

RET gene variances confer susceptibility to Hirschsprung's disease (HSCR) with pathogenetic mutations being identified in half of familial cases. This investigation of familial HSCR was aimed to clarify the relationship between genetic mutations and clinical phenotype using next-generation sequencing. A novel c2313C > G(D771E) RET mutation was identified in all three affected family members. The mutation involved the kinase domain, which is believe to impair RET activity and intestinal function. A second RET mutation, c1465G > A(D489N), was found only in the extensive aganglionosis case. We conclude that the novel c2313C > A(D771E) mutation in RET may be pathogenic for HSCR, while the c1465C > G(D489N) mutation may be related to phenotype severity.

Detection of Bacillus cereus as a causative agent of emetic food poisoning by an unconventional culture procedure.

Bacillus cereus is known to cause two types of food poisoning: emetic and diarrhoeal. Both diseases are usually self-limiting; however, severe cases have been reported, presenting with acute liver failure and encephalopathy, including rarely fatal cases of vomiting. Clinical laboratories do not routinely test for B. cereus in patients with gastrointestinal disease. Therefore, B. cereus causing food poisoning goes undetected. We report a successful isolation of emetic B. cereus from a patient with food poisoning who presented with severe vomiting, fulminant hepatic failure, and acute encephalopathy, by a non-conventional method. Initially, stool specimens from the patients were routinely cultured to identify the causative organisms of food poisoning. No foodborne pathogens were detected in this study. In contrast, additional clinical and epidemiological information strongly suggested food poisoning by emetic B. cereus. Consequently, we allowed Drigalski agar medium smeared with patient stool specimens to stand at room temperature (approximately 25 °C) for 9 days. After 9 days, mixed bacteria grown on the medium were inoculated onto mannitol egg yolk polymyxin (MYP) agar plates, a selective medium for B. cereus. Typical colonies of B. cereus developed on MYP agar plates. The isolated B. cereus had a cereulide-producing genetic locus (ces) gene encoding the emetic toxin cereulide. The method used in this case study was unique. This method is easy to apply after obtaining an additional clinical and epidemiological information, and this method will improve the diagnostic rate of severe B. cereus food poisoning. This will contribute to the advancement of therapeutics in the future.

The Role of PD-L1 on Langerhans Cells in the Regulation of Psoriasis.

Langerhans cells (LCs) are skin-resident cells with potent antigen-presenting cell capabilities, which reportedly play some roles in the development of psoriasis, an inflammatory skin disease mediated by IL-17A‒producing cells, T helper 17 cells, and TCR-γδlow T cells. LCs in psoriatic skin lesions but not in normal skin express PD-L1, which binds to PD-1, an immune checkpoint molecule, to negatively regulate immune reactions. The aim of this study is to elucidate the regulatory role of LCs through the PD-1/PD-L1 axis in a murine model of imiquimod-induced psoriasis-like dermatitis. Imiquimod application on wild-type C57BL/6J mice induced PD-L1 expression on LCs both in the ear skin and skin-draining lymph nodes. To further identify the functional role of PD-L1 expressed on LCs, we generated conditional knockout mice lacking PD-L1 expression on LCs (Pd-l1-cKO mice). Pd-l1-cKO mice presented significantly more severe imiquimod-induced psoriasis-like dermatitis than their control littermates. Flow cytometric analysis showed that the frequency of activated IL-17A‒producing γδlow T cells was increased in the ear skin samples, and IL-17A production by CCR6+ migrating γδlow T cells increased in the skin-draining lymph nodes in imiquimod-applied Pd-l1-cKO mice than in control littermates. Collectively, LCs disrupt the exacerbation of psoriasis through PD-L1.

Loricrin and NRF2 Coordinate Cornification.

Cornification involves cytoskeletal cross-linkages in corneocytes (the brick) and the secretion of lipids/adhesion structures to the interstitial space (the mortar). Because the assembly of lipid envelopes precedes corneocyte maturation, loricrin is supposed to be dispensable for the protection against desiccation. Although the phenotypes of Lor knockout (LKO) mice are obscure, the antioxidative response on the KEAP1/NRF2 signaling pathway compensates for the structural defect in utero. In this study, we asked how the compensatory response is evoked after the defects are repaired. To this end, the postnatal phenotypes of LKO mice were analyzed with particular attention to the permeability barrier function primarily maintained by the mortar. Ultrastructural analysis revealed substantially thinner cornified cell envelopes and increased numbers of lamellar granules in LKO mice. Superficial epidermal damages triggered the adaptive repairing responses that evoke the NRF2-dependent upregulation of genes associated with lamellar granule secretion in LKO mice. We also found that corneodesmosomes are less degraded in LKO mice. The observation suggests that loricrin and NRF2 are important effectors of cornification, in which proteins need to be secreted, cross-linked, and degraded in a coordinated manner.

Early Phase Increase in Serum TIMP-1 in Patients with Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion.

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most frequent subtype of acute encephalopathy syndrome among Japanese children. Exanthem subitum is the most common causative infectious disease of AESD. We herein retrospectively analyzed serum and cerebrospinal fluid (CSF) concentrations of matrix metalloproteinase-9 (MMP-9), tissue inhibitor matrix metalloproteinase-1 (TIMP-1), and seven cytokines in patients with AESD or prolonged febrile seizure (FS) to assess the pathophysiology of AESD and detect biomarkers for diagnosing AESD in the early phase. METHODS: Serum and CSF samples were obtained from 17 patients with AESD (1st seizure phase group, n = 7; 2nd seizure phase group, n = 10) and 8 with FS. The concentrations of MMP-9, TIMP-1, and seven cytokines were measured by enzyme-linked immunosorbent assays or cytometric bead arrays. RESULTS: Serum concentrations of TIMP-1 were significantly higher in the 1st seizure phase group than in the 2nd seizure phase group. No significant differences were observed in serum concentrations of MMP-9 or the MMP-9/TIMP-1 ratio. CONCLUSIONS: The MMP-9-independent increase in circulating TIMP-1 concentrations observed in the present study may be associated with the pathophysiology of AESD in the 1st seizure phase.

Reliability of antinuclear matrix protein 2 antibody assays in idiopathic inflammatory myopathies is dependent on target protein properties.

A line blotting assay (LB) is currently used to detect myositis-specific autoantibodies (MSAs) in patients with idiopathic inflammatory myopathies (IIMs), because of its simplicity; however, the sensitivity and specificity of this assay is low. The aim of this study is to evaluate the accuracy of the commercial LB in detection of antinuclear matrix protein 2 (NXP2) antibody. Seventy-seven serum samples from patients with IIMs, in which anti-NXP2 antibodies were detected through immunoprecipitation and western blotting (IP-WB) using K562 cell lysate, were enrolled. All samples were assessed by LB and IP-WB using recombinant human NXP2 whole protein (rNXP2) produced by insect cells, and the positive rates of each assay were compared. Thirty-two samples (41.6%) showed false-negativity by LB, which includes 11 samples with negative results by IP-WB using rNXP2. Relative intensities of IP-WB using cell lysate were significantly higher in the samples with positive results by both LB and IP-WB using rNXP2, compared to samples with positive by IP-WB using rNXP2 but negative by LB. Three of 11 samples with negative results by both LB and IP-WB using rNXP2 revealed high antibody titers. Further, differences in post-transcriptional SUMOylation were observed between recombinant and natural NXP2 proteins. In conclusion, the LB showed low sensitivity for detection of anti-NXP2 antibody, an effect exacerbated at low titers of anti-NXP2 antibodies. Moreover, there appears to be differences in the reactivities of antibodies to recombinant and natural NXP2 proteins with different post-transcriptional modifications.