Ameliorating Fibrosis in Murine and Human Tissues with END55, an Endostatin-Derived Fusion Protein Made in Plants.

Organ fibrosis, particularly of the lungs, causes significant morbidity and mortality. Effective treatments are needed to reduce the health burden. A fragment of the carboxyl-terminal end of collagen XVIII/endostatin reduces skin and lung fibrosis. This fragment was modified to facilitate its production in plants, which resulted in the recombinant fusion protein, END55. We found that expression of END55 had significant anti-fibrotic effects on the treatment and prevention of skin and lung fibrosis in a bleomycin mouse model. We validated these effects in a second mouse model of pulmonary fibrosis involving inducible, lung-targeted expression of transforming growth factor ß1. END55 also exerted anti-fibrotic effects in human lung and skin tissues maintained in organ culture in which fibrosis was experimentally induced. The anti-fibrotic effect of END55 was mediated by a decrease in the expression of extracellular matrix genes and an increase in the levels of matrix-degrading enzymes. Finally, END55 reduced fibrosis in the lungs of patients with systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF) who underwent lung transplantation due to the severity of their lung disease, displaying efficacy in human tissues directly relevant to human disease. These findings demonstrate that END55 is an effective anti-fibrotic therapy in different organs.

Effectiveness of a doctor dispatch system activated by an advanced automatic collision notification from a single-vehicle accident: A case report.

A 79-year-old woman collided with a cliff in a passenger automobile. The fire department acknowledged an automated collision notification from the D-Call Net (DCN) at 1 min after the accident and called for doctors by helicopter ("Doctor-Heli" [DH] in Japan) 9 min after the injury. The DH reached the victim 28 min after the injury, and examinations revealed pain in the right side of her chest, tachypnea, and a weak radial artery pulse (indicating shock). The DH arrived at the hospital 49 min after the injury. A thoracic drainage was performed for right-sided tension pneumothorax. She recovered from the shock, but was diagnosed with flail chest and placed on a respirator. She was extubated on postoperative day 6 and transferred to a rehabilitation hospital on postoperative day 57. Due to the DCN, the patient received treatment 15 min earlier than the time taken by the conventional system. Emergency response task forces must develop strategies for connecting DCN warnings to a rapid medical response.

Use of a Simulation Model to Investigate the Mechanisms of Sports-related Head Injuries.

A simulation model was developed to better understand the mechanisms of brain injuries in sports. A three-dimensional model comprising approximately 1.22 million elements was constructed from cranial computed tomography images of adult male volunteers by the voxel method. To simulate contact sports that permit actions such as tackling, a sinusoidal wave with duration of 10 ms and maximum acceleration of 2000 m/s2 was applied to the lowest point of the model to apply rotational acceleration to the head from different directions. The von Mises stress was then observed at five points in the coronal plane of the brain: cingulate gyrus (CG), corpus callosum (CC), brain stem (BS), lateral temporal lobe (LT), and medial temporal lobe (MT). LS-DYNA universal finite element analysis software with explicit time integration was used for the analysis. Concentrations of stress started to appear in the CC and BS at 10 ms post-impact, after which they also became evident in the CG and MT. The maximum changes in stress at each location occurred 10-15 ms post-impact. The von Mises stress was 9-14 kPa in the CG, 8-24 kPa in the CC, 12-24 kPa in the BS, 7-12 kPa in the LT, and 12-18 kPa in the MT. The highest stress in every part of the brain occurred after lateral impact, followed by oblique impact and sagittal impact. Such simulations may help elucidate the mechanisms of brain injuries in sports and help develop measures to prevent chronic traumatic encephalopathy.

E4 engages uPAR and enolase-1 and activates urokinase to exert antifibrotic effects.

Fibroproliferative disorders such as systemic sclerosis (SSc) have no effective therapies and result in significant morbidity and mortality. We recently demonstrated that the C-terminal domain of endostatin, known as E4, prevented and reversed both dermal and pulmonary fibrosis. Our goal was to identify the mechanism by which E4 abrogates fibrosis and its cell surface binding partner(s). Our findings show that E4 activated the urokinase pathway and increased the urokinase plasminogen activator (uPA) to type 1 plasminogen activator inhibitor (PAI-1) ratio. In addition, E4 substantially increased MMP-1 and MMP-3 expression and activity. In vivo, E4 reversed bleomycin induction of PAI-1 and increased uPA activity. In patients with SSc, the uPA/PAI-1 ratio was decreased in both lung tissues and pulmonary fibroblasts compared with normal donors. Proteins bound to biotinylated-E4 were identified as enolase-1 (ENO) and uPA receptor (uPAR). The antifibrotic effects of E4 required uPAR. Further, ENO mediated the fibrotic effects of TGF-ß1 and exerted TGF-ß1-independent fibrotic effects. Our findings suggest that the antifibrotic effect of E4 is mediated, in part, by regulation of the urokinase pathway and induction of MMP-1 and MMP-3 levels and activity in a uPAR-dependent manner, thus promoting extracellular matrix degradation. Further, our findings identify a moonlighting function for the glycolytic enzyme ENO in fibrosis.

Lysyl oxidase directly contributes to extracellular matrix production and fibrosis in systemic sclerosis.

Pulmonary fibrosis is one of the important causes of morbidity and mortality in fibroproliferative disorders such as systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF). Lysyl oxidase (LOX) is a copper-dependent amine oxidase whose primary function is the covalent crosslinking of collagens in the extracellular matrix (ECM). We investigated the role of LOX in the pathophysiology of SSc. LOX mRNA and protein levels were increased in lung fibroblasts of SSc patients compared with healthy controls and IPF patients. In vivo, bleomycin induced LOX mRNA expression in lung tissues, and LOX activity increased in the circulation of mice with pulmonary fibrosis, suggesting that circulating LOX parallels levels in lung tissues. Circulating levels of LOX were reduced upon amelioration of fibrosis with an antifibrotic peptide. LOX induced ECM production at the transcriptional level in lung fibroblasts, human lungs, and human skin maintained in organ culture. In vivo, LOX synergistically exacerbated fibrosis in bleomycin-treated mice. Further, LOX increased the production of interleukin (IL)-6, and the increase was mediated by LOX-induced c-Fos expression, the nuclear localization of c-Fos, and its engagement with the IL-6 promoter region. Our findings demonstrate that LOX expression and activity correlate with fibrosis in vitro, ex vivo, and in vivo. LOX induced ECM production via upregulation of IL-6 and nuclear localization of c-Fos. Thus, LOX has a direct pathogenic role in SSc-associated fibrosis that is independent of its crosslinking function. Our findings also suggest that measuring circulating LOX levels and activity can be used for monitoring response to antifibrotic therapy.

A unique thymus-derived regulatory T cell subset associated with systemic lupus erythematosus.

BACKGROUND: Foxp3 is a marker for regulatory T cells (Treg cells), but recent studies have shown the plasticity and heterogeneity of CD4+Foxp3+ T cells. This study aimed to examine the phenotype and function of circulating CD4+Foxp3+ T cells in patients with systemic lupus erythematosus (SLE). METHODS: We enrolled 47 patients with SLE, 31 with organ-specific autoimmune diseases (15 with multiple sclerosis and 16 with primary immune thrombocytopenia), and 19 healthy subjects. Peripheral blood mononuclear cells were used to evaluate the proportion and phenotype of CD4+Foxp3+ cells using multicolor flow cytometry, the status of the Treg-specific demethylated region (TSDR) of the foxp3 gene by methylation-specific polymerase chain reaction, and the immunoregulatory function of CD4+CD25+ cells by allogeneic mixed lymphocyte reaction. Immunohistochemistry of renal biopsy specimens obtained from 6 patients with lupus nephritis and 5 with IgA nephropathy was conducted to detect IL-17A-expressing CD4+Foxp3+ cells. RESULTS: CD4+Foxp3+ T cells were increased in SLE patients compared with organ-specific autoimmune disease controls or healthy controls. Circulating CD4+Foxp3+ T cells were correlated with the disease activity of SLE. The increased CD4+Foxp3+ T cells in active SLE patients were mainly derived from thymus-derived Treg (tTreg) cells, as determined by a demethylated TSDR status, and represented a unique phenotype, upregulated expression of CD49d, CD161, and IL-17A, with immunosuppressive ability comparable to that of healthy controls. Finally, CD4+Foxp3+IL-17A+ cells were infiltrated into the renal biopsy specimens of patients with active lupus nephritis. CONCLUSIONS: A unique tTreg subset with dichotomic immunoregulatory and T helper 17 phenotypes is increased in the circulation of SLE patients and may be involved in the pathogenic process of SLE.

A System That Uses Advanced Automatic Collision Notification Technology to Dispatch Doctors to Traffic Accidents by Helicopter: The First 4 Cases.

INTRODUCTION: To increase survival rates of patients with severe trauma from road traffic accidents, Japan launched the D-Call Net (DCN) system, which utilizes advanced automatic collision notification technology to dispatch doctors by helicopter. The DCN system began in November 2015 and, as of October 2019, has dispatched doctors 4 times. CASES: Case 1-Canceled because trauma was mild. Case 2-Doctor made contact with 2 patients with moderate trauma 29 minutes earlier than would have occurred conventionally. This was the first case in the world to use automotive engineering data to dispatch a doctor to a patient. Case 3-An accident involving 3 severely injured patients activated DCN, enabling doctor-patient contact 20 minutes earlier than would have been possible conventionally. Case 4-DCN was ineffective. DISCUSSION: According to 2008 data from Chiba Prefecture, in accidents where victims sustain severe trauma, the interval from accident occurrence to hospital arrival was 67 minutes, even when doctors were dispatched by air ambulance (Doctor-Heli [DH]). Use of accident information for faster doctor dispatch effectively improved survival rates. An algorithm was developed to use accident information to assess trauma severity (severity probability). DCN dispatches doctors by using data, including information on accident site and severity probability, which are sent to smartphones of doctors, thereby reducing the interval from accident to DH request by approximately 17 minutes. DCN is the first system in the world to use automotive engineering information for faster doctor dispatch to traffic accident sites. The system is crucial for improving survival rates and mitigating the aftereffects of traffic accidents.

Thoracoabdominal Compression Model of Traumatic Asphyxia to Identify Mechanisms of Respiratory Failure in Fatal Crowd Accidents.

BACKGROUND: Traumatic asphyxia is a major cause of death in fatal crowd disasters, but the relationships between compression site, load magnitude, load time, and medical outcomes are unclear. This study estimated thoracoabdominal compression conditions (load magnitude, load time) that could result in respiratory failure in adults. METHODS: Eight load patterns-A (chest load: 0 kg, abdominal load: 10 kg), B (0, 20), C (10, 0), D (10, 10), E (10, 20), F (20, 0), G (20, 10), and H (20, 20)-were applied to 14 healthy women. Blood pressure, heart rate, respiratory rate, SpO2, tidal volume, vital capacity, respiratory phase, and modified Borg dyspnea score were measured over time. Breathing Intolerance Index (BITI) was also calculated. RESULTS: Vital capacity decreased in patterns C, D, E, F, G, and H. BITI reached the critical range of ≥0.15 (at which respiratory failure occurs after about 45 min) after 14 min in pattern G and 2 min in pattern H. A vital capacity ≤1.85 L and a modified Borg scale score ≥8.3 corresponded to a BITI of ≥0.15 and were regarded as equivalent to reaching the critical range. Furthermore, change in chest load was positively correlated with BITI when abdominal load remained constant. CONCLUSIONS: In women, respiratory failure can occur within 1 h from respiratory muscle fatigue, even when total thoracoabdominal load is only about 60% of body weight. A vital capacity ≤1.85 L and modified Borg scale score ≥8.3 can be regarded as indices for predicting respiratory failure.

Insulin-like growth factor binding protein-4 exerts antifibrotic activity by reducing levels of connective tissue growth factor and the C-X-C chemokine receptor 4.

The Insulin-like growth factor (IGF) system plays an important role in variety cellular biological functions; we previously reported levels of IGF binding proteins (IGFBP) -3 and -5 are increased in dermal and pulmonary fibrosis associated with the prototypic fibrosing disease systemic sclerosis (SSc), induce extracellular matrix (ECM) production, and promote fibrosis. We sought to examine the effects of another member of the family, IGFBP-4, on ECM production and fibrosis using cell-based, ex vivo organ culture and in vivo mouse lung fibrosis models. IGFBP-4 mRNA levels were significantly decreased in pulmonary fibroblasts of patients with SSc. ECM components were significantly reduced by endogenous and exogenous IGFBP-4. IGFBP-4 also blocked TGFß-induced ECM production, and inhibited ECM production ex vivo in human lung and skin in organ culture. In vivo, IGFBP-4 reduced bleomycin-induced collagen production and histologic evidence of fibrosis. Silencing IGFBP-4 expression to mimic levels observed in SSc lung fibroblasts resulted in increased ECM production. IGFBP-4 reduced mRNA and protein levels of the chemokine receptor CXCR4 and the pro-fibrotic factor CTGF. Further, CTGF silencing potentiated the anti-fibrotic effects of IGFBP-4. Reduced IGFBP-4 levels in SSc lung fibroblasts may contribute to the fibrotic phenotype via loss of IGFBP-4 anti-fibrotic activity.

A pedestrian serious injury risk prediction method based on posted speed limit.

The purpose of this study was to develop a serious injury risk prediction algorithm for pedestrians, using data from the South Australian Traffic Accident Reporting System. Two algorithms were developed to estimate serious injury risk, using a logistic regression analysis of 6,868 vehicle-pedestrian crashes extracted from TARS data. In this study, an optimal model based on the best combination of risk factors according to the Akaike information criterion (AIC) was developed. Additionally, a secondary GPS model using only crash site characteristics that can be derived from GPS coordinates from the crash scene was also developed. The optimal model is based on site and environmental conditions that could be derived from GPS data (posted speed limit, distance from crash site, natural lighting conditions, road geometry, road horizontal alignment and road vertical alignment) as well as pedestrian age/gender, driver age/gender and vehicle model year. The second model only included features that could be derived from GPS data. The optimal model was reasonable in accuracy and gave an under-triage rate of 10% when the injury threshold was set to 15%, with a corresponding over-triage rate of around 60%. The GPS model, despite not being as accurate as the optimal model may be adequate in the absence of all the risk factors required for the optimal model, requiring an injury threshold of 20% to give an under-triage rate of 10%, with the corresponding over-triage rate being around 70%. Both models can potentially be used for serious injury risk prediction (SIRP) for pedestrians involved in a collision with a vehicle.

Optimization of a murine and human tissue model to recapitulate dermal and pulmonary features of systemic sclerosis.

The murine bleomycin (BLM)-induced fibrosis model is the most widely used in systemic sclerosis (SSc) studies. It has been reported that systemic delivery of BLM via continuous diffusion from subcutaneously implanted osmotic minipumps can cause fibrosis of the skin, lungs, and other internal organs. However, the mouse strain, dosage of BLM, administration period, and additional important features differ from one report to the next. In this study, by employing the pump model in C57BL/6J mice, we show a dose-dependent increase in lung fibrosis by day 28 and a transient increase in dermal thickness. Dermal thickness and the level of collagen in skin treated with high-dose BLM was significantly higher than in skin treated with low dose BLM or vehicle. A reduction in the thickness of the adipose layer was noted in both high and low dose groups at earlier time points suggesting that the loss of the fat layer precedes the onset of fibrosis. High-dose BLM also induced dermal fibrosis and increased expression of fibrosis-associated genes ex vivo in human skin, thus confirming and extending the in vivo findings, and demonstrating that a human organ culture model can be used to assess the effect of BLM on skin. In summary, our findings suggest that the BLM pump model is an attractive model to analyze the underlying mechanisms of fibrosis and test the efficacy of potential therapies. However, the choice of mouse strain, duration of BLM administration and dose must be carefully considered when using this model.

Serious injury prediction algorithm based on large-scale data and under-triage control.

The present study was undertaken to construct an algorithm for an advanced automatic collision notification system based on national traffic accident data compiled by Japanese police. While US research into the development of a serious-injury prediction algorithm is based on a logistic regression algorithm using the National Automotive Sampling System/Crashworthiness Data System, the present injury prediction algorithm was based on comprehensive police data covering all accidents that occurred across Japan. The particular focus of this research is to improve the rescue of injured vehicle occupants in traffic accidents, and the present algorithm assumes the use of an onboard event data recorder data from which risk factors such as pseudo delta-V, vehicle impact location, seatbelt wearing or non-wearing, involvement in a single impact or multiple impact crash and the occupant's age can be derived. As a result, a simple and handy algorithm suited for onboard vehicle installation was constructed from a sample of half of the available police data. The other half of the police data was applied to the validation testing of this new algorithm using receiver operating characteristic analysis. An additional validation was conducted using in-depth investigation of accident injuries in collaboration with prospective host emergency care institutes. The validated algorithm, named the TOYOTA-Nihon University algorithm, proved to be as useful as the US URGENCY and other existing algorithms. Furthermore, an under-triage control analysis found that the present algorithm could achieve an under-triage rate of less than 10% by setting a threshold of 8.3%.

Mouse immune thrombocytopenia is associated with Th1 bias and expression of activating Fcγ receptors.

Immune thrombocytopenia (ITP) is an autoimmune disease mediated by anti-platelet autoantibodies. We recently established a mouse ITP model exhibiting regulatory T-cell (Treg) deficiency, although only one-third of the Treg-deficient mice developed ITP. To clarify mechanisms involved in the emergence of platelet-specific autoimmunity in this model, we examined the T helper (Th)-cell balance and macrophage Fcγ receptor (FcγR) expression profiles in Treg-deficient mice with and without ITP. Splenocytes from both populations of Treg-deficient mice and control BALB/c mice were subjected to flow cytometry-based analyses to evaluate Th cell subset proportions and the expression of activating and inhibitory FcγRs on macrophages. In addition, IgG subclass distribution of anti-platelet autoantibodies in splenocyte culture supernatants was determined by flow cytometry using IgG subclass-specific antibodies. Treg-deficient ITP mice exhibited a significantly higher proportion of Th1 cells than either Treg-deficient non-ITP or control mice. The predominant anti-platelet autoantibody subclasses in the ITP mice were Th1-associated IgG2a and IgG2b. Furthermore, the FcγRI/FcγRIIB expression ratio in splenic macrophages was higher in the Treg-deficient ITP than in the Treg-deficient non-ITP and control mice. In summary, Th1 polarization and macrophages' activating FcγR expression profile are associated with the development of ITP in Treg-deficient mice.

An endostatin-derived peptide orally exerts anti-fibrotic activity in a murine pulmonary fibrosis model.

OBJECTIVE: Pulmonary fibrosis causes high morbidity and mortality in affected individuals. Recently, we showed that parenteral or intratracheal administration of a peptide derived from endostatin, called E4, prevents and ameliorates fibrosis using different models of dermal and pulmonary disease. No marketed orally delivered peptide drugs are currently available for progressive pulmonary fibrosis; however oral delivery of drugs is the preferred route for treating most chronic diseases. Thus, we investigated whether oral administration of E4 peptide exerted anti-fibrotic activity in a murine pulmonary fibrosis model. METHODS: Bleomycin (1.2mU/g body weight) was intratracheally administrated to male 6-8-week-old C57BL/6J mice. E4 peptide (20, 10, 5, and 1 µg/mouse) or scrambled control peptide (20 µg/mouse) was orally administered on the same day as bleomycin. In some experiments, E4 peptide (10 and 5 µg/mouse) was orally administered three times on days 0, 3, and 6 post-bleomycin treatment. Lungs were harvested on day 21 for histological analysis and hydroxyproline assay. RESULTS: Histological analysis and hydroxyproline assay revealed that bleomycin successfully induced pulmonary fibrosis, and that 20 µg of oral E4 peptide ameliorated the fibrosis. The lower doses of E4 peptide (10, 5, and 1 µg) were insufficient to exert anti-fibrotic activity when given as a single dose. Multiple doses of E4 peptide efficiently exerted anti-fibrotic activity even at lower doses. CONCLUSION: E4 peptide shows oral bioavailability and exerts anti-fibrotic activity in a bleomycin-induced pulmonary fibrosis model. We suggest that E4 peptide is a novel oral drug for fibroproliferative disorders.

IGFBP-5 Promotes Fibrosis Independently of Its Translocation to the Nucleus and Its Interaction with Nucleolin and IGF.

BACKGROUND: Insulin-like growth factor binding protein (IGFBP)-5 levels are increased in systemic sclerosis (SSc) skin and lung. We previously reported that IGFBP-5 is a pro-fibrotic factor that induces extracellular matrix (ECM) production and deposition. Since IGFBP-5 contains a nuclear localization signal (NLS) that facilitates its nuclear translocation, we sought to examine the role of nuclear translocation on the fibrotic activity of IGFBP-5 and identify IGFBP-5 binding partners relevant for its nuclear compartmentalization. METHODS: We generated functional wild type IGFBP-5 and IGFBP-5 with a mutated NLS or a mutated IGF binding site. Abrogation of nuclear translocation in the NLS mutant was confirmed using immunofluorescence and immunoblotting of nuclear and cytoplasmic cellular extracts. Abrogation of IGF binding was confirmed using western ligand blot. The fibrotic activity of wild type and mutant IGFBP-5 was examined in vitro in primary human fibroblasts and ex vivo in human skin. We identified IGFBP-5 binding partners using immunoprecipitation and mass spectrometry. We examined the effect of nucleolin on IGFBP-5 localization and function via sequence-specific silencing in primary human fibroblasts. RESULTS: Our results show that IGFBP-5-induced ECM production in vitro in primary human fibroblasts is independent of its nuclear translocation. The NLS-mutant also induced fibrosis ex vivo in human skin, thus confirming and extending the in vitro findings. Similar findings were obtained with the IGF-binding mutant. Nucleolin, a nucleolar protein that can serve as a nuclear receptor, was identified as an IGFBP-5 binding partner. Silencing nucleolin reduced IGFBP-5 translocation to the nucleus but did not block the ability of IGFBP-5 to induce ECM production and a fibrotic phenotype. CONCLUSIONS: IGFBP-5 transport to the nucleus requires an intact NLS and nucleolin. However, nuclear translocation is not necessary for IGFBP-5 fibrotic activity; neither is IGF binding. Our data provide further insights into the role of cellular compartmentalization in IGFBP-5-induced fibrosis.

Induction of immune tolerance to platelet antigen by short-term thrombopoietin treatment in a mouse model of immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune disorder caused by IgG anti-platelet autoantibodies. Thrombopoietin (TPO) receptor agonists are highly effective in inducing the recovery of platelet counts in ITP patients. Although these agents are thought to promote platelet production without affecting the autoimmune pathogenesis of the disease, a small subset of ITP patients exhibits sustained platelet recovery after treatment termination. To investigate mechanisms involved in this sustained recovery, we evaluated the effects of short-term TPO treatment using a mouse ITP model generated by Foxp3(+) T regulatory cell (Treg) depletion. After treatment, platelet recovery was sustained, along with complete suppression of both anti-platelet autoantibody production and T-cell responses to platelet autoantigens. TPO treatment also promoted the peripheral induction of Foxp3(+) Tregs in conjunction with elevated circulating TGF-ß levels. In summary, thrombopoietic agents are capable of inducing immune tolerance to platelet autoantigens, thereby suppressing the autoimmune pathogenesis of ITP.

CD4+CD25+Foxp3+ regulatory T cells in the pathophysiology of immune thrombocytopenia.

Regulatory T cells characterized by CD4, CD25, and transcription factor forkhead box P3, called Tregs, are a subpopulation of CD4(+) T cells specialized for immune suppression. Tregs contribute to maintenance of peripheral immune tolerance, and their defects are thought to play a role in the pathogenesis of various autoimmune diseases. Immune thrombocytopenia (ITP) is an autoimmune disease characterized by increased platelet destruction and reduced platelet production, resulting in decreased platelet count. Recently, a series of studies in adults and children with ITP have found that the frequency of Tregs is reduced in circulation, bone marrow, and spleen, and Treg function is impaired. Treg dysregulation is improved after platelet count is recovered by treatment with dexamethasone, rituximab, or thrombopoietin receptor agonists. In addition, a critical role of Tregs in preventing the anti-platelet autoimmune response has been demonstrated in mice deficient in functional Tregs. Thrombocytopenia observed in Treg-deficient mice is mediated through production of IgG anti-platelet autoantibodies, which is analogous to human ITP. Further studies evaluating mechanisms of Treg dysregulation in ITP patients are necessary to elucidate the pathogenesis of ITP and develop novel therapeutic strategies that suppress anti-platelet autoimmune response.

Clinical and immunological predictors of prognosis for Japanese patients with thymoma-associated myasthenia gravis.

There are no immunological markers to predict the prognosis of thymoma-associated myasthenia gravis (MG). Clinical and immunological factors associated with thymoma recurrence or MG relapse were examined by logistic analyses in 56 Japanese patients with thymoma-associated MG. Patients with anti-Kv1.4 antibodies showed higher frequencies of thymoma recurrence and MG relapse compared to those without. Anti-Kv1.4 antibody, Masaoka stage 4, World Health Organization type B3, and adjuvant radiotherapy were associated with thymoma recurrence. Multivariate analyses showed that anti-Kv1.4 antibody was the only independent factor associated with MG relapse. Anti-Kv1.4 antibody is a useful predictor of the prognosis of thymoma-associated MG.

PLD4 as a novel susceptibility gene for systemic sclerosis in a Japanese population.

OBJECTIVE: Systemic sclerosis (SSc) is an autoimmune disease for which multiple susceptibility genes have been reported. Genome-wide association studies have shown that large numbers of susceptibility genes are shared among autoimmune diseases. Recently, our group identified 9 novel susceptibility genes associated with rheumatoid arthritis (RA) in a Japanese population. The aim of this study was to elucidate whether the 18 genes that displayed associations or suggestive associations for RA in our previous study are associated with SSc in Japanese. METHODS: We performed an association study that included 415 patients with SSc and 16,891 control subjects, followed by a replication study that included 315 patients and 21,054 control subjects. The 18 markers reported to display association with RA were analyzed for their associations with SSc in the first study, and 5 markers were further analyzed in the replication study. The inverse variance method was used to evaluate the associations of these markers with SSc in a combined study. RESULTS: In the phospholipase D4 gene (PLD4), rs2841277 displayed a significant association with SSc in Japanese patients (P = 0.00017). We observed that rs2841280 in exon 2 of PLD4 was in strong linkage disequilibrium with rs2841277 and introduced an amino acid alteration. We also observed associations between SSc and rs6932056 in TNFAIP3 and rs2280381 in IRF8 (P = 0.0000095 and P = 0.0030, respectively), both of which displayed associations with SSc in a European population. CONCLUSION: We determined that PLD4 is a novel susceptibility gene for SSc in Japanese, thus confirming the involvement of PLD4 in autoimmunity. Associations between SSc and TNFAIP3 or IRF8 were also detected in our Japanese population. SSc and RA appear to share relatively large proportions of their genetic backgrounds.