Genome-wide association study reveals an association between the HLA-DPB1∗02:01:02 allele and wheat-dependent exercise-induced anaphylaxis.

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a life-threatening food allergy triggered by wheat in combination with the second factor such as exercise. The identification of potential genetic risk factors for this allergy might help high-risk individuals before consuming wheat-containing food. We aimed to identify genetic variants associated with WDEIA. A genome-wide association study was conducted in a discovery set of 77 individuals with WDEIA and 924 control subjects via three genetic models. The associations were confirmed in a replication set of 91 affected individuals and 435 control individuals. Summary statistics from the combined set were analyzed by meta-analysis with a random-effect model. In the discovery set, a locus on chromosome 6, rs9277630, was associated with WDEIA in the dominant model (OR = 3.95 [95% CI, 2.31-6.73], p = 7.87 × 10-8). The HLA-DPB1∗02:01:02 allele displayed the most significant association with WDEIA (OR = 4.51 [95% CI, 2.66-7.63], p = 2.28 × 10-9), as determined via HLA imputation following targeted sequencing. The association of the allele with WDEIA was confirmed in replication samples (OR = 3.82 [95% CI, 2.33-6.26], p = 3.03 × 10-8). A meta-analysis performed in the combined set revealed that the HLA-DPB1∗02:01:02 allele was significantly associated with an increased risk of WDEIA (OR = 4.13 [95% CI, 2.89-5.93], p = 1.06 × 10-14). Individuals carrying the HLA-DPB1∗02:01:02 allele have a significantly increased risk of WDEIA. Further validation of these findings in independent multiethnic cohorts is needed.

Semaphorins guide the entry of dendritic cells into the lymphatics by activating myosin II.

The recirculation of leukocytes is essential for proper immune responses. However, the molecular mechanisms that regulate the entry of leukocytes into the lymphatics remain unclear. Here we show that plexin-A1, a principal receptor component for class III and class VI semaphorins, was crucially involved in the entry of dendritic cells (DCs) into the lymphatics. Additionally, we show that the semaphorin Sema3A, but not Sema6C or Sema6D, was required for DC transmigration and that Sema3A produced by the lymphatics promoted actomyosin contraction at the trailing edge of migrating DCs. Our findings not only demonstrate that semaphorin signals are involved in DC trafficking but also identify a previously unknown mechanism that induces actomyosin contraction as these cells pass through narrow gaps.

Endogenous intracellular cathelicidin enhances TLR9 activation in dendritic cells and macrophages.

Cathelicidins are a gene family best known for their antimicrobial action, but the diverse mature peptides they encode also have other host defense functions. The human cathelicidin peptide LL-37 enhances recognition of nucleic acids, an action whose significance is seen in human diseases such as psoriasis where it is associated with increased type 1 IFN production. This function has been attributed to the extracellular action of the peptide to facilitate uptake of nucleic acids. In this study, we demonstrate that the murine mature cathelicidin peptide (CRAMP), encoded by the mouse gene (Camp), is functionally distinct from the human mature peptide (LL-37), as it does not facilitate CpG entry. However, mouse cathelicidin does influence recognition of CpG as bone marrow-derived dendritic cells from Camp(-/-) mice have impaired CpG responses and Camp(-/-) mice had impaired response to CpG given i.v. or s.c. We show that cathelicidin concentrates in Lamp1 positive compartments, is colocalized with CpG in the endolysosome, can be immunoprecipitated with TLR9, and binds to CpG intracellulary. Collectively, these results indicate that the functions of cathelicidin in control of TLR9 activation may include both intracellular and extracellular effects.

Autoimmune bullous disease and Hashimoto's disease complicated by acquired hemophilia A.

A 67-year-old man was admitted with a 1-month history of spontaneous hematoma in his right back and severe anemia. He had suffered from rashes with blisters involving both legs for 10 years, which had shown worsening and extended to his entire body concurrently with the hematoma. APTT was markedly prolonged to 119 seconds, and Factor VIII:C and FVIII inhibitor levels were less than 1% and 153.1 BU/ml, respectively, confirming the diagnosis of acquired hemophilia A (AHA). Skin biopsy revealed his rashes to be caused by autoimmune bullous disease (ABD), and laboratory and physical findings showed that he also had autoimmune hypothyroidism (Hashimoto's disease). Recombinant FVIIa was effective for management of his bleeding; in addition, FVIII inhibitor reduction and FVIII:C recovery, in parallel with improvement of the skin lesions, were achieved by administering prednisolone and cyclophosphamide. To our knowledge, this is the first report of AHA associated with ABD and Hashimoto's disease.

Elevation of Sema4A implicates Th cell skewing and the efficacy of IFN-ß therapy in multiple sclerosis.

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the CNS and a leading cause of lasting neurologic disabilities in young adults. Although the precise mechanism remains incompletely understood, Ag presentation and subsequent myelin-reactive CD4(+) T cell activation/differentiation are essential for the pathogenesis of MS. Although semaphorins were initially identified as axon guidance cues during neural development, several semaphorins are crucially involved in various phases of immune responses. Sema4A is one of the membrane-type class IV semaphorins, which we originally identified from the cDNA library of dendritic cell (DC). Sema4A plays critical roles in T cell activation and Th1 differentiation during the course of experimental autoimmune encephalomyelitis, an animal model of MS; however, its pathological involvement in human MS has not been determined. In this study, we report that Sema4A is increased in the sera of patients with MS. The expression of Sema4A is increased on DCs in MS patients and shed from these cells in a metalloproteinase-dependent manner. DC-derived Sema4A is not only critical for Th1 but also for Th17 cell differentiation, and MS patients with high Sema4A levels exhibit Th17 skewing. Furthermore, patients with high Sema4A levels have more severe disabilities and are unresponsive to IFN-ß treatment. Taken together, our results suggest that Sema4A is involved in the pathogenesis of MS by promoting Th17 skewing.

Identification of semaphorin 4B as a negative regulator of basophil-mediated immune responses.

Basophils are strong mediators of Th2 responses during helminthic infections. Recently, basophils were shown to function as APCs and promote both Th2 skewing and humoral memory responses. However, the mechanisms that regulate basophils are still unclear. In this article, we show that a class IV semaphorin, Sema4B, negatively regulates basophil functions through T cell-basophil contacts. In a screen to identify semaphorins that function in the immune system, we determined that Sema4B is expressed in T and B cells. Interestingly, Sema4B(-/-) mice had considerably increased serum IgE levels despite normal lymphocyte and dendritic cell functions. Recombinant Sema4B significantly inhibited IL-4 and IL-6 production from basophils in response to various stimuli, including IL-3, papain, and FcεRI cross-linking. In addition, T cell-derived Sema4B, which accumulated at contact sites between basophils and CD4(+) T cells, suppressed basophil-mediated Th2 skewing, suggesting that Sema4B regulates basophil responses through cognate cell-cell contacts. Furthermore, Sema4B(-/-) mice had enhanced basophil-mediated memory IgE production, which was abolished by treating with an anti-FcεRIα Ab. Collectively, these results indicate that Sema4B negatively regulates basophil-mediated Th2 and humoral memory responses.

Gap junction-mediated contraction of myoepithelial cells induces the peristaltic transport of sweat in human eccrine glands.

Eccrine sweat glands play an essential role in regulating body temperature. Sweat is produced in the coiled secretory portion of the gland, which is surrounded by obliquely aligned myoepithelial cells; the sweat is then peristaltically transported to the skin surface. Myoepithelial cells are contractile and have been implicated in sweat transport, but how myoepithelial cells contract and transport sweat remains unexplored. Here, we perform ex vivo live imaging of an isolated human eccrine gland and demonstrate that cholinergic stimulation induces dynamic contractile motion of the coiled secretory duct that is driven by gap junction-mediated contraction of myoepithelial cells. The contraction of the secretory duct occurs segmentally, and it is most prominent in the region surrounded by nerve fibers, followed by distension-contraction sequences of the excretory duct. Overall, our ex vivo live imaging approach provides evidence of the contractile function of myoepithelial cells in peristaltic sweat secretion from human eccrine glands.

Roles of Sema4D-plexin-B1 interactions in the central nervous system for pathogenesis of experimental autoimmune encephalomyelitis.

Although semaphorins were originally identified as axonal guidance molecules during neuronal development, it is emerging that several semaphorins play crucial roles in various phases of immune responses. Sema4D/CD100, a class IV semaphorin, has been shown to be involved in the nervous and immune systems through its receptors plexin-B1 and CD72, respectively. However, the involvement of Sema4D in neuroinflammation still remains unclear. We found that Sema4D promoted inducible NO synthase expression by primary mouse microglia, the effects of which were abolished in plexin-B1-deficient but not in CD72-deficient microglia. In addition, during the development of experimental autoimmune encephalomyelitis (EAE), which was induced by immunization with myelin oligodendrocyte glycoprotein-derived peptides, we observed that the expression of Sema4D and plexin-B1 was induced in infiltrating mononuclear cells and microglia, respectively. Consistent with these expression profiles, when myelin oligodendrocyte glycoprotein-specific T cells derived from wild-type mice were adoptively transferred into plexin-B1-deficient mice or bone marrow chimera mice with plexin-B1-deficient CNS resident cells, the development of EAE was considerably attenuated. Furthermore, blocking Abs against Sema4D significantly inhibited neuroinflammation during EAE development. Collectively, our findings demonstrate the role of Sema4D-plexin-B1 interactions in the activation of microglia and provide their pathologic significance in neuroinflammation.

Clear Cell Carcinoma in the Oral Cavity with Three Novel Types of EWSR1-ATF1 Translocation: A Case Report.

Clear cell carcinoma (CCC) is a rare epithelial malignant tumor of the salivary glands. It is characterized by tumor cells with clear cytoplasm, hyalinized stroma, and most importantly the fusion genes EWSR1-ATF1, EWSR1-CREM, and EWSR1-PLAG1. Break-apart FISH has been performed for multiple CCC cases, but direct sequencing analysis has been performed in relatively few. Herein, we report an interesting case of CCC harboring three EWSR1-ATF1 translocations: EWSR1 exon 8-ATF1 exon 4, EWSR1 exon 7-ATF1 exon 4, and EWSR1 exon 7-ATF1 exon 5. This case indicates the possibility of independent EWSR1-ATF1 gene translocations, and could provide insight into CCC tumorgenesis.

Genotype and phenotype analysis of patients with pediatric cutaneous mastocytosis, especially wild-type KIT patients.

Pediatric cutaneous mastocytosis (CM) is mainly attributed to gain-of-function mutations in KIT in mast cells. On the other hand, growing evidence suggests that CM patients exist without KIT mutations. To date, the association between the KIT mutation status and clinical phenotype has not been elucidated in pediatric CM, especially in patients with wild-type KIT. Nevertheless, genetic analysis has yet to be performed with whole KIT sequence of mast cells in Japanese patients with pediatric CM. In the present study, 11 Japanese patients with pediatric CM were analyzed to determine whether they had KIT mutations in their skin, and their clinical phenotypes were observed. The approximate frequency of patients with KIT mutation and that of wild-type KIT was almost consistent with the European analysis. The distribution of overall macules was similar between the patients with and without KIT mutations.