Sema6D forward signaling impairs T cell activation and proliferation in head and neck cancer.

Immune checkpoint inhibitors (ICIs) are indicated for a diverse range of cancer types, and characterizing the tumor immune microenvironment is critical for optimizing therapeutic strategies, including ICIs. T cell infiltration and activation status in the tumor microenvironment greatly affects the efficacy of ICIs. Here, we show that semaphorin 6D (Sema6D) forward signaling, which is reportedly involved in coordinating the orientation of cell development and migration as a guidance factor, impaired the infiltration and activation of tumor-specific CD8+ T cells in murine oral tumors. Sema6D expressed by nonhematopoietic cells was responsible for this phenotype. Plexin-A4, a receptor for Sema6D, inhibited T cell infiltration and partially suppressed CD8+ T cell activation and proliferation induced by Sema6D stimulation. Moreover, mouse oral tumors, which are resistant to PD-1-blocking treatment in wild-type mice, showed a response to the treatment in Sema6d-KO mice. Finally, analyses of public data sets of human head and neck squamous cell carcinoma, pan-cancer cohorts, and a retrospective cohort study showed that SEMA6D was mainly expressed by nonhematopoietic cells such as cancer cells, and SEMA6D expression was significantly negatively correlated with CD8A, PDCD1, IFNG, and GZMB expression. Thus, targeting Sema6D forward signaling is a promising option for increasing ICI efficacy.

Pathological and therapeutic implications of eosinophil-derived semaphorin 4D in eosinophilic chronic rhinosinusitis.

BACKGROUND: Eosinophilic chronic rhinosinusitis (ECRS) is a subtype of chronic rhinosinusitis. Clinical markers for ECRS disease activity and treatment strategies have not been sufficiently established. Although semaphorins are originally identified as neuronal guidance factors, it is becoming clear that they play key roles in immune regulation and inflammatory diseases. OBJECTIVE: We sought to investigate the pathological functions and therapeutic potential of semaphorin 4D (SEMA4D) in ECRS. METHODS: Serum soluble SEMA4D levels in patients with paranasal sinus diseases were measured by ELISA. The expression of SEMA4D in blood cells and nasal polyp tissues was assessed by flow cytometry and immunohistochemistry, respectively. Generation of soluble SEMA4D was evaluated in matrix metalloproteinase-treated eosinophils. Endothelial cells were stimulated with recombinant SEMA4D, followed by eosinophil transendothelial migration assays. Allergic chronic rhinosinusitis was induced in mice using Aspergillus protease with ovalbumin. The efficacy of treatment with anti-SEMA4D antibody was evaluated histologically and by nasal lavage fluid analysis. RESULTS: Serum soluble SEMA4D levels were elevated in patients with ECRS and positively correlated with disease severity. Tissue-infiltrated eosinophils in nasal polyps from patients with ECRS stained strongly with anti-SEMA4D antibody. Cell surface expression of SEMA4D on eosinophils from patients with ECRS was reduced, which was due to matrix metalloproteinase-9-mediated cleavage of membrane SEMA4D. Soluble SEMA4D induced eosinophil transendothelial migration. Treatment with anti-SEMA4D antibody ameliorated eosinophilic infiltration in sinus tissues and nasal lavage fluid in the ECRS animal model. CONCLUSIONS: Eosinophil-derived SEMA4D aggravates ECRS. Levels of serum SEMA4D reflect disease severity, and anti-SEMA4D antibody has therapeutic potential as a treatment for ECRS.

Acute Myeloid Leukemia Complicated by Giant Cell Arteritis.

Giant cell arteritis (GCA), a type of systemic arteritis, is rare in Japan. We herein report a case of acute myeloid leukemia (AML) complicated by GCA that manifested during chemotherapy for AML. A 77-year-old woman with severe back pain was diagnosed with AML. She achieved complete remission with the resolution of her back pain following induction chemotherapy. However, she developed a headache and fever after consolidation chemotherapy. A diagnosis of GCA was made based on a biopsy of the temporal artery and arterial imaging. GCA should therefore be included in the differential diagnosis in AML patients complicated with a headache and fever of unknown origin.

Successful treatment of refractory cold hemagglutinemia in MYD88 L265P mutation-negative Waldenström's macroglobulinemia with bortezomib.

We report here the successful treatment of cold agglutinin-associated refractory hemolysis with bortezomib in a patient with Waldenström's macroglobulinemia (WM). A 78-year-old man was referred to our hospital with cold hemagglutinemia of unknown cause. Laboratory examination revealed a hemoglobin concentration of 6.9 g/dL, serum IgM concentration of 1904 mg/dL, and a titer of cold hemagglutinin of over ×8192. Serum immunoelectrophoresis demonstrated monoclonal protein of the IgM-κ type. A bone marrow aspirate showed many lymphoplasmacytic cells, which were positive for CD19, CD20, CD38, and cytoplasmic µ and κ light chains. A diagnosis of WM-associated cold hemagglutinemia was made. Because of red blood cell transfusion-dependency, we treated him with intravenous fludarabine, oral melphalan-prednisolone, cyclophosphamide, and melphalan, and two courses of R-CHOP in sequence with a marked decrease of serum IgM (928 mg). We then started weekly bortezomib plus dexamethasone (BD) therapy, as he was still transfusion-dependent. Soon after the initiation of BD, he achieved transfusion independence, with a further decrease in serum levels of IgM and marked improvement of anemia. Interestingly, his marrow abnormal lymphocytes were later found not to carry the MYD88 L265P mutation. The successful treatment with bortezomib for WM lacking this mutation is discussed.

[Familial Annulo-aortic Ectasia without Marfan Syndrome].

Marfan syndrome is a hereditary disease that presents ocular, skeletal, and cardiovascular abnormalities. In recent years, there have been several reports of patients with familial cardiovascular disease but no physical features of Marfan syndrome. We encountered 3 cases of familial annulo-aortic ectasia (AAE). Their father had also had aortic regurgitation, and died during surgery 10 years before. No case demonstrated any physical characteristics of Marfan syndrome or any other connective tissue disease. All cases were operated successfully. One case showed cystic medial necrosis, and 2 cases showed degenerative change. The present report suggests that familial AAE may be caused by weakness of the aortic wall related to heredity. If AAE is left untreated, it can lead to aortic dissection. Thus, we recommend that patients with familial AAE should undergo screening and follow-up similar to patients with Marfan syndrome.

Artemin causes hypersensitivity to warm sensation, mimicking warmth-provoked pruritus in atopic dermatitis.

BACKGROUND: Itch impairs the quality of life for many patients with dermatoses, especially atopic dermatitis (AD), and is frequently induced by a warm environment. OBJECTIVE: To determine the mechanism underlying itch induction by warmth, we focused on artemin, a member of glial cell line-derived neurotrophic factors (GDNFs). METHODS: A gene array assay revealed that artemin was expressed in substance P-treated dermal fibroblasts. The expression of artemin in healthy and AD-lesional skin was evaluated with immunohistochemistry and in situ hybridization. The impact of fibroblast-derived artemin on the proliferation and morphology of neural cell was investigated in vitro. To confirm the involvement of artemin in skin sensibility, wild-type and GDNF family receptor α3 knockout mice were employed for sensory examination. RESULTS: Artemin-expressing fibroblasts accumulated in skin lesions of patients with AD. Artemin induced cell proliferation of a neuroblastoma cell line in vitro, and intradermal injection of artemin in mice resulted in peripheral nerve sprouting and thermal hyperalgesia. Artemin-treated mice demonstrated scratching behavior in a warm environment, but mice deficient for GDNF family receptor α3, a potent artemin receptor, did not show this behavior. Furthermore, the escaping response to heat stimulus was attenuated in GDNF family receptor α3 knockout mice, suggesting that artemin may contribute to sensitivity to heat. CONCLUSION: These data suggest that dermal fibroblasts secrete artemin in response to substance P, leading to abnormal peripheral innvervation and thermal hyperalgesia. We hypothesize that artemin lowers the threshold of temperature-dependent itch sensation and might therefore be a novel therapeutic target for treating pruritic skin disorders, including AD.