Interleukin 9 mediates T follicular helper cell activation to promote antibody responses.

Antigen-specific humoral responses are orchestrated through complex interactions among immune cells in lymphoid tissues, including the collaboration between B cells and T follicular helper (Tfh) cells. Accumulating evidence indicates a crucial role for interleukin-9 (IL-9) in the formation of germinal centers (GCs), enhancing the generation of class-switched high-affinity antibodies. However, the exact function of IL-9 in Tfh cell regulation remains unclear. In this study, we examined the humoral immune responses of CD4Cre/+Il9rafl/fl mice, which lack an IL-9-specific receptor in Tfh cells. Upon intraperitoneal immunization with sheep red blood cells (SRBCs), CD4Cre/+Il9rafl/fl mice displayed diminished levels of SRBC-specific IgG antibodies in their sera, along with reduced levels of GC B cells and plasma cells. Notably, Il9ra-deficient Tfh cells in the spleen exhibited decreased expression of their signature molecules such as B-cell lymphoma 6, C-X-C chemokine receptor 5, IL-4, and IL-21 compared to control mice. In models of allergic asthma induced by house dust mite (HDM) inhalation, CD4Cre/+Il9rafl/fl mice failed to elevate serum levels of HDM-specific IgE and IgG. This was accompanied by reductions in Tfh cells, GC B cells, and plasma cells in mediastinal lymph nodes. Furthermore, group 2 innate lymphoid cells (ILC2s) were identified as producers of IL-9 under immunizing conditions, possibly induced by leukotrienes released by activated IgD+ B cells around the T-B border. These observations may indicate the critical role of IL-9 receptor signaling in the activation of Tfh cells, with ILC2s potentially capable of supplying IL-9 in organized lymphoid tissues.

Serum laminin γ2 monomer as a predictive biomarker for hepatocellular carcinoma in patients with chronic hepatitis B virus infection: a retrospective cohort study.

This retrospective study evaluated the use of laminin γ2 monomer (LG2m) as a predictive biomarker for hepatocellular carcinoma (HCC) in patients with chronic hepatitis B virus (HBV) infection. Serum LG2m levels were measured in two cohorts of patients: cohort 1 comprised 56 patients with chronic liver disease for assessing LG2m stability, whereas cohort 2 included 89 patients with chronic HBV infection who did not have HCC for evaluating the usefulness of LG2m measurement in HCC prediction. LG2m was highly stable in cryopreserved serum, and an increased LG2m level was significantly associated with a higher risk of HCC in chronically HBV-infected patients (P = 0.012). Multivariable Cox regression analysis revealed that high LG2m was an independent significant risk factor for HCC (hazard ratio, 7.16; 95% confidence interval, 1.31-39.2; P = 0.023). These findings suggest that LG2m may serve as a useful biomarker for the prediction of future HCC in patients with chronic HBV infection.

Bob1 maintains T follicular helper cells for long-term humoral immunity.

Humoral immunity is vital for host protection, yet aberrant antibody responses can trigger harmful inflammation and immune-related disorders. T follicular helper (Tfh) cells, central to humoral immunity, have garnered significant attention for unraveling immune mechanisms. This study shows the role of B-cell Oct-binding protein 1 (Bob1), a transcriptional coactivator, in Tfh cell regulation. Our investigation, utilizing conditional Bob1-deficient mice, suggests that Bob1 plays a critical role in modulating inducible T-cell costimulator expression and cellular respiration in Tfh cells. This regulation maintains the long-term functionality of Tfh cells, enabling their reactivation from central memory T cells to produce antibodies during recall responses. In a bronchial asthma model induced by house dust mite (HDM) inhalation, Bob1 is observed to enhance HDM-specific antibodies, including IgE, highlighting its pivotal function in Tfh cell regulation. Further exploration of Bob1-dependent mechanisms in Tfh cells holds promise for governing protective immunity and addressing immune-related disorders.

Circulating T follicular helper 2 cells, T follicular regulatory cells and regulatory B cells are effective biomarkers for predicting the response to house dust mite sublingual immunotherapy in patients with allergic respiratory diseases.

The relationships between T follicular helper (Tfh) cells and antigen-specific immunoglobulins (sIgs) in patients with allergic respiratory diseases who are receiving antigen immunotherapy (AIT) have not been fully clarified. Therefore, we started to perform house dust mite sublingual immunotherapy (HDM-SLIT) for 20 patients with atopic asthma comorbid with allergic rhinitis (AA+AR) who were already receiving ordinary treatments including inhaled corticosteroid (ICS). We examined percentages of circulating T follicular helper (cTfh) and regulatory (cTfr) cells and percentages of circulating regulatory T (cTreg) and B (cBreg) cells by FACS and we examined levels of Der-p/f sIgs by ELISA. Based on the symptom score (asthma control questionnaire: ACQ) and medication score ((global initiative for asthma: GINA) treatment step score) in patients with AA, the patients were divided into responders and non-responders. The percentage of cTfh2 cells significantly decreased and the percentage of cTfh1 cells significantly increased within the first year. Der-p/f sIgEs decreased after a transient elevation at 3 months in both groups. Notably, the percentage of cTfh2 cells and the ratio of cTfh2/cBreg cells and Der-p/f sIgEs greatly decreased in responders from 6 months to 12 months. The percentages of cTfr and cTreg cells showed significant negative correlations with the percentage of cTfh2 cells. The percentage of IL-4+ cTfh cells were significantly decreased and the percentage of IFN-γ+ cTfh cells were increased before treatment to 24 months in 6 patients examined (4 responders and 2 non-responders). We performed multi plelogistic regression analysis based on these results, the ratios of cTfh2/cTfr cells and cTfh2/cBreg cells at the start of therapy were statistically effective biomarkers for predicting the response to HDM-SLIT in patients with AA+AR.

Post-allogeneic Hematopoietic Stem Cell Transplantation Portal Hypertension Not Associated with Liver Cirrhosis, Veno-occlusive Disease, or Graft-versus-host Disease: A Case Report.

We herein report a rare case of idiopathic portal hypertension (IPH)-like disease that developed after allogeneic hematopoietic stem cell transplantation (allo-HSCT). A 53-year-old woman who underwent allo-HSCT for acute myeloid leukemia showed portal hypertension with radiological and histopathological findings consistent with IPH, distinct from veno-occlusive disease (VOD) and graft-versus-host disease (GVHD) of the liver. This case highlights the importance of considering IPH-like disease as a potential cause of portal hypertension after allo-HSCT. Awareness of this complication can aid in the early diagnosis and appropriate management of patients post allo-HSCT.

Adenosquamous carcinoma of the gallbladder simultaneously producing granulocyte-colony-stimulating factor and parathyroid hormone-related protein.

We report a rare case of adenosquamous carcinoma of the gallbladder which simultaneously produces granulocyte-colony-stimulating factor (G-CSF) and parathyroid hormone-related protein (PTHrP), confirmed serologically and histologically. A 71-year-old man was examined for a gallbladder tumor with multiple lymph nodes and liver metastases. Histopathological evaluation by endoscopic ultrasound fine-needle aspiration revealed adenosquamous carcinoma of the gallbladder. Laboratory data showed markedly elevated white blood cell (WBC) count of 34,700 µL and corrected serum calcium level of 14.9 mg/dL. Serum G-CSF (191 pg/mL) and PTHrP (23.1 pmol/L) levels were high. Zoledronic acid and calcitonin were administered to treat hypercalcemia, which normalized serum calcium levels. Gemcitabine-cisplatin chemotherapy was started for cStage IVB gallbladder cancer. After chemotherapy initiation, WBCs showed a rapid downward trend; however, the patient suddenly developed acute respiratory distress syndrome; thus, chemotherapy was discontinued. Subsequently, WBC count increased again, and the patient's overall condition deteriorated. The patient died on day 27. Immunohistochemistry using autopsy specimens demonstrated patchy staining for G-CSF in the squamous cell carcinoma portion and diffuse and weak positive staining for PTHrP in the squamous cell carcinoma and poorly differentiated adenocarcinoma portions of the tumor, suggesting simultaneous G-CSF and PTHrP production by the tumor. This is the first report of a patient with gallbladder cancer with serological and histological evidence for G-CSF and PTHrP production.

A rare cause of jejunal perforation: Monomorphic epitheliotropic intestinal T-cell lymphoma.

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a very rare intestinal T-cell lymphoma which is observed most frequently in the jejunum. MEITL is prone to cause intestinal perforation and the prognosis is very poor when it occurs. Here we report a fatal case of MEITL causing jejunal perforation at the time of diagnosis in a 79-year-old man. The patient underwent emergency surgery for jejunal perforation caused by MEITL but died 3 months after the initial visit due to prolonged peritonitis. It is desirable to establish a method to predict cases with intestinal perforation, and systematize the treatment strategies to avoid perforation.

CD4+CD8+ T follicular helper cells regulate humoral immunity in chronic inflammatory lesions.

T follicular helper (Tfh) cells drive humoral immunity by facilitating B cell responses at the initial and recall phases. Recent studies have indicated the possible involvement of Tfh cells in the process of chronic inflammation. However, the functional role of Tfh cells in persistent immune settings remains unclear. Here, we report that CD4+CD8+ (double-positive, DP; CD3+CD4+CD8+CXCR5hiPD-1hi) Tfh cells, a subset of germinal-center-type Tfh cells, were abundantly present in the fibroinflammatory lesions of patients with immunoglobulin G4-related disease (IgG4-RD). Transcriptome analyses showed that these DP-Tfh cells in the lesions of IgG4-RD preferentially expressed signature genes characteristic of cytotoxic CD8+ T cells, such as Eomes, CRTAM, GPR56, and granzymes, in addition to CD70. Scatter diagram analyses to examine the relationships between tissue-resident lymphocytes and various clinical parameters revealed that the levels of DP-Tfh cells were inversely correlated to the levels of serum IgG4 and local IgG4-expressing (IgG4+) memory B cells (CD19+CD27+IgD-) in patients with IgG4-RD. Cell culture experiments using autologous tonsillar lymphocytes further suggested that DP-Tfh cells possess a poor B-cell helper function and instead regulate memory B cells. Since CD4+ (single positive, SP; CD3+CD4+CD8-CXCR5hiPD-1hi) Tfh cells differentiated into DP-Tfh cells under stimulation with IL-2 and IL-7 as assessed by in vitro experiments, these data imply that SP-Tfh cells are a possible origin of DP-Tfh cells under persistent inflammation. These findings highlight the potential feedback loop mechanism of Tfh cells in immune tolerance under chronic inflammatory conditions. Further studies on DP-Tfh cells may facilitate control of unresolved humoral responses in IgG4-RD pathological inflammation.

Successful hemostasis for post-endoscopic sphincterotomy bleeding following endoscopic papillary large balloon dilation using 12-mm-diameter fully covered self-expandable metal stent.

A 12-mm-diameter fully covered self-expandable metal stent may be effective for securing hemostasis in post-endoscopic sphincterotomy bleeding following endoscopic papillary large balloon dilation.

Functional Interplay between IL-9 and Peptide YY Contributes to Chronic Skin Inflammation.

Complex interactions between keratinocytes and various cell types, such as inflammatory cells and stromal cells, contribute to the pathogenesis of chronic inflammatory skin lesions. In proinflammatory cytokine‒mediated disease settings, IL-9 plays a pathological role in inflammatory dermatitis. However, IL-9‒related mechanisms remain incompletely understood. In this study, we established tamoxifen-induced keratinocyte-specific IL-9RA-deficient mice (K14CRE/ERTIl9raΔ/Δ mice) to examine the role of IL-9 in multicellular interactions under chronic skin inflammatory conditions. Studies using an imiquimod-induced psoriasis-like model showed that K14CRE/ERTIl9raΔ/Δ mice exhibited a significantly reduced severity of dermatitis and mast cell infiltration compared with control K14WTIl9rafl/fl mice. Transcriptome analyses of psoriasis-like lesions showed that the level of peptide Y-Y (Pyy), a member of the neuropeptide Y family, was markedly downregulated in K14CRE/ERTIl9raΔ/Δ epidermis. Pyy blockade suppressed epidermal thickening and mast cell numbers in imiquimod-treated wild-type mice. Together with in vitro studies indicating that Pyy induced IL-9 production and chemotactic activity in bone marrow‒derived mast cells, these findings suggest that Pyy-mediated interplay between keratinocytes and mast cells contributes to psoriasiform inflammation. Further investigation focusing on the IL-9‒Pyy axis may provide valuable information for the development of new treatment modalities for inflammatory dermatitis.

Hydroxynonenal Causes Hepatocyte Death by Disrupting Lysosomal Integrity in Nonalcoholic Steatohepatitis.

BACKGROUND & AIMS: The lipid oxidation is a key factor for damaging hepatocytes and causing cell death. However, the mechanisms underlying hepatocyte death and the role of the most popular lipid peroxidation product 4-hydroxy-2-nonenal (HNE) in nonalcoholic steatohepatitis (NASH) remains unclear. METHODS: We demonstrated using hepatoma cell lines, a NASH mouse model, HNE-treated monkeys, and biopsy specimens from patients with NASH that HNE induced hepatocyte death by disintegrating the lysosomal limiting membrane. RESULTS: The degree of HNE deposition in human NASH hepatocytes was more severe in cases with high lobular inflammation, ballooning, and fibrosis scores, and was associated with enlargement of the staining of lysosomes in hepatocytes. In in vitro experiments, HNE activated µ-calpain via G-protein coupled receptor (GPR) 120. The resultant rupture/permeabilization of the lysosomal limiting membrane induced the leakage of cathepsins from lysosomes and hepatocyte death. The blockade of G-protein coupled receptor 120 (GPR120) or µ-calpain expression suppressed lysosomal membrane damage and hepatocyte death by HNE. Alda-1, which activates aldehyde dehydrogenase 2 to degrade HNE, prevented HNE-induced hepatocyte death. Intravenous administration of HNE to monkeys for 6 months resulted in hepatocyte death by a mechanism similar to that of cultured cells. In addition, intraperitoneal administration of Alda-1 to choline-deficient, amino-acid defined treated mice for 8 weeks inhibited HNE deposition, decreased liver inflammation, and disrupted lysosomal membranes in hepatocytes, resulting in improvement of liver fibrosis. CONCLUSIONS: These results provide novel insights into the mechanism of hepatocyte death in NASH and will contribute to the development of new therapeutic strategies for NASH.

Hsp70.1 carbonylation induces lysosomal cell death for lifestyle-related diseases.

Alzheimer's disease, type 2 diabetes, and non-alcoholic steatohepatitis (NASH) constitute increasingly prevalent disorders. Individuals with type 2 diabetes are well-known to be susceptible to Alzheimer's disease. Although the pathogenesis of each disorder is multifactorial and the causal relation remains poorly understood, reactive oxygen species (ROS)-induced lipid and protein oxidation conceivably plays a common role. Lipid peroxidation product was recently reported to be a key factor also for non-alcoholic steatohepatitis, because of inducing hepatocyte degeneration/death. Here, we focus on implication of the representative lipid-peroxidation product 'hydroxynonenal' for the cell degeneration/death of brain, pancreas, and liver. Since Hsp70.1 has dual roles as a chaperone and lysosomal membrane stabilizer, hydroxynonenal-mediated oxidative injury (carbonylation) of Hsp70.1 was highlighted. After intake of high-fat diets, oxidation of free fatty acids in mitochondria generates ROS which enhance oxidation of ω-6 polyunsaturated fatty acids (PUFA) involved within biomembranes and generate hydroxynonenal. In addition, hydroxynonenal is generated during cooking deep-fried foods with vegetable oils especially containing linoleic acids. These intrinsic and exogenous hydroxynonenal synergically causes an increase in its serum and organ levels to induce Hsp70.1 oxidation. As it is amphiphilic; being water-soluble but displays strong lipophilic characteristics, hydroxynonenal can diffuse within the cells and react with targets like senile and/or atheromatous plaques outside the cells. Hydroxynonenal can deepen and expand lysosomal injuries by facilitating 'calpain-mediated cleavage of the carbonylated Hsp70.1'. Despite the unique anatomical, physiological, and biochemical characteristics of each organ for its specific disease, there should be a common cascade of the cell degeneration/death which is caused by hydroxynonenal. This review aims to implicate hydroxynonenal-mediated Hsp70.1 carbonylation for lysosomal membrane permeabilization/rupture and the resultant cathepsin leakage for inducing cell degeneration/death. Given the tremendous number of worldwide people suffering various lifestyle-related diseases, it is valuable to consider how ω-6 PUFA-rich vegetable oils is implicated for the organ disorder.

[Case report of a patient with recurrence after endoscopic submucosal dissection for superficial esophageal cancer, diagnosed with mediastinal lymph node endoscopic ultrasound-fine needle aspiration based on the symptom of hoarseness].

The patient was an 81-year-old man who presented with a complaint of hoarseness. When he was 80 years old, he had developed superficial esophageal cancer and had undergone endoscopic submucosal dissection (ESD) at our hospital. Two months after the ESD, he developed hoarseness. Computed tomography (CT) scan showed no abnormal findings at that time;therefore, he was diagnosed with idiopathic vocal cord paralysis, and followed up with symptom treatment in the Gastroenterology and Otolaryngology Departments. Ten months after the ESD, a CT scan revealed mediastinal lymph node swelling. He was admitted to our hospital for histopathological examination of the lymph node using endoscopic ultrasound-fine needle aspiration (EUS-FNA). The histopathological examination revealed squamous cell carcinoma of the lymph node, similar to the primary esophageal tumor. This result suggests that laryngeal nerve paralysis involving hoarseness is caused by lymph node metastasis of superficial esophageal cancer. We report that histopathological examination with EUS-FNA helps in determining the cause of hoarseness that develops after ESD.

A case of refractory pouchitis complicated by cytomegalovirus infection requiring administration of ganciclovir and infliximab.

Pouchitis is a frequent complication of surgical treatment of ulcerative colitis (UC), and is typically treated using antimicrobials. If pouchitis is refractory to antimicrobials, screening for complications, such as cytomegalovirus (CMV) infection, is necessary. However, the optimal approach to management of pouchitis complicated by CMV infection is unclear. We report the case of a 41-year-old female patient with UC presenting with pouchitis associated with CMV infection; she had received subtotal colectomy/ileal pouch anal anastomosis (IPAA). She was admitted to hospital with persistent fever, epigastric discomfort, and watery diarrhea despite receiving antibiotics. Laboratory findings showed inflammation and reactivation of CMV infection accompanied by liver injury. The endoscopic findings showed inflammation of the pouch and ileal mucosa on the oral side with extensive and deep punched-out ulcers. Immunohistological staining of biopsy specimens from an ulcerated lesion demonstrated CMV infection. Therefore, we diagnosed the patient with pouchitis complicated by CMV infection. The patient was treated with ganciclovir and infliximab, which resolved her symptoms and led to the disappearance of CMV-positive cells. There has been no recurrence of pouchitis. CMV infection should be considered in patients with UC who develop refractory pouchitis.

Clinical Features and Dynamics of T Cells-Related Markers in Immunocompetent Patients with Cytomegalovirus Hepatitis.

Aim: Cytomegalovirus (CMV) can cause hepatitis, encephalomyelitis, and pneumonitis in immunocompromised patients. In contrast, CMV infection of immunocompetent patients can lead to the development of infectious mononucleosis and is typically self-limiting; severe complications are rare. We evaluated the pathophysiology and immunological aspects of CMV hepatitis in recently immunocompetent adult patients. Methods: We examined the clinical features and outcomes of 47 adult immunocompetent patients with CMV hepatitis (29 men, 18 women; mean age, 34 ± 11 years) from January 2005 to August 2019 treated in our hospital. We also assayed T-cell activation to evaluate the immune responses in these patients. Results: Fever (74.5%), hepatosplenomegaly (74.5%), sore throat (36.2%), headache (31.9%), abdominal pain (27.7%), lymphadenopathy (23.4%), and skin rash (6.4%) were present at admission. Complications included gastrointestinal injury (25.5%), neuropathy (4.3%), thrombocytopenia (2.1%), and splenic infarction (2.1%). All patients had a good clinical course without liver failure or transition to chronic liver injury. The time to recover from liver injury ranged from 12 to 142 days (mean, 43.4 ± 28.7 days). The serum sIL-2R level, which reflects T-cell activation, was transiently elevated and correlated with the extent of hepatic inflammation. Conclusions: CMV hepatitis in immunocompetent individuals has a satisfactory outcome, but occasionally results in complications in other organs. The sIL-2R level has potential as a surrogate marker of hepatic inflammation in immunocompetent patients with CMV hepatitis.