Kentaro Tominaga

Possible involvement of mucosal-associated invariant T cells in the progression of inflammatory bowel diseases

Mucosal-associated invariant T (MAIT) cells are innate-like T cells involved in anti-bacterial immunity. Recent studies have demonstrated that MAIT cells might be implicated in inflammatory bowel diseases (IBDs), but their precise function in IBD remains to be elucidated. We investigated the possible involvement of MAIT cells in the immunopathogenesis of IBDs. Heparinized peripheral blood and biopsy specimens of the colon were collected from 25 patients with ulcerative colitis (UC), 15 patients with Crohns disease (CD), and 19 heathy individuals. Lymphocytes were isolated from the blood and colon, and then MAIT cells were analyzed by flow cytometry. The frequency of MAIT cells was significantly lower in the blood of IBD patients compared to healthy donors and significantly higher in the inflamed colons compared to healthy colons (P = 0.001). Among the IBD patients, the frequency of MAIT cells in the blood and colon was correlated with disease activities. In vitro activated MAIT cells from IBD patients secreted significantly more tumor necrosis factor-α and interleukin-17 than those from healthy donors. These findings indicate that MAIT cells are activated in IBD patients, and their accumulation in the inflamed mucosa is correlated with disease activities.

Possible involvement of chemokine C‐C receptor 7−programmed cell death‐1+ follicular helper T‐cell subset in the pathogenesis of autoimmune hepatitis

Recent studies have demonstrated that B cells and follicular helper T (Tfh) cells, which are central regulators of humoral immune response, contribute to the development and progression of autoimmune diseases. Because Tfh cells can be divided into several subsets with distinct functional properties, this study aimed to examine the roles of different subsets of circulating Tfh cells in the immune pathogenesis of autoimmune hepatitis (AIH).

Possible involvement of CCR7-PD-1+ follicular helper T cell subset in the pathogenesis of autoimmune hepatitis

Recent studies have demonstrated that B cells and follicular helper T (Tfh) cells, which are central regulators of humoral immune response, contribute to the development and progression of autoimmune diseases. Because Tfh cells can be divided into several subsets with distinct functional properties, this study aimed to examine the roles of different subsets of circulating Tfh cells in the immune pathogenesis of autoimmune hepatitis (AIH).

Diversion colitis and pouchitis: A mini-review

Diversion colitis is characterized by inflammation of the mucosa in the defunctioned segment of the colon after colostomy or ileostomy. Similar to diversion colitis, diversion pouchitis is an inflammatory disorder occurring in the ileal pouch, resulting from the exclusion of the fecal stream and a subsequent lack of nutrients from luminal bacteria. Although the vast majority of patients with surgically-diverted gastrointestinal tracts remain asymptomatic, it has been reported that diversion colitis and pouchitis might occur in almost all patients with diversion. Surgical closure of the stoma, with reestablishment of gut continuity, is the only curative intervention available for patients with diversion disease. Pharmacologic treatments using short-chain fatty acids, mesalamine, or corticosteroids are reportedly effective for those who are not candidates for surgical reestablishment; however, there are no established assessment criteria for determining the severity of diversion colitis, and no management strategies to date. Therefore, in this mini-review, we summarize and review various recently-reported treatments for diversion disease. We are hopeful that the information summarized here will assist physicians who treat patients with diversion colitis and pouchitis, leading to better case management.

Persistent reduction of mucosal-associated invariant T cells in primary biliary cholangitis: Reduction of MAIT cells in PBC

Mucosal‐associated invariant T (MAIT) cells constitute a novel subset of innate‐like T lymphocytes characterized by a semi‐invariant T‐cell receptor repertoire capable of recognizing bacterial products. Considering the abundance of MAIT cells in the liver and the possible association between bacterial infections and primary biliary cholangitis (PBC), we aimed to analyze the involvement of MAIT cells in the immunopathogenesis of PBC.

Intraductal Papillary Neoplasm of the Bile Duct: A Rare Liver Tumor Complicated by Malignancy

Intraductal papillary neoplasm of bile duct (IPNB) in the liver is a rare tumor, accounting for 10% of all bile duct cancers. However, 40% contain carcinoma; thus, an accurate diagnosis followed by surgical treatment is essential. We report the usefulness of contrast-enhanced ultrasound (CEUS) in the detection of potential carcinoma in the tumor by demonstrating minute imaging details and correlating these with histological findings.

Usefulness of Capsule Endoscopy and Double-balloon Enteroscopy for the Diagnosis of Multiple Carcinoid Tumors in the Small Intestine: Case Reports and a Literature Review

The incidence of carcinoid tumor in the small intestine is increasing; however, its preoperative diagnosis is difficult. We recently experienced three cases of multiple carcinoid tumors in the small intestine successfully detected using capsule endoscopy (CE), followed by a pathological diagnosis using double-balloon enteroscopy (DBE). To diagnose multiple carcinoid in the small intestine appropriately, we reviewed the information of five cases reported to date along with our three recent cases. The literature review demonstrated that CE and DBE are useful for detecting and diagnosing small intestinal carcinoids and tumor multiplicity, which aids in determining the appropriate resection range.

Diagnosis and management of fibromuscular dysplasia and segmental arterial mediolysis in gastroenterology field: A mini-review

The vascular diseases including aneurysm, occlusion, and thromboses in the mesenteric lesions could cause severe symptoms and appropriate diagnosis and treatment are essential for managing patients. With the development and improvement of imaging modalities, diagnostic frequency of these vascular diseases in abdominal lesions is increasing even with the small changes in the vasculatures. Among various vascular diseases, fibromuscular dysplasia (FMD) and segmental arterial mediolysis (SAM) are noninflammatory, nonatherosclerotic arterial diseases which need to be diagnosed urgently because these diseases could affect various organs and be lethal if the appropriate management is not provided. However, because FMD and SAM are rare, the cause, prevalence, clinical characteristics including the symptoms, findings in the imaging studies, pathological findings, management, and prognoses have not been systematically summarized. Therefore, there have been neither standard diagnostic criteria nor therapeutic methodologies established, to date. To systematically summarize the information and to compare these disease entities, we have summarized the characteristics of FMD and SAM in the gastroenterological regions by reviewing the cases reported thus far. The information summarized will be helpful for physicians treating these patients in an emergency care unit and for the differential diagnosis of other diseases showing severe abdominal pain.

A Case of Panenteritis With Massive IgG4-Positive Plasma Cell Infiltration Developed 26 Years After Total Proctocolectomy for Ulcerative Colitis

A Case of Panenteritis With Massive IgG4-Positive Plasma Cell Infiltration Developed 26 Years After Total Proctocolectomy for Ulcerative Colitis

Gastrointestinal: A case of hypereosinophilic syndrome with esophageal involvement

A 38-year-old woman was admitted for an investigation into the cause of her dysphagia. Laboratory examination revealed an elevated peripheral eosinophil level (7198/μL, 36.5%). A bone marrow biopsy showed hypercellularity with markedly increased eosinophils, but clonal abnormalities were absent (Fig. 1). Therefore, she was diagnosed with idiopathic hypereosinophilic syndrome (HES). Endoscopy showed no evidence of anatomical lesions or neoplasia, and esophageal mucosa biopsies showed no evidence of eosinophilic infiltration. High-resolution manometry revealed hypercontractions, with a distal contractile integral value of 11 871.7 mmHg/s/cm (Fig. 2a). Endoscopic ultrasound showed a hypo-echoic, thickened esophageal muscle layer with a measured thickness of 4.3 mm (Fig. 2b). Because the peripheral eosinophil levels rapidly increased up to more than 70 000/μL, methylprednisolone pulse therapy was initiated. Thereafter, her symptoms improved, including a prompt decrease in the eosinophil count. High-resolution manometry and endoscopic ultrasound were repeated and revealed normal esophageal peristalsis with a distal contractile integral value of 3929.5 mmHg/s/cm (Fig. 2a, inset) and decreased muscle layer thickening (diameter, 1.5 mm; Fig. 2b, inset). The marked bone marrow eosinophil infiltration and the effectiveness of steroid therapy indicated that her dysphagia was caused by eosinophilic infiltration of the esophageal muscle layer due to HES. According to the World Health Organization classification, the definition of idiopathic HES depends on the following: (i) primary and secondary causes of hypereosinophilia must be excluded, (ii) an absolute eosinophilic count of >1500/mm must persist for at least 6 months, and (iii) organ damage must be present. In patients with HES, dermatologic or pulmonary involvement is relatively common; however, esophageal involvement manifesting with hypercontractions had not previously been reported. We have reported that eosinophilic infiltration of the esophagealmuscular layer without epithelial findings occurs in patients with a Jackhammer