CEACAM1 specifically suppresses B cell receptor signaling-mediated activation.

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) expressed in T cells may regulate immune responses in the gut. In addition to T cells, B cells are also an important population in the gut-associated lymphoid tissues that orchestrate mucosal homeostasis. However, the role of CEACAM1 in B cells has not been elucidated. We herein analyzed mature B cells to determine the functions of CEACAM1. Flow cytometry revealed high expression of CEACAM1 on B cells in secondary lymphoid tissues. Cytokine production induced by activation of B cell receptor (BCR) signaling was suppressed by CEACAM1 signaling in contrast to that associated with either Toll-like receptor 4 or CD40 signaling. Confocal microscopy revealed co-localization of CEACAM1 and BCR when activated with anti-Igµ F(ab')2 fragment. Overexpression of CEACAM1 in a murine B cell line, A20, resulted in reduced expressions of activation surface markers with decreased Ca2+ influx after BCR signal activation. Overexpression of CEACAM1 suppressed BCR signal cascade in A20 cells in association with decreased spontaneous proliferation. Our results suggest that CEACAM1 can regulate BCR-mediated mature B cell activation in lymphoid tissues. Therefore, further studies of this molecule may lead to greater insights into the mechanisms of immune responses within peripheral tissues and the potential treatment of inflammatory diseases.

Indolent T cell lymphoproliferative disorder with villous atrophy in small intestine diagnosed by single-balloon enteroscopy.

Chronic diarrhea is one of the major symptoms in gastroenterology. However, this may be caused by pathologic conditions for which the diagnosis is critical. Villous atrophy, as an endoscopic lesion, accompanied by chronic diarrhea can occasionally be observed in the patients with inflammatory diseases of the gastrointestinal (GI) tract. Herein, we present a case with persistent diarrhea accompanied by intestinal wall thickening without any other significant endoscopic features other than villous atrophy in the jejunum and the ileum, where we diagnosed as an indolent T cell lymphoproliferative disorder (T-LPD) of the GI tract, defined in the 2016-2017 revised World Health Organization classification, via single-balloon enteroscopy (SBE). Interestingly, we found the same lymphocyte infiltration from the distal third portion of the duodenum, where gastroscopy could not reach, via SBE, even though no endoscopic findings were observed such as villous atrophy. Since infiltrating cells in the intestinal tissues were CCR4+, mogamulizumab was administered with resulting durable symptomatic remission for more than 2 years. Patients with persistent diarrhea may have serious small intestinal disorder including not only chronic inflammatory diseases but also lymphoid neoplasmic conditions including T-LPD of GI tract.

Elevation of Neutrophil-to-Lymphocyte Ratio before First-Line Chemotherapy Predicts a Poor Prognosis for Second-Line Chemotherapy in Gastric Cancer.

OBJECTIVES: The neutrophil-to-lymphocyte ratio (NLR) has been proposed as an indicator of cancer-related inflammation. The aim of our study was to examine the prognostic value of the NLR for patients with advanced gastric cancer receiving second-line chemotherapy. METHODS: The association of overall survival (OS) in second-line chemotherapy and the clinicopathological findings including NLR were analyzed retrospectively. The selection criteria were patients who received second-line chemotherapy between January 2010 and June 2015, had histologically confirmed gastric adenocarcinoma, and were followed up until death or for 180 days or longer. RESULTS: Eighty-six patients met the selection criteria. Multivariate analysis revealed that performance status 2, hemoglobin < 10 g/dL, and NLR before first-line chemotherapy ≥3 were adverse predictive markers. NLR before second-line chemotherapy was not associated with OS. A prognostic model was constructed dividing patients into three groups according to the number of adverse predictive factors: good (no factor), intermediate (one factor), and poor (more than two factors). The median OS for the good, intermediate, and poor groups was 14.3, 7.2, and 4.4 months, respectively (p < 0.001). CONCLUSIONS: Patients with advanced gastric cancer with performance status 2, hemoglobin < 10 g/dL, and NLR before first-line chemotherapy ≥3 are not likely to benefit from second-line chemotherapy.