Showing papers by "Arimichi Takabayashi published in 2003"

CD4+CD25+ regulatory T cells in patients with gastrointestinal malignancies: possible involvement of regulatory T cells in disease progression.

Abstract: BACKGROUND Active suppression by CD4+CD25+ regulatory T cells plays an important role in the down-regulation of the response of T cells to foreign and self antigens. Experimental tumor models in mice revealed that regulatory T cells inhibit antitumor immune responses. The purpose of the current study was to demonstrate the possible involvement of CD4+CD25+ regulatory T cells in immune system impairment in patients with gastrointestinal malignancies. METHODS The phenotypes of lymphocytes, particularly those of CD4+CD25+ T cells, were analyzed in peripheral blood in 149 patients with gastrointestinal malignancies and in ascites in 7 patients with peritoneal dissemination. In addition, cytokine production after in vitro stimulation was examined in CD4+CD25+ and CD4+CD25− T cells isolated from patients with malignant disease. RESULTS Compared with healthy volunteers, patients with gastrointestinal malignancies had a higher proportion of CD4+CD25+ T cells in peripheral blood, due to the presence of a drastically smaller number of CD4+CD25− T cells. Among patients with gastric carcinoma, those with higher percentages of CD4+CD25+ T cells had a poorer prognosis than did those with lower percentages. CD4+CD25+ T cells also were present in greater proportions in ascites from patients who had advanced-stage disease with peritoneal dissemination. Isolated CD4+CD25+ T cells from patients with malignant disease produced interleukin (IL)-4 and IL-10 but not IL-2 or interferon-γ; these cells also inhibited cytokine production by CD4+CD25− T cells after in vitro stimulation. CONCLUSIONS The relative increase in CD4+CD25+ regulatory T cells may be related to immunosuppression and tumor progression in patients with gastrointestinal malignancies. This finding suggests that the use of immunomodulatory therapy to treat patients with gastrointestinal malignancies may be an effective strategy. Cancer 2003;98:1089–99. © 2003 American Cancer Society. DOI 10.1002/cncr.11618

Tuberculous Lymphadenitis as a Cause of Obstructive Jaundice: Report of a Case

Abstract: We report a rare case of obstructive jaundice caused by enlarged tuberculous lymph nodes compressing the common bile duct in the retropancreatic region, mimicking pancreatic cancer. A 32-year-old man was admitted to our hospital with a 1-month of history of jaundice. An abdominal computed tomography (CT) scan showed a tumor in the pancreatic head, but an endoscopic retrograde cholangiopancreatogram (ERCP) showed a normal pancreatic duct system. Positron emission tomography with 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (FDG-PET) revealed a hot spot only in the pancreatic head. Under a presumptive diagnosis of malignancy, a laparotomy was performed and an intraoperative biopsy specimen revealed epithelioid granuloma with caseous necrosis, which led us to suspect tuberculous lymphadenitis. This diagnosis was confirmed by culture, and antituberculous therapy was commenced postoperatively. The patient has not suffered any further episodes of obstructive jaundice. This case report demonstrates that positive FDG-PET results should be interpreted carefully when diagnosing tumors of the pancreatic head.

Change in Mitochondrial Membrane Potential in Peripheral Blood Lymphocytes, Especially in Natural Killer Cells, Is a Possible Marker for Surgical Stress on the Immune System

Abstract: There is accumulating evidence that surgical stresses cause impairment of systemic immune responses, which may promote susceptibility to infection as well as growth of remnant cancer cells in cancer patients. Although alterations in numbers, populations, and functions of lymphocytes have been extensively studied to assess modulation of the immune system, the precise mechanisms of immunosuppression caused by surgical stresses have not been identified, nor have methods been developed to estimate the magnitude of surgical stresses on the immune system. In the present study, to evaluate the effects of surgical procedures on the immune system, the mitochondrial membrane potential (ΔΨm) of peripheral blood lymphocytes (PBL) from 25 patients who underwent various types of operation was measured by flow cytometry using 3,3′-dihexiloxacarbocyanine iodide (DiOC6(3)) on the day before operation and on postoperative day (POD) 1, POD 3, and POD 7. The ΔΨm in PBL, especially in natural killer (NK) cell population, was reduced after major surgery. In particular, the reduction of ΨΔm in NK cells appeared to be proportional to the severity of the surgical procedures and reflected the impairment of cellular function. Interestingly, the ΔΨm in NK cells was also negatively correlated with the level of plasma noradrenaline after major surgery, suggesting that the reduction of ΔΨm in NK cells induced by surgical stresses may bemediated, at least in part, by the accompanying increase in plasma noradrenaline. Monitoring of ΔΨm in PBL after operation may be one of the useful markers for estimating the magnitude of surgical stresses on the immune system.