The characterization of a new monoclonal antibody (MoAb) recognizing a human B-cell activation antigen, designated FUN-1, is described in this paper. Immunoprecipitation revealed that FUN-1 recognizes an antigen with a molecular weight (MW) of 75kD. FUN-1 reacts with pokeweed mitogen-activated B lymphocytes and monocytes of peripheral blood, but not with unstimulated lymphocytes or granulocytes. It also reacts with large lymphoid cells in germinal centres, Epstein-Barr virus-transformed B cell lines, large B-cell lymphomas, Ki-1-positive anaplastic large-cell lymphomas, and Reed-Sternberg cells of Hodgkin's disease, but not with Concanavalin A-activated T cells, acute lymphoblastic leukaemias, T-cell lymphomas, or low-grade B-cell leukaemias. These findings indicate that FUN-1 recognizes a previously unreported B-cell activation antigen. This MoAb appears to be useful for the study of maturation and differentiation in the B-cell lineage as well as for the immunohistochemical diagnosis of B-cell lymphomas and Hodgkin's disease.

Between 1993 and 1997, 11 patients with rectal carcinoids less than 8 mm in diameter (mean size: 5.5 mm) were endoscopically treated at Tsuboi Hospital. Seven patients were treated by polypectomy or endoscopic mucosal resection. Three of the seven lesions were microscopically diagnosed as having positive submucosal margins. The remaining four showed a distance between the tumor and the resection line(DBTRL) of 0 to 0.33 mm. Then, we attempted endoscopic double snare polypectomy (EDSP) in 1996 and 1997. In four consecutive patients, the tumor was completely resected by this method. The DBTRL ranged from 0.08 to 0.75 mm in four lesions resected by EDSP. With endoscopic resection of these tumors, the incidence of positive margins is high using the conventional single snare methods, even when the lesions are less than 10 mm in diameter. EDSP was useful for total removal of small rectal carcinoids.

To clarify the histogenesis of B cell chronic lymphocytic leukemia (BCLL), clinicopathological and immunophenotypic studies were performed using a large panel of monoclonal antibodies on 12 cases with BCLL including three caes with prolymphocytic/chronic lymphocytic leukemia (CLL/PL). Immunophenotypically, CD19 and CD20 were positive for all cases of this series and CD5, CD21, CD22, CD23, CD25, CD38, Leu‐8, KB‐61, and bcl‐2 protein were expressed in variable proportion from case to case. CD10, however, did not react. No alkaline phosphatase (ALP) positive cases were found. The phenotype of BCLL was similar to that of B cells of the mantle zone (MZ) of secondary follicle in the lymph node. It is therefore postulated that the neoplastic cells of BCLL in these cases might be derived from B cells of the MZ. Moreover, the cells possibly originated from the lymphocytes located in the inner layer of the MZ, since ALP+ B cells are usually observed in the outer layer of the MZ. The pseudofollicular (PF) pattern was observed in four biopsied lymph nodes among five cases tested, but no such a pattern in an aspiration clot of bone marrow. These four cases consisted of three cases with CLL and a case with CLL/PL. The immunohistochemical study showed that there were many proliferating cells showing Ki‐67+ in the PF area of the lymph nodes. In these cases, leukemic cells might have developed from the PF area of the lymph node.

WW. Light and immunoelectronmicroscopic study of Hodgkin's disease: Evidence of immunoglobulin synthesis by Hodgkin's disease. Virchow Arch [Cell Pathol] 37: 109-124 1981. 4) Stuart AE, Volsen SG, Zola H. The reactivity of Reed-Sternberg cells with monoclonal antisera at thin section and ultra-structural levels.

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