胃・腸管悪性リンパ腫の免疫組織学的特徴

Immunohistopathology of the Primary Gastrointestinal Malignant Lymphomas

要旨　悪性リンパ腫は節性と節外性とに分けられ，胃・腸管発生のものは節外性リンパ腫に属する．筆者らが免疫組織学的に検討した消化管原発の悪性リンパ腫は31例で，Bリンパ腫30例とTリンパ腫1例から成っている．組織学的に濾胞性リンパ腫は2例のみで，他の29例はびまん性リンパ腫である．細胞型では節性リンパ腫と同様，大細胞型が最も多く，約65％を占めている．パラフィン切片（LN1，LN2……）や，凍結切片（B1，B4……）による免疫染色によって腫瘍細胞のphenotypeを決定しうるが，特にパラフィン切片では数種の抗体を併用する必要がある．免疫染色では各細胞型に応じて特異な陽性所見を認めた．今後，腫瘍細胞の増殖能についても免疫染色によって明らかにする必要がある．

　Malignant lymphomas of the gastrointestinal tract are categorized as extranodal lymphomas distinguished from those of the lymph node. A total of 31 cases with malignant lymphomas of the GI tract, comprising 30 cases with B cell type and 1 case with T cell type, were studied by the use of immunohistological techniques. Histologically, only two cases showed follicular form and the remainder, diffuse form. Large cell type of malignant lymphoma was the most prevalent form, accounting for 65％ of this series.

　In recent years a great number of monoclonal antibodies available for the lymphomas have been developed and several of those are useful in detecting phenotypes of malignant lymphoma cells. Monoclonal antibodies such as LN1, LN2 and MB1 were applied for paraffin sections and those of B1, B4 and CALLA were used for frozen sections. The positivity of monoclonal antibodies used for paraffin sections were different according to cell types, small or large. Therefore, in order to obtain 100％ positivity for B cell type, it was necessary to use several combinations of monoclonal antibodies. On the other hand, frozen sections fixed with periodate-lysin-paraformaldehyde solution preserved antigenicity with anti-B1 (CD 20). It was interesting to observe several characteristics, that is, alkaline phosphatase reacting with mantle zone lymphoma as opposed to CALLA reacting with Burkitt's lymphoma. However, it will be necessary to further study to detect growth activity of lymphoma cells of the GI tract using Ki-67 or DNA-polymerase.