Lymphocytic lymphoma/B-chronic lymphocytic leukaemia--an immunohistopathological study of peripheral B lymphocyte neoplasia.

Twenty seven patients with malignant lymphoma of lymphocytic type/B-chronic lymphocytic leukaemia (ML, L/B-CLL, Kiel classification) diagnosed from lymph node and splenectomy specimens were studied histologically and immunologically. Lymph node biopsies showed a diffuse effacement of normal architecture by small round lymphocytes usually with scattered proliferation centres (PC). A1 spleens showed white pulp with or without red pulp involvement, sometimes with tumour nodules present. PC-like cells or PC were only found in the white pulp or tumour nodules. Studies of 13 specimens using the ABC immunoperoxidase technique on frozen sections with a large panel of monoclonal antibodies showed that although a part of the monoclonal B cell neoplasm, the proliferation centres or splenic white pulp have a different phenotype from the surrounding cells. Some of these phenotypic changes are similar to those reported with in vitro induction of "maturation" of ML, L/B-CLL cells. The implications for normal B-cell development are discussed. In contrast to reported peripheral blood findings, T cells, predominantly of T helper phenotype in lymph nodes, were present but usually not numerous.