Immunologic characterization of human malignant lymphomas

Abstract

The immunologic and morphological approach of our recently proposed functional classification of malignant lymphomas based on the T and B cell systems and lymphocyte transformation has been reviewed. Preliminary results of our retrospective morphological studies indicate: 1) Over 70% of non-Hodgkin's lymphomas involve cleaved or noncleaved follicular center cell (FCC) or B cell types. 2) Nodularity is observed only with FCC types and suggest origin in follicular centers as a block or a “switch on” (derepression) in B cell lymphocyte transformation. 3) Lymphomas of “true” histiocytes appear rare and need to be redefined with functional studies since those previously regarded as histiocytic are indistinguishable morphologically from transformed lymphocytes. 4) Lymphomas of large transformed lymphocytes, “immunoblastic sarcoma” of B and T cell types, have been observed to develop in abnormal immune states and senescence and represent a distinctive entity. Ideal characterization of lymphomas using integrated morphological, cytochemical, and immunologic membrane marker studies has been outlined, and preliminary results of this approach provide support for our new proposal.