Immunohistological analysis of malignant lymphomas of B cell origin

Lymph node biopsies from 39 patients with malignant lymphoma primary in lymph node were examined by the peroxidase-antiperoxidase (PAP) method at the light microscopical level and by the electron microscopical enzyme-labeled antibody (EMELA) method at the subcellular level in order to clarify the nature of immunoglobulin production in malignant lymphoma. As the results, out of the 39 cases of the present series, localization of cytoplasmic immunoglobulins in neoplastic cells was demonstrated in 20 cases with the PAP method and in 28 with the EMELA method, and out of the 28 cases in which localization of cytoplasmic immunoglobulins was verified at the subcellular level, a positive reaction against anti-IgM antiserum was found in 25 cases. From these findings, it is concluded that the immunoglobulin-producing malignant lymphoma primary in lymph node is an IgM-producing neoplasm with a few exceptional cases such as gamma-chain disease, in sharp contrast with the fact that IgG or IgA-producing tumors predominated in plasmocytomas primary in bone marrow. Based on the cytological characteristics of the neoplastic cells and localization of cytoplasmic immunoglobulins, B-cell lymphomas were classified into several types according to their maturation stages and were applied to maturation processes of B-lymphocytes recently being accepted.