NECROTIZING LYMPHADENITIS Electron Microscopical and Immunohistochemical Study

Seven cases of necrotizing lymphadenitis (NEL) including a pair of male siblings, a female suffering from non-bacterial meningitis, and two cases with the proliferation of monocytes and/or macrophages in the bone marrow are reported. This disease is clinically documented by the occurrence in young adults usually accompanied by painful cervical lymphadenopathy with fever and leukopenia (below 4,000/mm3). Morphological features were characterized by nuclear debris from degenerated lymphocytes and the appearance of blastoid cells and/or immunoblasts and macrophages. Ultrastructurally, tubular Inclusions with a close relation to the endoplasmic reticulum were observed in various kinds of cells in the lesion. Immunohistochemical studies revealed that the ratio of helper/suppressor T-lymphocytes became low at the active stage and returned to normal range at the recovery stage. By immunohistochemical study it was confirmed that suppressor cells mainly corresponded to large transformed lymphocytes and/or immunoblasts and helper cells were degenerated by an unknown agent. Though the pathogenesis of NEL is still uncertain, it is suggested that T-lymphocytes are mainly involved during the course of the disease and lymphocytes show cellular debris or blastoid transformation. ACTA PATHOL. JPN. 37:1071–1084, 1987.