Necrotizing lymphadenitis: a clinicopathological and immunohistochemical study of four familial cases and five recurrent cases.

We report the clinicopathological and immunohistological findings of nine cases of necrotizing lymphadenitis, consisting of four cases of familial infection and five cases of recurrence. Fever, cervical lymphadenopathy, leucopenia and swelling of the tonsils are characteristic clinical findings. Morphological features of the lymph nodes include the presence of immunoblasts, plasmacytoid T cells, histiocytes and macrophages, the latter with phagocytized nuclear debris derived from degenerated lymphocytes. However, granulocytes are generally absent. Ultrastructurally, tubuloreticular structures are observed not only in lymphoid cells, but in vascular endothelial cells. Immunological studies of peripheral blood using monoclonal antibodies disclose that CD 8+ (Leu 2a+; suppressor/cytotoxic) cells predominate at the onset, but they gradually decrease with the clinical course and the ratio of CD 4+: CD 8+ (helper:suppressor) increases as the disease progresses. However, in the affected lymph nodes, CD4+ (Leu 2a+: helper/inducer) cells often increase with the clinical progression, but the ratio of CD 4+:CD 8+ in the lymph nodes does not correlate with clinical progression. In addition, Ki-67+CD 8+ cells are more often seen than Ki-67+CD 4+ cells. It is suggested that necrotizing lymphadenitis is an infectious disease in which CD 4+ cells are disrupted and CD 8+ cells undergo transformation to blastoid cells. This results in a change in the ratio of T subsets.