Immunohistologic studies of Kikuchi's disease.

An immunohistologic study of lymph nodes from 21 patients with Kikuchi's disease (histiocytic necrotizing lymphadenitis) was performed. The cell components of the affected areas were mainly CD4-positive cells, CD8-positive T cells, alpha/beta T-cell gene receptor-positive T cells, and lysozyme-staining cells. CD3-positive or alpha/beta T-cell gene receptor-positive T cells were composed mainly of CD8-positive and CD11b-negative cytotoxic T cells. Double staining demonstrated that CD4-positive cells usually were positive for Ki-M1p, a marker of plasmacytoid monocytes, but negative for T-cell markers. Although some lysozyme and CD4 double-positive cells were recognized, most CD4-positive cells were negative for lysozyme. The results indicate that CD4-positive cells in the affected foci of Kikuchi's disease were mainly composed of plasmacytoid monocytes.