An unusual case of immunoblastic lymphadenopathy (IBL) with circulating CD3-CD4+ cells is reported. A lymph node biopsy specimen showed the characteristic features of IBL. Two-color analyses demonstrated that the circulating abnormal cells were CD3-, CD4+, HLA-DR+, and CD25-. Chromosomal analysis revealed unrelated clones in the lymph node. Though 48% of the peripheral blood lymphocytes were abnormal, no clonal rearrangement of the TcR beta chain gene was detected in the peripheral blood. This case might point out the possibility that some cases of IBL truly had no TcR gene rearrangement and were dysplasias.
To study the pathogenesis of multicentric Castleman's disease (MCD), IL-6 producing cells and immune function were investigated in four MCD patients. The expression of IL-6 mRNA in one MCD lymph node was analysed by in situ hybridization. IL-6 mRNA expressing cells were scattered in the interfollicular areas and did not resemble plasma cells. Spontaneous IL-6 production was detected in the culture supernatants of peripheral blood mononuclear cells (PBMNC) from four patients. The IL-6 producing cells among the PBMNC were found to be monocytes by both in situ hybridization and immunohistochemistry. We evaluated immune function in four MCD patients. These studies show: (1) a negative PPD skin test in 3/4 patients, (2) decreased IL-2 production in 3/4 patients, (3) decreased T cell colony formation in 3/4 patients, (4) decreased NK activity and NK cell number in 2/4 patients, (5) increased soluble IL-2 receptor in 4/4 patients, and (6) decreased CD4/CD8 ratio in 3/4 patients. These results show that MCD resembles, in several ways, acquired immunodeficiency syndrome (AIDS).