Hideki Ohminami

APOPTOSIS OF CD4+ T LYMPHOCYTES IN HUMAN HERPESVIRUS-6 INFECTION

The present authors have recently reported that inoculation with human herpesvirus-6 (HHV-6) renders CD4+ T lymphocytes susceptible to apoptosis in vitro. In order to confirm that apoptosis of CD4+ T lymphocytes also occurs in HHV-6 infection in vivo, apoptosis of lymphocytes isolated from nine patients with exanthem subitum and from an adult patient with severe HHV-6 infection was examined. Peripheral blood mononuclear cells were cultured for 3 days and apoptosis of lymphocytes was then examined by flow cytometry of propidium iodide-stained DNA. The percentages of hypodiploid DNA, indicating apoptosis, in lymphocytes from 10 patients with HHV-6 infection were significantly higher than those from five infant patients with noninfectious diseases and five healthy adults (P < 0-0002). DNA fragmentation was also detected by agarose gel electrophoresis in lymphocytes from patients with HHV-6 infection. Apoptosis appeared to occur predominantly in CD4+ T lymphocytes and HHV-6 was isolated from the CD4+ T lymphocyte fraction. These data demonstrate that HHV-6 renders CD4+ T lymphocytes susceptible to apoptosis in vivo.

Neoplastic involvement of granulocytic lineage, not granulocytic-monocytic, monocytic, or erythrocytic lineage, in a patient with chronic neutrophilic leukemia case report

Chronic neutrophilic leukemia (CNL) is a very rare myeloproliferative disorder. To determine the neoplastic origin of CNL, morphological and cytogenetical studies were made of colonies derived from hematopoietic progenitors of a patient with CNL. The patients hematopoietic progenitors spontaneously formed colonies consisting of mature granulocytes, and cytogenetical study of the colonies indicated chromosome abnormalities identical to those in the patients bone marrow cells. Analysis of colonies consisting of granulocytes and macrophages, macrophages, or erythrocytes disclosed a normal karyotype. These results demonstrated that the neoplastic process in this patient with CNL originated in hematopoietic progenitors capable of differentiating only into granulocytes, and not granulocytes and monocytes, monocytes, or erythrocytes. Am. J. Hematol. 57:221–224, 1998.