Angioimmunoblastic lymphadenopathy with disseminated human herpesvirus 6 infection in a patient with acute myeloblastic leukemia.

A 47-year-old man with acute myeloblastic leukemia (AML) developed angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) 4 months after induction chemotherapy for AML. During a leukopenic period, the patient suffered from pericarditis with massive pericardial effusion in which human herpesvirus 6 (HHV-6) DNA was detected. Although complete remission of AML was achieved, fever persisted and atypical skin rash followed by generalized lymphadenopathy along with polyclonal hypergammaglobulinemia appeared. A diagnosis of AILD was made on a biopsy specimen of the inguinal lymph node. The patient died of fulminant hepatitis and the autopsy showed lymphomatous infiltrates involving the liver, bone marrow, lungs, spleen, kidneys and heart. HHV-6 DNA sequences were identified in the biopsy specimen of the lymph node and in the involved organ tissues. HHV-6 in this patient was variant B. It is known that HHV-6 can be reactivated in immunocompromised patients and causes severe complications. This unusual clinical course suggests that the immunosuppression associated with AML and the additional iatrogenic immunosuppression following cytopenia-inducing chemotherapy predisposed the patient to reactivated HHV-6 infection. The sequential detection of this virus before and after manifestation of AILD may support the evidence that HHV-6 infection could directly or indirectly trigger AILD. This is the first time that such a sequence of events has been reported to our knowledge. The possibility of HHV-6 infection should be considered when unexplained fever and generalized lymphadenopathy are seen in patients with leukemia, and administration of antiviral agents should be considered for the diagnostic evaluation.

Establishment and characterization of a thymic carcinoma cell line (Ty-82) carrying t(15;19)(q15;p13) chromosome abnormality.

A new human cell line, designated Ty-82, was established from the pleural effusion of a 22-year-old woman with undifferentiated thymic carcinoma. This cell line consisted of primitive cells that were positive for alpha-naphthyl butyrate esterase and acid phosphatase. The cells were shown to express epithelial membrane antigen, but were completely negative for cytokeratin, carcinoembryonic antigen, glial fibrillary acidic protein, desmin, S-100 protein, lysozyme, Leu-7, HLA-DR (Ia), leukocyte common antigen, Ki-I antigen, T-cell antigens, B-cell antigens, myelomonocyte antigens, and Epstein-Barr-virus nuclear antigen. Electron microscopy showed that the cells were highly anaplastic, with no sign of cellular differentiation to any lineages. The Ty-82 cell line was found to have a karyotype of 46,XX,t(15;19)(q15;p13), being identical to that of the patient's tumor cells. Four of 5 nude mice inoculated sub-cutaneously with Ty-82 cells developed tumors which displayed a histological picture similar to the original tumor. Thymic carcinoma is a recently recognized entity, and its cellular and clinical behavior are poorly understood. The newly established thymic carcinoma cell line would provide a useful tool for the better understanding of this rare disease.