VANCOUVER, BC--The discovery in 1994 of a new human herpesvirus
associated with Kaposi's sarcoma (KS) brought some order to the
previously contentious discussion about causes of the disease
in patients with HIV. Researchers at the 11th International Conference
on AIDS further nailed human herpesvirus-8 (HHV-8, also known
as Kaposi's sarcoma-associated herpesvirus or KSHV) as the culprit
in many, if not most, cases of KS (see also, page 1).
Antibodies against HHV-8 appear in more than three quarters of
patients with AIDS prior to the appearance of KS, said Shou-Jiang
Gao, PhD. Dr. Gao and colleagues in New York, Pittsburgh, Baltimore,
Chicago, Los Angeles, and Atlanta developed a Western blot assay
to detect antibodies to two latent nuclear antigens of HHV-8.
This assay was then used to look for anti-HHV-8 antibodies in
serum samples from 40 patients with AIDS and KS. Samples had been
drawn an average of 47 months before KS onset.
Antibodies were found in sera of 31 of 40 patients with KS (77.5%)
versus 7 of 40 AIDS patients who did not have KS (17.5%) and none
of 122 general population blood donors.
David Blackbourn, PhD, and associates in San Francisco and Portland
showed that the novel herpesvirus-like DNA sequences detected
in KS belong to an infectious agent. They found that filtered
fluids from HHV-8-infected peripheral blood mononuclear cells
(PBMCs) or from PBMCs co-cultured with KS tumor samples could
spread the infection to cultured human CD19+ B cells and endothelial
Peter Biberfeld, MD, and colleagues at Karolinska Hospital, Stockholm,
found that not only AIDS-associated KS but also endemic KS appears
consistently associated with HHV-8 DNA irrespective of stage,
tissue, gender, or age. This study included Swedish HIV patients
with KS and Tanzanian patients with endemic KS.
Yao-Qi Huang, PhD, and colleagues in New York and Dallas found
that HHV-8 can be detected in the organs where KS most often occurs,
including the lymph nodes, lung, stomach, spleen, prostate, esophagus,
Dr. Huang studied autopsy specimens from five AIDS patients with
KS and six AIDS patients without KS. HHV-8 DNA sequences were
identified with the polymerase chain reaction. HHV-8 was pres-ent
in all of the patients with KS, most often in the lung, stomach,
prostate, and rectum. HHV-8 was not found in any of 50 samples
from non-KS patients.