Journal of Clinical Microbiology, June 2000, p. 2174-2180, Vol. 38, No. 6
0095-1137/00/$04.00+0

Immunology Branch, Division of AIDS, STD, and TB Laboratory Research,1 and Viral Exanthems and Herpesvirus Branch, Division of Viral and Rickettsial Diseases,2 National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
Received 8 September 1999/Returned for modification 8 December 1999/Accepted 10 March 2000
A variety of assays for the diagnosis human herpesvirus 8 (HHV-8)
infection have been reported. We compared several such assays with
a panel of 88 specimens from human immunodeficiency virus (HIV)-infected patients with Kaposi's sarcoma (KS) (current-KS patients; n = 30), HIV-infected patients who later
developed KS (later-KS patients; n = 13), HIV-infected
patients without KS (no-KS patients; n = 25), and
healthy blood donors (n = 20). PCR assays were also
performed with purified peripheral blood mononuclear cells (PBMCs) to
confirm positive serologic test results. The order of sensitivity of
the serologic assays (most to least) in detecting HHV-8 infection in
current-KS patients was the mouse monoclonal antibody-enhanced
immunofluorescence assay (MIFA) for lytic antigen (97%), the
orfK8.1 peptide enzyme immunoassay (EIA) (87%), the orf65
peptide EIA (87%), MIFA for latent antigen (83%), the Advanced
Biotechnologies, Inc., EIA (80%), and the orf65 immunoblot assay
(80%). Combination of the results of the two peptide EIAs (combined
peptide EIAs) increased the sensitivity to 93%. For detection of
infection in later-KS patients, the MIFA for lytic antigen (100%), the
orfK8.1 peptide EIA (85%), and combined peptide EIAs (92%) were the
most sensitive. Smaller percentages of no-KS patients were found
to be positive (16 to 56%). Most positive specimens from the
current-KS and later-KS groups were positive by multiple assays, while
positive specimens from the no-KS group tended to be positive only by a
single assay. PCR with PBMCs for portions of the HHV-8 orf65 and gB
genes were positive for less than half of current-KS and later-KS
patients and even fewer of the no-KS patients. The concordance
between serologic assays was high. We propose screening by the combined
peptide EIAs. For specimens that test weakly positive, we
recommend that MIFA for lytic antigen be done. A positive result with a
titer of
1:40 would be called HHV-8 positive. A negative or low titer
would be called HHV-8 negative. If a population has a high
percentage of persons who test positive by the combined peptide EIAs,
then a MIFA could be performed with the negative
specimens to determine if any positive specimens are being missed.
Alternatively, if a population has a low percentage that test positive,
then a MIFA could be performed with a subset of the
negative specimens for the same reason. As described
above, only a titer of
1:40 would be considered HHV-8 positive.
Present address: National Institutes of Health, NCI/HAMB, Bethesda, Md.
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