Distribution of human herpesvirus 8 DNA in tumorous and nontumorous tissue of patients with acquired immunodeficiency syndrome with and without Kaposi's sarcoma.

Human herpesvirus 8 (HHV-8) DNA is present in virtually all Kaposi's sarcomas (KSs). Conflicting results, however, exist with respect to the presence of HHV-8 in nontumorous tissue samples. To define the specificity and predictive value of HHV-8 DNA detection in KS, we analyzed autopsy-derived tissue samples from patients with acquired immunodeficiency syndrome (AIDS) with and without KS for the presence of HHV-8 DNA, using single-step and nested polymerase chain reaction. Semiquantitative analysis of HHV-8 DNA was performed by endpoint dilution assays. HHV-8 DNA was detected in 41 (100%) tumor tissue samples of KSs. According to nested polymerase chain reaction results, HHV-8 DNA was also present in 16 (32%) of 50 nontumorous specimens of patients with AIDS patients with KS and in 3 (2.7%) of 113 specimens of patients with AIDS without KS; it was absent in 26 autopsy tissues and 15 transurethral resected prostatic specimens of patients without AIDS. By use of a second, unrelated primer set, the presence of HHV-8 DNA was confirmed in 12 (63.2%) of 19 nontumorous samples and detected in another 6 (17.7%) of 34 samples tested. Significantly higher titers of HHV-8 DNA were found in tumorous than in nontumorous tissues samples (1.9 x 10(4) vs. 1.2 x 10(2); P < .05). Specificity and positive predictive values for the diagnosis of KS by detecting HHV-8 DNA in a given tissue sample were 56 and 65.1% in patients with manifest KS and 97.4 and 100% in patients without previously known KS. An increased specificity and a positive predictive value were observed when the presence of KS anywhere in a given patient was considered (92.9 and 77.8%, respectively). In conclusion, the detection of HHV-8 DNA is a sensitive test for the diagnosis of KS. Its specificity, however, might be lower because HHV-8 can be detected in histologically unaffected tissue of patients with KS.