Quantitation of cell-free and cell-associated Kaposi's sarcoma-associated herpesvirus DNA by real-time PCR.

A real-time PCR assay for quantitation of Kaposi's sarcoma-associated herpes virus (KSHV or human herpesvirus 8) DNA was evaluated. The linear dynamic range was 10 to 10(5) copies of KSHV DNA (r(2) > 0.99). The accuracy of DNA purification and quantitation was less than +/-0.4 log(10) copies for samples that contained from 10 to 10(5) copies of KSHV DNA. Cell-associated KSHV DNA was quantitated over a range of infected cell frequencies from 0. 1 to 10(-5), and cell-free KSHV DNA in plasma was quantitated over a range of 100 to 10(6) copies/ml. Real-time PCR provides a convenient method for quantitation of cell-free and cell-associated KSHV DNA in laboratory and clinical specimens.