Human herpesvirus 8 seroprevalence and viral load in healthy adult blood donors

BACKGROUND : Human herpesvirus 8 (HHV-8) is widely suspected to be a human tumor virus because it is associated with Kaposi's sarcoma and primary effusion B cell lymphoma. Report of a case of HHV-8-positive donor blood in the US has led to concern for the safety of donor blood from HHV-8-seropositive donors. STUDY DESIGN AND METHODS : The findings of HHV-8 seroprevalence and virus load from 100 randomly selected blood donors from the Houston, Texas, area are reported. Serology with serial titration was performed using a highly sensitive indirect immunofluorescence assay to lytic and latent HHV-8 antigens. For detection of blood-borne virus, buffy-coat DNA was subjected to two ultrasensitive nested PCR-dot blot assays to HHV-8 orf26 and orf72 regions. RESULTS : At a screening titer of 1 in 10, nearly one-quarter (23%; 95% CI, 15-33) of the blood donors are HHV-8 seropositive with a geometric mean titer of 1 in 53. Seroreactivity to lytic antigens (23%) greatly exceeded that to latent antigens (5%). There was a significant association between seropositivity and older age (p < 0.02), white ethnicity (OR, 3.33; 95% CI, 1.40-7.95) and ABO blood group B (OR, 6.44; 95% CI, 2.46-16.80). No association with sex or CMV seropositivity was demonstrated. No HHV-8 viremia was detected, even though 64 percent of tested donor blood samples were EBV DNA positive. CONCLUSIONS : Despite a relatively high HHV-8 seroprevalence in this cohort of Houston area blood donors, HHV-8 DNA was not detected in any sample of donor whole blood using a highly sensitive PCR assay. Thus, at least in the southeast Texas region, large-scale screening of blood donor units for HHV-8 antibody or DNA seems unwarranted.