Multicenter Prospective Study for Laboratory Diagnosis of HHV8 Infection in Solid Organ Donors and Transplant Recipients and Evaluation of the Clinical Impact After Transplantation

BACKGROUND: We performed serological and molecular pretransplant screening in solid organ transplant (SOT) donors and recipients in north-central Italy and a surveillance program for human herpes virus 8 (HHV8) infection after transplant, aiming to establish an optimal management of HHV8 infection in SOT recipients. METHODS: For pretransplant HHV8 screening in both donors and recipients, 6 serological (4 indirect immunofluorescent assays (IFA) and 2 enzyme-linked immunosorbent assays (ELISA) - both HHV8 lytic and latent antigen-based) and 2 molecular assays were used. A reference standard to identify HHV8-positive patients was defined by at least 2 positive assays. All transplant patients at risk to develop HHV8-related disease underwent virological posttransplant monitoring by quantitative real-time PCR assay. RESULTS: HHV8 seroprevalence was 4% (10/249) in donors and 18% (93/517) in organ recipients. The best performance was obtained by 2 lytic antigen-based IFAs that showed almost perfect agreement to the reference standard (0.943 and 0.931 Cohen’s kappa). HHV8-DNA was detected in 6.8% and 2.9% of HHV8-seropositive donor samples by in-house nested PCR and quantitative real-time PCR assays, respectively. After transplant, 3 out of 12 (25%) HHV8-mismatch patients (seropositive donor/seronegative recipient) developed a primary infection, 1 of whom developed a lethal nonmalignant illness. Two out of 93 HHV8-seropositive recipients (2.1%) had viral replication in posttransplant period, 1 of whom developed Kaposi’s sarcoma. CONCLUSIONS: Serological assays, specifically lytic IFAs, were the best methodological approach to identify HHV8-infected SOT donors and recipients. A very low incidence (1.9%) of posttransplant HHV8-related disease was observed.