Serologic screening and molecular surveillance of Kaposi sarcoma herpesvirus (KSHV)/human herpesvirus-8 (HHV-8) infections for early recognition and effective treatment of KSHV-associated inflammatory cytokine syndrome (KICS) in solid organ transplant recipients.

Kaposi sarcoma herpesvirus/human herpesvirus-8 (HHV-8) neoplastic and non-neoplastic disease in solid organ transplant (SOT) recipients can be life-threatening. We evaluated the seroprevalence of HHV-8 infection among donors (D) and recipients (R), the incidence of HHV-8 transmission/reactivation, and the clinical characteristics, management, and outcomes of HHV-8-related diseases, including Kaposi sarcoma herpesvirus-associated inflammatory cytokine syndrome (KICS), in consecutive SOT patients from 2011 to 2023. HHV-8 seroprevalence was 3.3% in 1349 donors and 8.4% in 1856 recipients screened (p<0.0001). Among the D+/R- group (n=49), 13 patients developed HHV-8-related diseases: 7 liver recipients had KICS, and 1 lung recipient had Kaposi sarcoma (KS) with subsequent KICS. Four KICS patients treated with rituximab survived, while the 3 patients not treated with rituximab died. Within the D-/R- group, out of 5 (0.3%) patients with non-donor-derived primary HHV-8 infection, 3 liver recipients developed KICS. In the R+ patients (n=155), 3 developed KS. In our cohort, 25/944 (2.6%) liver transplant recipients had a primary HHV-8 infection, and 10 of them (40%) developed KICS; 40% (4/10) of HHV-8 seropositive heart transplant recipients developed reactivation and 2 of them (50%) had fatal KS. Serologic screening and molecular surveillance of D+/R- patient groups facilitate early recognition and effective therapy of KICS.