Deconstructing the liquid architecture of human herpesvirus 8 diseases.

Human herpesvirus 8 (HHV-8), also called Kaposi sarcoma herspesvirus (KSHV), causes several human tumours, which may be associated with systemic inflammation and body cavity effusions, including a form of multicentric Castleman disease (MCD) and a novel inflammatory syndrome, KSHV inflammatory cytokine syndrome (KICS). In this issue, Zhou et al. demonstrate that HHV-8-infected lambda-restricted plasmablasts can be detected in these effusions and can be used to distinguish MCD from other HHV-8 tumours as well as to categorise KICS into distinct clinicopathological groups. These findings open a path to an integrated clinicopathological approach to HHV-8-associated inflammatory diseases and may have clinical implications. Commentary on: Zhou et al. A novel approach for characterisation of KSHV-associated multicentric Castleman disease from effusions. Br J Haematol 2023;200:462-475.