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.