Unraveling virus-induced lymphomagenesis.

Kaposi sarcoma herpesvirus (KSHV), a human gammaherpesvirus, is the etiological agent for the endothelial-derived Kaposi sarcoma (KS) and also for certain lymphoproliferative disorders. In these lymphoproliferations, the KSHV-infected cells carry the stigmata of B lymphocytes, with plasmablastic features. The JCI has published three manuscripts addressing key questions related to B cell infection and viral latent expression in B cells. Myoung and Ganem provide evidence that CD4(+) lymphocytes suppress KSHV replication, promoting latency in B cells; Hassman and colleagues show that KSHV infection drives plasmablast differentiation in a subset of IgM(+) λ light chain-expressing cells; and Ballon and colleagues describe the in vivo transdifferentiation of B lymphocytes by KSHV-encoded viral FLICE-inhibitory protein (vFLIP).