In this study we report on the establishment and characterization of two novel lymphoma cell lines (CRO-AP/3 and CRO-AP/5) which carry infection by human herpesvirus type-8 (HHV-8) and have derived from AIDS-related primary effusion lymphoma (PEL). These two cell lines are representative of different virologic subtypes of PEL, i.e. HHV-8+/EBV- PEL in the case of CRO-AP/3 and HHV-8+/EBV+ PEL in the case of CRO-AP/5. Consistent with the diagnosis of PEL, both CRO-AP/3 and CRO-AP/5 expressed indeterminate (i.e. non-B, non-T) phenotypes although immunogenotypic studies documented their B-cell origin. Both cell lines are devoid of genetic lesions of c-MYC, BCL-2 and p53 as well as gross rearrangements of BCL-6. Detailed histogenetic characterization of these novel PEL cell lines suggests that PEL may derive from a post-germinal centre B cell which has undergone pre-terminal differentiation. The CRO-AP/3 and CRO-AP/5 cell lines may provide a valuable model for clarifying the pathogenesis of PEL. In particular, these cell lines may help understand the relative contribution of HHV-8 and EBV to PEL growth and development and may facilitate the identification of recurrent cytogenetic abnormalities highlighting putative novel cancer related loci relevant to PEL.