Background: HIV infection is associated with a marked increase in risk for non-Hodgkin lymphoma (AIDS-NHL). However, the mechanisms that promote the development of AIDS-NHL are not fully understood. Methods: In this study serum levels of several cytokines and other molecules associated with immune activation were measured in specimens collected longitudinally during 1-to-5 years preceding AIDS-NHL diagnosis, in 176 AIDS-NHL cases and 176 HIV+ controls from the Multicenter AIDS Cohort Study (MACS). Results: Multivariate analyses revealed that serum levels of immunoglobulin free light chains (FLC), IL-6, IL-10, IP-10/CXCL10, neopterin, and TNFα were elevated in those HIV+ individuals who went on to develop AIDS-NHL. Additionally, the fraction of specimens with detectable IL-2 was increased, and the fraction with detectable IL-4 was decreased, in these subjects. Conclusions: These results suggest that long term, chronic immune activation, possibly driven by macrophage-produced cytokines, precedes development of NHL in HIV+ individuals. Impact: FLC, IL-6, IL-10, IP-10/CXCL10, neopterin, and TNFα may serve as biomarkers for AIDS-NHL.

Human herpesvirus 8 (HHV-8) is the etiological agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. It is postulated that CD8؉ T cell responses play an important role in controlling HHV-8 infection and preventing development of disease. In this study, we investigated monofunctional and polyfunctional CD8 ؉ T cell responses to HHV-8 lytic proteins gB (glycoprotein B) and K8.1 and latency proteins LANA-1 (latency-associated nuclear antigen-1) and K12. On the basis of our previous findings that dendritic cells (DC) reveal major histocompatibility complex (MHC) class I epitopes in gB, we used a DC-based system to identify 2 novel epitopes in gB, 2 in K8.1, 5 in LANA-1, and 1 in K12. These new HHV-8 epitopes activated monofunctional and polyfunctional CD8 ؉ T cells that produced various combinations of gamma interferon, interleukin 2, tumor necrosis factor alpha, macrophage inhibitory protein 1␤, and cytotoxic degranulation marker CD107a in healthy HHV-8-seropositive individuals. We were also able to detect HHV-8-specific CD8 ؉ T cells in peripheral blood samples using HLA A*0201 pentamer complexes for one gB epitope, one K8.1 epitope, two LANA-1 epitopes, and one K12 epitope. These immunogenic regions of viral lytic and latency proteins could be important in T cell control of HHV-8 infection.