1. Study Design UIHC HIV Clinic Patients Invitation – Informed Consent Heparinized Blood/Serum Obtained CD4, HIV VL measured Serum => GBV-C VL Cells => flow cytometry Does GBV-C alter B cell & NK cell activation or alter monocyte CCR5/CXCR4 expression? GBV-C blunts T cell activation & proliferation GBV-C induces chemokines GBV-C CCR5 and CXCR4 on CD4 cells GBV-C replicates in T and B cells P=0.01 N=11N=13N=11N=9 ns

2. P=0.018 P=0.009 B cell activation: GB+ < GB- p=0.024 HIV Viremic GB+ < GB- p=0.018 NK cell activation: CD56dim/CD16+: NS CD56brt/CD16-: If HIV RNA neg: NS If HIV RNA pos: GB+ < GB- p=0.009

3. Monocyte CCR5 expression GB+ < GB- p=0.009 HIV RNA+: GB+ < GB- p=0.03 CXCR4 GB+< GB-, but NS P=0.03 Conclusion: GBV-C replication in vivo Diminishes B cell activation Blunts CD16+ NK cell activation Downregulates monocyte CCR5 GBV-C replicates in T and B cells; however, replication limited to a very small percentage of cells. Replication has not been shown in NK cells or monocytes. Effect in these cells may be due to induction of chemokines and/or cytokines The effect of GBV-C activation on T and B lymphocytes, NK cells and monocytes may contribute to prolonged survival in HIV- infected individuals.