To test this hypothesis, the investigators eventually intend to study the use of anti-retroviral therapies in patients with NHL. The investigators in vitro studies have demonstrated that HERV-K expression decreases in response to the currently FDA-approved and available, anti-HIV drugs, Lamivudine and tenofovir disoproxil fumarate (tenofovir). These medications are tolerated well in HIV patients, but it is unknown how the combination of Lamivudine and Tenofovir will be tolerated by patients with NHL. To further test the investigators hypotheses, the investigators propose the following Specific Aims of the current study: (1) To evaluate the tolerability, toxicity and safety of administering Lamivudine and Tenofovir in combination to patients with relapsed or refractory NHL; (2) To evaluate the effects of the combination of lamivudine and tenofovir on HERV-K plasma viral RNA load; and (3) To monitor the response rate of the NHL to treatment with the combination of lamivudine and tenofovir.