 In patients with chronic HIV infection, HIV replication and abnormalities in immune function persist following treatment with highly active antiretroviral therapy HAART. Specifically, costimulatory T cell interactions are impaired. The immune modulatory drug thalidomide was recently found to costimulate T cells. Pharmacologic T cell costimulation may compensate for the T cell deficiencies in people with HIV disease and improve immune function. This study will test whether thalidomide treatment enhances HIV and cytomegalovirus CMV-specific immunity in patients with HIV and CMV, and will evaluate the effect of thalidomide on HIV replication. 