Prednisone Active Not Recruiting Phase 2 Trials for AIDS-related Immunoblastic Large Cell Lymphoma / AIDS-related Peripheral/Systemic Lymphoma / Stage IV AIDS-related Lymphoma / AIDS-Related Diffuse Large Cell Lymphoma / AIDS-Related Diffuse Small Cleaved Cell Lymphoma / AIDS-related Small Noncleaved Cell Lymphoma / AIDS-Related Diffuse Mixed Cell Lymphoma / Stage III AIDS-related Lymphoma / AIDS-Related Lymphoblastic Lymphoma Treatment