Prednisone Recruiting Phase 1 Trials for CD20 Negative / Ann Arbor Stage II Diffuse Large B-Cell Lymphoma / HIV Positivity / Stage II Diffuse Large B-Cell Lymphoma / Stage III Diffuse Large B-Cell Lymphoma / Stage IV Diffuse Large B-Cell Lymphoma / Ann Arbor Stage IV Diffuse Large B-Cell Lymphoma / Ann Arbor Stage III Diffuse Large B-Cell Lymphoma / CD20 Positive / Lymphoma, AIDS Related / Human Immunodeficiency Virus Positive Treatment