- Patients with known history of testing positive for human immunodeficiency virus (HIV) or known acquired immunodeficiency syndrome (AIDS) might be enrolled if the viral load by polymerase chain reaction (PCR) is undetectable with/without active treatment and absolute lymphocyte count >= 350/ul; patients with a known positive test for hepatitis B virus surface antigen (HBV sAg) or hepatitis C virus ribonucleic acid (HCV antibody) indicating acute or chronic infection might be enrolled if the viral load by PCR is undetectable with/without active treatment