The study will last 18 weeks. Participants will receive weekly injections of 180 mcg PEG-IFN alfa-2a at the clinic for 12 weeks. After Week 12, participants will be followed off-treatment until Week 18. Physical exams will be performed weekly. Blood collection to monitor viral load, PEG-IFN alfa-2a serum levels, and CD4 and CD8 counts will be conducted at selected weeks during the study. Filgrastim will be given to patients who exhibit neutropenic toxicity.