Inclusion Criteria:

• HIV infected
• CD4 count of 300 cells/ml or greater within 30 days of study entry
• HIV viral load of 5000 copies/ml or greater within 30 days of study entry
• Received ART previously but have currently interrupted treatment within 12 weeks prior to study entry OR ART naive
• Willing to delay initiation or re-initiation of antiretroviral medications for the duration of the study
• Agree to use acceptable forms of contraception

Exclusion Criteria:

• Previous use of interferon alfa
• Known allergy or sensitivity to PEG-IFN alfa-2a or its formulation
• Active drug or alcohol abuse that would interfere with the study
• Acute therapy for a serious infection within 30 days of study entry
• Use of non-protocol-specified immunomodulatory therapy within 60 days of study entry
• Active immunization within 30 days of study entry
• History of severe psychiatric disease such as major depression, suicidal attempt, hospitalization for psychiatric disease, or a period of disability due to psychiatric disease
• History of poorly controlled thyroid disease, including history of elevated thyroid stimulating hormone (TSH) levels with elevated antibodies to thyroid peroxidase and any clinical manifestations of thyroid disease
• History of clinically significant heart disease that could be worsened by acute anemia
• History of severe seizure disorder or current anticonvulsant use
• Hepatitis C antibody positive within 60 days prior to study entry
• Hepatitis B surface antigen positive within 60 days prior to study entry
• Known sensitivity to E. coli derived products, such as filgrastim
• Any past evidence of chronic liver disease
• Any past or current evidence of immunologically-mediated disease
• Evidence of chronic pulmonary disease
• Severe eye problems due to diabetes, hypertension, cytomegalovirus infection, or macular degeneration
• History of major organ transplantation with an existing functional graft
• History or other evidence of severe illness, cancer, or other conditions that would make the patient unsuitable for the study
• Hemoglobin abnormalities or any other cause of or tendency for breakdown of red blood cells
• Any medical condition that would prevent successful completion of the study
• Use of certain medications
• Pregnant or breastfeeding