Inclusion Criteria

Concurrent Medication:

Allowed:

• Maintenance therapy for opportunistic infection, provided patient has received at least 1 month of stable therapy prior to study.
• G-CSF.

Patients must have:

• HIV infection.
• CD4 count <= 500 cells/mm3.
• At least 12 months of prior AZT, with 2 months of continuous AZT monotherapy immediately prior to study.
• The need to discontinue AZT because of drug-related toxicity or unwanted side effects or as an entry requirement for another research study.
• Consent of parent or guardian if < 18 years old.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms or conditions are excluded:

• Current medical status that is considered unsuitable for study participation.

Concurrent Medication:

Excluded:

• Therapy for an acute opportunistic infection.

Prior Medication:

Excluded within the past 2 months:

• Antiretrovirals other than AZT.
• Systemic immunomodulators (e.g., gp120, gp160, IL-2, and interferons).

Excluded within the past month:

• Vaccination.