To evaluate the mechanism whereby thymopentin appears to retard the progressive immune suppression attributable to HIV infection.

Patients are randomized to receive subcutaneous thymopentin or placebo thrice weekly for 4 weeks.

Inclusion Criteria

Patients must have:

• Asymptomatic or minimally symptomatic HIV infection (no evidence of AIDS).
• CD4 count <= 400 cells/mm3 within 6 weeks prior to study entry (CD4 count changed to 100 - 400 cells/mm3 per amendment).
• Tolerated the current nucleoside analog antiretroviral treatment for at least 4 weeks prior to study entry.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms or conditions are excluded:

• Known hypersensitivity to thymopentin or any component of the formulation.
• Significant chronic underlying medical illness that would impede study participation.
• Grade 2 or higher peripheral neuropathy related to nucleoside analog antiretroviral treatment.

Concurrent Medication:

Excluded:

• Any antiretroviral agents other than zidovudine, didanosine, or dideoxycytidine.
• HIV vaccines or any investigational or non-FDA approved medication or immunomodulatory or experimental therapy within 30 days prior to study entry.

Patients with the following prior condition are excluded:

Abnormal chest x-ray consistent with active opportunistic infection within 6 weeks prior to study entry.

Prior Medication:

Excluded:

• Any prior antiretroviral agents other than zidovudine, didanosine, or dideoxycytidine within 30 days prior to study entry.

Required:

• Current nucleoside analog antiretroviral treatment.

Required:

• Nucleoside analog antiretroviral treatment for at least 4 weeks prior to study entry.

Significant active alcohol or drug abuse sufficient to prevent study compliance.