To determine the tolerance and side effects of a combination of lentinan and didanosine (ddI) in comparison with ddI alone. To determine whether the combination of lentinan and ddI produces a significant immunorestorative effect within the study observation period (6-12 months) as measured by an increase in one or more of the following: neutrophil count and activity, T-cell subsets, and a decrease in p24 antigen.

Patients are treated with daily oral ddI for 6 weeks, then are randomized to ddI in combination with intravenous lentinan or placebo (administered once weekly) for 26 weeks. Patients who are already stabilized on 400 mg/day ddI will proceed directly to randomization. Following completion of the combination therapy, patients may be offered 26 additional weeks of therapy on an optional basis.

Inclusion Criteria

Patients must have:

• HIV seropositivity.
• Absolute CD4 count of 200 - 500 cells/mm3.
• No active opportunistic infection or Kaposi's sarcoma.

Prior Medication:

Allowed:

• Prior ddI for no longer than 3 months.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms or conditions are excluded:

• Lymphoid malignancy.
• Pancreatitis.
• Peripheral neuropathy.
• Critical illness.

Concurrent Medication:

Excluded:

• Antiretroviral agents other than ddI.
• Steroids.
• Cytotoxic agents.
• Immunosuppressive agents.
• Immunomodulators.
• 1-Thyroxine.

Concurrent Treatment:

Excluded:

• Radiotherapy.

Prior Medication:

Excluded within 1 month prior to study entry:

• Antiretroviral agents other than ddI (patients may have received prior ddI for no longer than 3 months total).
• Steroids.
• Cytotoxic agents.
• Immunosuppressive agents.
• Immunomodulators.

Prior Treatment:

Excluded:

• Radiotherapy within 1 month prior to study entry. Active IV drug abuse.