The objective of this double-blind placebo-controlled study is to evaluate the effect of Isoprinosine in a group of homogenous male volunteers who present with immunologic defects relative to:

• Comparison of total helper and suppressor T-cell number between the groups.
• Comparison of the phytohemagglutinins (PHA) and concanavalin A lymphoproliferative response and natural killer (NK) cell activity between the groups.
• Determination of the clinical course of the volunteers after discontinuance of Isoprinosine.

Exclusion Criteria

Co-existing Condition:

Patients with the following are excluded:

• Opportunistic infections or Kaposi's sarcoma.
• Critical illness.
• History of gout, urolithiasis, nephrolithiasis, renal dysfunction, and severe gastric ulcer.

Concurrent Medication:

Excluded:

• Steroids.
• Cytotoxic immunosuppressive agents.

Concurrent Treatment:

Excluded:

• Radiotherapy.

The following are excluded:

• Opportunistic infections or Kaposi's sarcoma.
• Critically ill patients.
• Patients receiving steroids, cytotoxic immunosuppressive agents, and/or radiotherapy.
• Patients who have received any other immunotherapy.
• Patients with a history of gout, urolithiasis, nephrolithiasis, renal dysfunction, and severe gastric ulcer.

Prior Medication:

Excluded:

• Any other immunotherapy.

Patients who fall into the group which is at risk of developing cutaneous sarcoma and/or opportunistic diseases but at present have no signs or symptoms of these diseases.