To study the effectiveness of alpha interferon (IFN-A2b) and zidovudine (AZT) in treating progressive multifocal leukoencephalopathy (PML) as a complication of HIV-1 infection.

Inclusion Criteria

Patients must have:

• HIV seropositivity by both ELISA and Western blot.
• Biopsy proven progressive multifocal leukoencephalopathy (PML).

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• Intolerant to interferon.
• Prior or concomitant central nervous system disease (CNS) such as toxoplasmosis, multiple sclerosis (MS), or neurosyphilis.

Patients with the following are excluded:

• Intolerant to interferon.
• Prior or concomitant central nervous system disease (CNS) such as toxoplasmosis, multiple sclerosis (MS), or neurosyphilis.

Prior Medication:

Excluded:

• Patients receiving interferon for other reasons.