- Have a history of opportunistic infections and cancers (Mycobacterium avium complex, cytomegalovirus, toxoplasmic encephalitis or disseminated toxoplasmosis, cryptosporidiosis, Isospora belli, progressive multifocal leukoencephalopathy, visceral Kaposi's sarcoma, and lymphoma). Patients with past episode of pulmonary tuberculosis, Pneumocystis carinii pneumonia, or isolated cutaneous Kaposi's sarcoma are allowed. Medication for the prevention of PCP (TMP/SMX, nebulized pentamidine, and atovaquone) is allowed.