Acquired immunodeficiency syndrome.

A retrovirus designated HTLV-III has been recovered from patients with AIDS and patients with pre-AIDS syndrome. This virus, which appears to be the cause of AIDS, attacks and suppresses T-helper lymphocytes, rendering the host susceptible to a variety of serious protozoal, fungal, mycobacterial, bacterial and viral infections, as well as neoplasms. Pneumocystis carinii and cytomegalovirus are frequent causes of pulmonary infiltrates in AIDS.