Abstract

The thymus gland, which plays a key role in the maturation and functioning of the lymphoid system, is implicated in the acquired immune deficiency syndrome (AIDS). The observation that the thymic hormone, thymosin α1, is elevated in individuals at risk for AIDS (as opposed to being depressed in other immunodeficient states) has provided the first direct evidence that the thymus is malfunctioning early in the course of this deadly disease. These observations have been valuable in screening for the syndrome with a rapid radioimmunoassay and in the initiation of the first clinical trials with thymosin in high risk homosexuals and hemophiliacs. If the progressive immune paralysis in AIDS is due to a dying thymus, the early identification of asymptomatic carriers of AIDS or individuals with modest AIDS‐related dysfunction may lead to therapy with thymosin or other thymomimetic agents that can restore immune function and prevent the onset of frank AIDS.