Immunodeficiency diseases. I. T-lymphocyte precursors and T-lymphocyte differentiation in partial Di George syndrome.

Immunological and pathological studies in a case of partial Di George syndrome revealed an absence of parathyroids, a major hypoplasia of thymus but a relatively moderate decrease in peripheral T-lymphocyte numbers and functions. After in vitro incubation with normal thymus extracts, a normal proportion of bone marrow cells was induced to differentiate into cells with characteristics of T lymphocytes, thus establishing the presence of T-cell precursors in the patient's bone marrow.