T-lymphocyte differentiation in vitro in primary immunodeficiency diseases

The effect of thymus extract on the development of cell surface antigenicity in two patients with primary immunodeficiency was studied and compared. A stem cell fraction from bone marrow preparations of a patient with severe combined immunodeficiency failed to develop cells with antigenic markers of T-lymphocytes while that of a patient with common variable form of immunodeficiency who had both severe functional deficits of T-lymphocytes and agammaglobulinemia developed cells with such markers after treatment with thymus extract. These findings indicate that the two forms of severe combined immunodeficiency disease studied have different bases which may be reflected in differences of response to differentiative influence of thymus extract.