The thymus obtained at autopsy from two patients with severe combined immunodeficiency disease (SCID) were placed in culture to establish epithelial monolayers. These thymic epithelial monolayers and their supernatants were tested for their inductive influence on marrow cells from normal donors and, in addition, one monolayer was tested for its capacity to induce differentiation on marrow cells from another patient with SCID. The first thymic epithelial monolayer (B.H.) induced E-rosetting markers and mitogen responses in normal marrow cells but not in the marrow cells of the patient with SCID. These same SCID marrow cells were partially differentiated to E rosettes but responses to phytomitogens were not induced when these marrow cells were cultured on normal thymic epithelial monolayers. The epithelial monolayers from the second SCID patient (D.V.) induced the E-rosette markers but not HTLA markers on normal marrow cells. Evaluation of serum thymic hormone levels in patient D.V. had previously revealed absence of thymopoietin and low normal values of serum facteur thymique serique. These findings suggest that in SCID, a defect of the thymus may exist at the initial step of processing of cells which may be a prerequisite for subsequent differentiation events in the cell development. This defect appears to be related to impaired secretory activity for one or possibly more thymic hormones and seems to represent a functional defect of the thymic stroma.
ASJC Scopus subject areas
- Immunology and Allergy
- Pathology and Forensic Medicine