T-cell development as determined by T-cell subset antibody staining and T-cell proliferative responses to mitogens for subjects past 1 year after thymus transplantation. Fourteen subjects who did not receive immunosuppression (A-C,G) are compared with 12 subjects who did receive immunosuppression (D-F,H); (A,D) CD3, (B,E) CD4, (C,F) CD8, (G,H) PHA responses. Each subject is represented by a separate line. The x-axis is years after transplantation. The y-axis for panels A to F is cells/mm³. The y-axis for panels G and H is counts per minute. Note the T-cell amplifications seen in panels A to C for 4 subjects who developed the atypical form of DiGeorge anomaly shortly after transplantation.