Circulating T-cell numbers and patient proliferation responses to mitogen and antigen over time.

(A) CD3⁺ T cells in the circulation of patient 1 (■) and patient 2 (○). (B-D) Stimulation index (SI) defined as counts per minute in wells treated with mitogen or antigen divided by counts per minute of media alone. SI of patient 1 (■) and patient 2 (○) to PHA (B), tetanus (C), and diphtheria (D). The shaded area marked by × symbols indicates the normal range of CD3⁺ T cells, mitogen, and antigens along the y-axis.