Characterization of ζ-associated protein, 70 kd (ZAP70)-deficient human lymphocytes

We show that in the absence of ZAP70, thymopoiesis is altered and differentiation to double-positive cells is hampered. Circulating T cells appear poorly regulated, do not differentiate into TH2 T cells, lack a number of inhibitory growth controls, and display reduced apoptosis, all predisposing patients to exaggerated inflammation and autoimmunity.