Platelet count and T- and B-cell responses to GPIIb/IIIa during the course of IDEC-131/E6040 treatment in representative responders in the 10 mg/kg group. Platelet count, anti-GPIIb/IIIa antibody-producing B-cell frequency, GPIIb/IIIa-induced T-cell proliferation, and antigen-dependent anti-GPIIb/IIIa antibody production in PBMC cultures were evaluated at the indicated time points. Arrows denote the day of drug infusion (day 0). The lower panel shows representative images from the enzyme-linked immunospot assay for the detection of anti-GPIIb/IIIa antibody-producing B cells. Pre, pretreatment (day 0); 7P, 28P, 42P, and 56P, days 7, 28, 42, and 56 after treatment.