Relationship of plasma levels of FXII to those of TTR in IL-2–treated patients. Data were those obtained in 7 cycles of escalating doses of rIL-2 administered to 4 patients. In each patient, initial levels of FXII and TTR were arbitrally set at 1 and protein levels at subsequent days were related to these. Data points represent the relative concentrations measured in plasma samples that were taken daily (r = .76, P < .0001).