Fig. 3
Scatchard plots of insulin antibody in this patient. Before treatment of double filtration plasmapheresis and prednisolone (circle, k1 = 0.0032 × 108 M−1, R1 = 112 × 10−8 M) and after treatment (triangle, k1 = 0.0400 × 108 M−1, R1 = 9.1 × 10−8 M). Bound/free insulin at low concentration of bound insulin is thought to reflect the degree of affinity of the antibody. To assess the quantity of high-affinity antibody in relation to the level of affinity, the authors calculated the value of X intercept (R1) multiplied by the Y intercept (k1R1) of the Scatchard line for high-affinity binding sites, where k1 and R1 were affinity constant and binding capacity in high-affinity binding sites, respectively. These plots of after treatment indicate the degree of affinity of the antibody increased, whereas the degree of binding capacity dramatically decreased compared with before treatment