VWF MM ratio evaluation. (A) Exemplary VWF MM gel with plasma samples from patients with iTTP (lanes 2-11) and from a healthy control (lane 1). The densitometry trace below the stained gel represents lane 1 with its electrophoretic pattern divided in 4 zones according to the molecular weight: LMWM; IMWM; HMWM1; and HMWM2. The VWF MM ratio is defined as HMWM2/ LMWM. (B) Electrophoretic patterns and densitometry traces of 1 patient with iTTP in the course of the disease. Lane 3: in remission; lane 2: before acute bout; lane 1: in the acute bout before first TPE.