IdeS treatment of thrombocytopenia is effective also when initiated at low platelet levels.

(A) Blood samples were taken at regular time intervals from three mice injected i.p. with a lethal dose of rabbit anti-mouse platelet IgG antibodies (1 mg IgG/mouse), and the number of platelets was determined by manual counting. (B) An additional ten mice were injected with the lethal dose of IgG. At three hours, five mice were treated i.v. with IdeS (0.5 mg in 0.25 ml PBS/mouse), while the other five received PBS alone (0.25 ml i.v/mouse). The PBS treated animals remained thrombocytopenic and died within 18–30 hours of IgG administration, whereas the IdeS treated animals all recovered their platelet levels and survived. These animals were sacrificed on day 14.