Disclosed is the use of a MASP-2 inhibitory agent which inhibits MASP-2-dependent complement activation in the manufacture of a medicament for treating a subject suffering from thrombotic thrombocytopenic purpura (TTP), or exhibiting symptoms consistent with a diagnosis of TTP, wherein the medicament is formulated for administration to the subject via an intravenous catheter or other catheter delivery method, wherein the MASP-2 inhibitory agent is an anti-MASP-2 antibody or fragment thereof, and wherein the subject exhibits at least one or more symptoms selected from the group consisting of central nervous system involvement, thrombocytopenia, severe cardiac involvement, severe pulmonary involvement,, gastro-intestinal infarction and gangrene. Also disclosed is the use of a MASP-2 inhibitory agent which inhibits MASP-2-dependent complement activation in the manufacture of a medicament for treating a subject suffering from refractory thrombotic thrombocytopenic purpura (TTP), wherein the MASP-2 inhibitory agent is an anti-MASP-2 antibody or fragment thereof.
