In one aspect, the invention provides methods of inhibiting the effects of MASP-2-dependent complement activation in a human subject suffering from persistent TMA associated with hematopoietic stem cell transplant. The methods comprise the step of administering, to a subject in need thereof, a dosage of 4mg/kg at least weekly for a period of at least 3 weeks of a MASP-2 inhibitory agent effective to inhibit MASP-2-dependent complement activation.