<prompt> Donath Landsteiner antibody is seen in-PNHWaldenstroms macroglobulinemiaParoxysmal cold hemoglobinuriaMalaria  <response>: Paroxysmal cold hemoglobinuria PCHPCH is characterized by intermittent massive intravascular hemolysis frequently with hemoglobinuria at low temperature.The autoantibodies are of IgG class, also known as Donath-Landsteiner antibody.These antibodies are directed against P-antigen on RBC.Antigen-antibody complex on the red blood cell activates complement.As a result, a large amount of membrane attack complex forms which destroys red cells directly intravascular hemolysis.Causes are: - Syphilis, Mycoplasma, Mumps, Measles, Flu syndrome 