Multiple studies have investigated the role of Hp under conditions of intravascular hemolysis, but little is known about its role in the brain and following ICH where extravascular hemolysis is rampant.
Furthermore, the association between serum haptoglobin and the maximal blood flow velocity in the left ventricle outflow tract (r<sub>s</sub>=-0.42, p=0.008) indicated that intravascular hemolysis is a manifestation of the disease.
The only biologically significant role assigned to Hp by Andersen et al. is its (hypothetical) role to prevent or minimize the harmful effects of Hb during intravascular hemolysis, by the generation of reactive oxygen species (ROS) and complexing it.
Haptoglobin, the haptoglobin-hemoglobin receptor CD163, and the heme oxygenase-1 are proteins with a well-established function in the clearance and metabolism of "free" hemoglobin released during intravascular hemolysis.
The following laboratory tests were performed: prothrombin time, partial thromboplastin time, fibrinogen levels, antithrombin III, plasmatic fibronectin (as a marker of endothelial damage), haptoglobin (as a marker of intravascular haemolysis), a functional test for APC-R and analysis of factor V Leiden mutation by polymerase chain reaction.
He has been suffering from persistent hemolytic anemia characterized by marked erythrocyte fragmentation and intravascular hemolysis, with paradoxical increase of serum haptoglobin and low bilirubin.