Interpretation of hemolysis tests following administration of a second-generation hemoglobin-based oxygen carrier.
Hemoglobin released into the circulation during hemolysis or therapy with chemically modified hemoglobins, exert oxidative and NO-scavenging toxic effects. Pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) is one of the second-generation hemoglobin-based oxygen carriers (HBOCs). We wanted to investigate the metabolism of PHP with a special focus on its consequences for interpreting hemolysis-related diagnostic parameters in PHP-treated patients. Clinical samples were analyzed from 3 patients, who received PHP (as part of the PHOENIX phase III trial) for treatment of catecholamine-resistant distributive shock. In contrast to expectations, clearance of PHP by hemopexin, instead of haptoglobin was documented by increased hemolysis indices, absence of decreased haptoglobin values, presence of free PHP-hemoglobin and exhausted hemopexin concentrations. The present case report is important for both clinicians and laboratorians since it nicely illustrates that a hemolytic aspect of plasma is not necessarely synonymous with hemolysis. A hemolytic aspect of plasma or serum (high hemolysis index) in combination with normal or increased haptoglobin values should draw the attention; additional determination of lactate dehydrogenase and hemopexin may then be useful to distinguish the condition from in vitro hemolysis and to monitor the in vivo elimination of the heme compounds.
Department of Laboratory Medicine, Ghent University Hospital, Belgium.
S
S
Drieghe
Department of Laboratory Medicine, Ghent University Hospital, Belgium.
V
V
Stove
Department of Intensive Care Medicine, Ghent University Hospital, Belgium.
J
J
Decruyenaere
Department of Laboratory Medicine, Ghent University Hospital, Belgium.
J
J
Delanghe
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D001802:Blood Substitutes / Q000378:metabolism* / Q000627:therapeutic use; D004909:Erythrocyte Indices; D016166:Free Radical Scavengers; D006242:Haptoglobins / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D008264:Macrophages / Q000378:metabolism; D011092:Polyethylene Glycols / Q000378:metabolism* / Q000627:therapeutic use; D011956:Receptors, Cell Surface; D012769:Shock / Q000097:blood / Q000628:therapy; D000098902:CD163 Antigen
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D001802:Blood Substitutes; D000098902:CD163 Antigen; D016166:Free Radical Scavengers; D006242:Haptoglobins; D006454:Hemoglobins; D011956:Receptors, Cell Surface; C035492:haptoglobin-hemoglobin complex; C050907:pyridoxalated-hemoglobin-polyethylene glycol conjugate; D011092:Polyethylene Glycols