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Role of Haemolysis

The Role of Haemolysis in PNH

Haemolysis is a medical way of saying "destruction of red blood cells." Haemolysis is measured by LDH (lactate dehydrogenase, an enzyme found in red blood cells) and elevated levels of LDH are an indicator of excessive haemolysis.1 In healthy people, low levels of haemolysis are constant and naturally occurring. However, in people with PNH, there is excessive haemolysis resulting from a missing protective surface protein on some or all RBCs. This excessive haemolysis releases the toxic contents of RBCs into the bloodstream, which, over time, can cause many of the symptoms associated with PNH and harm important organs in your body.

If you have PNH, haemolysis is always taking place — whether you feel OK or whether you’re having a flare-up (paroxysm), such as during times of stress or infection.1-2 Excessive and continual haemolysis is the main cause of major health problems in PNH.

Why is haemolysis important?

When blood cells are destroyed, their toxic contents are released into the bloodstream and can build up, causing health problems that can occur suddenly at any time.1 These problems can include kidney failure and serious blood clots, which may cause damage to important organs like your liver, brain, and lungs.1,3-5

Haemolysis also affects the way you feel. Many people with PNH report that the unpredictability of the frequency and severity of their symptoms impairs their quality of life. Physicians believe reducing chronic haemolysis is an important goal in PNH treatment.6

References: 1.Brodsky RA. Paroxysmal nocturnal haemoglobinuria. Hematology : Basic Principles and Practice. 4th ed. Philadelphia, PA : Elsevier Churchill Livingstone ; 2005: 419-427. 2. Nakakuma H. Mechanism of intravascular haemolysis in paroxysmal nocturnal haemoglobinuria (PNH). Am J Hematol. 1996 ; 53 (1): 22-29. 3. Hillmen P, Lewis SM, Bessler M, Luzzatto L, Dacie JV. Natural history of paroxysmal nocturnal haemoglobinuria. N Engl J Med. 1995;333:1253-1258. 4. Socié G, Mary J‐Y, de Gramont A, et al, for the French Society of Haematology. Paroxysmal nocturnal haemoglobinuria: long-term follow-up and prognostic factors. Lancet. 1996;348:573-577. 5. Moyo VM. Natural history of paroxysmal nocturnal haemoglobinuria using modern diagnostic assays. Br J Haematol. 2004; 126:133-138. 6. Meyers G et al. Disease-related symptoms reported across a broad population of patients with Paroxysmal Nocturnal Haemoglobinuria. Blood. 2007; 110(11): Abstract 3683