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
