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About PNH

A Disease That Causes Ongoing Red Blood Cell Destruction (Haemolysis)

Paroxysmal nocturnal heamoglobinuria (PNH) is an acquired disease that causes some or all of your body’s red blood cells (RBCs) to be destroyed by a process called haemolysis.1-3  PNH is a complex disease with signs and symptoms that are nonspecific, unpredictable, and often similar to those of other diseases. In addition, PNH presents uniquely in each person. If you have PNH, some or all of your RBCs may be missing an important protective protein. Without this protein, some RBCs are prone to destruction by a part of your body's defence system called complement.1-3

Even though you can't feel it, haemolysis is constant, silent1, and can be life threatening.1-3 Like other chronic diseases, such as diabetes or hypertension, PNH can result in serious health problems if not treated. Common symptoms associated with PNH include stomach pain, difficulty swallowing, anaemia, shortness of breath, and tiredness (fatigue). More serious complications can include blood clots, kidney failure, and damage to vital organs.1-3 People with PNH may have different symptoms that can unpredictably get worse (such as during times of stress) or better from time to time. However, all people with PNH experience chronic haemolysis.

People with PNH may have other medical conditions that affect the function of their bone marrow such as aplastic anaemia (AA) or myelodysplastic syndromes (MDS). Unlike PNH, which destroys RBCs, these diseases may reduce the production of blood cells and further complicate PNH.1-3-4 If you have PNH in combination with AA or MDS, talk to your doctor — it's important to effectively treat all the conditions you may have.


PNH RBCs lack an
important protein.

Complement Attack

Without this protein, some RBCs can be destroyed by complement, one of the body's defence systems.

PNH RBC Lysis (haemolysis)

PNH RBCs are destroyed, and the toxic contents are released into surrounding plasma (yellow-colored liquid component of blood).

References: 1. 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. 2. Hillmen P, Lewis SW, Bessler M, Luzzatto L, Dacie JV. Natural history of paroxysmal nocturnal haemoglobinuria. N Engl J Med. 1995;333:1253-1258. 3. Nishimura J-I, Kanakura Y, Ware RE, et al. Clinical course and flow cytometric analysis of paroxysmal nocturnal haemoglobinuria in the United States and Japan. Medicine. 2004;83:193-207. 4. Brodsky RA. Paroxysmal nocturnal haemoglobinuria. Hematology : Basic Principles and Practice. 4th ed. Philadelphia, PA : Elsevier Churchill Livingstone ; 2005: 419-427.