About Paroxysmal Nocturnal Hemoglobinuria (PNH)

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, chronic, and potentially life-threating blood disorder that occurs when unregulated complement activity causes the destruction of red blood cells (hemolysis) and the formation of life-threatening blood clots (thrombosis).1,2
PNH can affect people of any age, race, or gender.1,2 In PNH, the body’s stem cells acquire a gene mutation which results in the production of abnormal blood cells that lack two important surface proteins that act as a shield to protect the body from attack and destruction by complement, an important part of the body’s immune system.³ As a result, the complement protein C3 becomes overactivated in patients with PNH, which triggers two types of hemolysis at the same time:4,5
• Intravascular Hemolysis: occurs when the formation of membrane attack complexes (MACs) creates holes in red blood cells, causing them to rupture inside blood vessels
• Extravascular Hemolysis: occurs when C3b is deposited on the surface of defective red blood cells, tagging them for removal and destruction in the liver and spleen
This continued hemolysis can result in a chronic shortage of healthy red blood cells (severe anemia) and other symptoms such as kidney failure, high blood pressure in the lungs, abdominal pain, shortness of breath, blood in your urine, problems swallowing, erectile dysfunction, and fatigue.⁶ In addition to controlling anemia, re-establishing control of the complement system can help to reduce transfusion dependence and the risk of blood clot formation (or thrombosis) which is the leading cause of mortality in patients with PNH.⁶
Learn more about this disease and a potential cure at pnhstudy.com
1. Paroxysmal nocturnal hemoglobinuria (PNH). The Sidney Kimmel Comprehensive Cancer Center Web site. www.hopkinsmed... Accessed May 15, 2018.
2. Besa EC. Paroxysmal nocturnal hemoglobinuria (PNH) MedScape 2017; emedicine. medscape.com/article/207468-overview. Accessed May 15, 2018.
3. Rosse WF, Ware RE. The molecular basis of paroxysmal nocturnal hemoglobinuria. Blood. 1995;86(9):3277-3286.
4. Hill A, Kelly RJ, Hillmen P. Thrombosis in paroxysmal nocturnal hemoglobinuria. Blood. 2013;121(25):4985-4996; quiz 5105.
5. Parker C, Omine M, Richards S, et al. Diagnosis and management of paroxysmal nocturnal hemoglobinuria. Blood. 2005;106(12):3699-3709.
6. Data on file, Apellis Pharmaceuticals.