Multiple sclerosis is a chronic neurodegenerative disorder caused by the body’s autoimmune attack of the protective covering that surrounds nerves in the body. This substance is called myelin and diseases that involve deterioration of the myelin sheath are termed demyelinating diseases.
Beta interferons are relatively new agents in the treatment of patients with multiple sclerosis. These agents are only useful for treating the relapsing remitting and secondary progressive forms of multiple sclerosis and not primary progressive multiple sclerosis.
Interferons were first isolated and discovered in 1957 by two biologists, Alick Isaacs from Great Britain and Jean Lindenmann from Switzerland. Interferons exist in three forms - alpha, beta and gamma, and these are grouped into two types. Type 1 includes the alpha and beta interferons, which are produced by almost all cells in the presence of a virus. Type 2 interferon or gamma interferon is produced only by natural killer cells and T lymphocytes.
The role of type 1 interferon is to promote viral resistance in cells and the role of type 2 interferon is to flag up the presence of the infectious agents or cancerous growths for immune attack. Studies have shown that interferon gamma itself may contribute to the underlying pathology in multiple sclerosis. The promotion of inflammation by gamma interferon is thought to be involved in exacerbations of the condition and although it was once used as a treatment for the condition, it was found to worsen the disease by increasing destruction of the myelin sheath.
Interferon beta on the other hand, acts as an immune suppressor, increasing the activity of suppressor lymphocytes and inhibiting the activation of other immune cells. Two types of beta interferon are used to treat multiple sclerosis. Betaseron is an interferon beta 1b agent and Rebif and Avonex are examples of interferon beta 1a agents.
As well as suppressing the inflammation that can damage the myelin sheath, interferon beta 1b can regulate the production of gamma interferon. The net effect in multiple sclerosis is a reduction of the immune response directed at myelin in the central nervous system. Interferon beta 1a is a slightly different form of interferon beta that is produced in hamster cells using recombinant DNA technology.
Beta interferon medications can cause flu-like symptoms such as fever, muscle ache, headache and chills. Symptoms usually pass after 48 hours but patients can take ibuprofen or paracetamol to ease these side effects. Injecting the drugs prior to bedtime in addition to taking ibuprofen or paracetamol may help a patient sleep through the worst of these effects.
Reviewed by Sally Robertson, BSc