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The immune system plays a vital role in keeping the body healthy. It is made up of a complex network of cells and organs that work together to defend the body against foreign invaders.

Biologic agents use the body’s own immune system to help fight disease. While traditional pharmaceuticals are made up of chemicals, biologic agents are actually developed using proteins from living cells. They are designed to act on different parts of the inflammatory system in order to evoke specific, targeted effects.

Biologic Agents and the Treatment of Autoimmune Disorders

In autoimmune disorders, the immune system is overactive and destroys not only foreign substances, but also the body’s own tissues. The goal of biologic therapy is to slow or block specific components of the immune system and halt tissue destruction.

Autoimmune disorders treated with biologic agents include:

  • Psoriasis: This is a chronic skin disorder that not only causes skin lesions, but also problems with the joints, fingernails and toenails, genitals, and inside of the mouth. In psoriasis, certain immune cells become overactive, which results in psoriatic lesions developing on the skin and arthritis symptoms developing in the joints.
  • Rheumatoid arthritis (RA): RA is a chronic inflammation of the lining of the joints that results in pain, stiffness, swelling, damage, and loss of function. In RA, the immune system initiates chronic inflammation of the lining of the joints.
  • Multiple sclerosis (MS): MS is a chronic debilitating disease in which patches of white matter in the central nervous system become inflamed and destroy the insulation (myelin) of the nerve fibers in the brain and spinal cord. In MS, antibodies and white blood cells are responsible for the attack on the myelin sheath that surrounds nerves in the brain and spinal cord, causing inflammation and injury to the sheath and the nerves.

Side Effects of Biologic Agents

Because biological agents are very specific in their targets and more precise and predictable, they tend to produce fewer side effects and undesirable consequences than traditional medicines, which are manufactured through synthetic chemical means.

Side effects depend on many factors such as the type of biologic, dosage, route of administration, schedule, and how your body reacts to the biologic agents. Some of the most common side effects of biologic therapies are:

  • Flu-like symptoms (fever, chills, muscle and joint aches)
  • Loss of appetite
  • Nausea and/or vomiting
  • Fatigue
  • Redness, rash, and/or pain at injection site
  • Headache
  • Possible allergic reaction to mouse protein with monoclonal antibodies
  • Increased risk of Hodgkin’s and non-Hodgkin’s lymphoma and other types of cancer in children and teens taking TNF inhibitors
  • Lupus-like syndrome
  • Possible reactivation of latent tuberculosis infections with TNF inhibitors

A Step Forward in Medicine

Many biologic agents have been approved by the FDA (see the following table), and many more are under development.

Examples of Approved Biologic Agents for Autoimmune Disorders

Brand name

Biologic Agent

Disease State




Raptiva *








psoriatic arthritis; rheumatoid arthritis; juvenile rheumatoid arthritis and more



rheumatoid arthritis, crohn's disease, psoriasis and more



rheumatoid arthritis; Crohn’s disease



rheumatoid arthritis

Avonex, Rebif

interferon beta

multiple sclerosis

* In April 2009, the manufacturer of efalizamab (Raptiva) voluntarily decided to remove it from the market. The medicine has been linked to a rare brain infection that can be life-threatening. If you are currently taking Raptiva, talk to your doctor about other treatments.