Rheumatoid arthritis is associated with an atypical immune response called a type 3 hypersensitivity reaction. This reaction happens due to immune complexes in the body. It can be treated by suppressing immune activity.

person with rheumatoid arthritis holding a painful wrist-1Share on Pinterest
Johnce/Getty Images

Rheumatoid arthritis (RA) is an autoimmune disease that affects about 1.3 million people in the United States. The effects of RA lead to joint pain, stiffness, and swelling. Sometimes RA can affect other parts of the body as well.

RA is associated with an inappropriate immune response to a substance called an antigen in your body. The process is called a hypersensitivity reaction.

There are four different types of hypersensitivity reactions. We discuss the RA hypersensitivity type, what causes it, and how this type of reaction is diagnosed and treated.

A hypersensitivity reaction is an inappropriate or abnormal response to an antigen. These reactions are the mechanism behind certain health conditions involving the immune system, such as autoimmune diseases and allergies.

Experts have divided hypersensitivity reactions into four different types. These are generally based on the parts of the immune system involved in the reaction.

RA is a type 3 hypersensitivity reaction, which is caused by complexes formed by antigens and immune proteins called antibodies.

The symptoms of a type 3 hypersensitivity reaction can vary. In this case, the RA hypersensitivity reaction leads to the symptoms that we commonly associate with RA, such as:

Some people with RA may also develop firm lumps under the skin near the affected joints called nodules.

RA-related inflammation can also affect other areas of the body, including the eyes, lungs, and heart.

A type 3 hypersensitivity reaction happens due to immune complexes formed by antibodies and antigens. Antibodies are a type of protein made by the immune system. They’re specific for certain types of antigens.

When antibodies bind to their antigen, they form an antibody-antigen, or immune, complex. Immune complexes can accumulate in certain tissues like the joints, skin, or blood vessels.

RA is associated with autoantibodies, specifically rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (ACPA). These bind to antigens on healthy tissue, such as the tissues of the joints, and form immune complexes.

The presence of immune complexes can activate a type of immune response called complement. Complement activation has been associated with the initiation and progression of RA.

When the complement system is activated, it basically calls other types of immune cells into the affected area. The arrival of these cells can lead to increases in inflammation and tissue damage.

If you have RA symptoms, a healthcare professional will first request your medical history. They’ll ask about your symptoms, when they started, what makes them better or worse, and whether you have a family history of autoimmune diseases like RA.

They’ll also perform a physical exam. During this time, they’ll evaluate the affected joints, checking for pain, stiffness, and warmth.

If a healthcare professional suspects RA based on your medical history and physical exam, they’ll order additional tests to help make a diagnosis.

There isn’t a single test that can diagnose an RA hypersensitivity reaction. Some of the tests that may be used include:

The treatment for a type 3 hypersensitivity reaction involves managing the underlying disease. This typically involves dampening down the immune response to lower inflammation and prevent additional tissue damage.

Medications can be used to achieve this goal. The medications prescribed for RA can depend on the severity of your RA.

  • Traditional disease-modifying antirheumatic drugs (DMARDs): DMARDs like methotrexate and sulfasalazine are often first-line treatments for RA. These medications reduce the immune response more broadly.
  • Corticosteroids: Corticosteroids can lower inflammation caused by RA. These are typically used on a short-term basis to manage an RA flare-up.

There’s no cure for the type 3 hypersensitivity reaction that leads to RA. Instead, its effects are managed through medications.

It’s important that RA is diagnosed and treated early. That’s because tissue damage can worsen over time if RA is not managed. This can lead to significant joint deformities and disability.

One goal of RA treatment is putting the disease in remission. You’re in remission when you have no visible symptoms of RA.

One 2022 study found that 76% of participants who had remission 1 year after diagnosis continued to retain that remission over a 7-year follow-up period. Low RA disease activity at diagnosis and the use of traditional or biologic DMARDs were associated with remission.

What type of hypersensitivity is rheumatoid factor?

RF is an autoantibody that’s involved in forming the immune complexes associated with the type 3 hypersensitivity reaction seen in RA.

What are other examples of type 3 hypersensitivity reactions?

A few examples of other conditions associated with a type 3 hypersensitivity reaction include systemic lupus erythematosus (SLE), serum sickness, and hypersensitivity pneumonitis (farmer’s lung).

Is rheumatoid arthritis a type 4 hypersensitivity reaction?

No. RA hypersensitivity is a type 3 reaction. Type 4 hypersensitivity reactions are cell-mediated, meaning they do not involve antibodies. Examples of type 4 reactions are allergic contact dermatitis and delayed reaction to drugs.

RA is associated with a type 3 hypersensitivity reaction. These types of reactions are caused by immune complexes that accumulate in certain areas of the body, such as the joints in RA.

There’s no specific test for type 3 hypersensitivity reactions. Instead, a healthcare professional will use your medical history and the results of a physical exam, blood tests, and imaging tests to make a diagnosis.

The RA hypersensitivity reaction can be treated by lowering immune activity. The outlook for a person with RA is better with early diagnosis and treatment. It’s important to see your doctor if you have symptoms like fatigue and joints that are often sore, stiff, and swollen.