Why Rheumatoid Arthritis May Actually Be 2 Different Diseases

Share on PinterestResearchers say rheumatoid arthritis can be divided into two types: people with autoantibodies…

Why Rheumatoid Arthritis May Actually Be 2 Different Diseases

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Researchers say rheumatoid arthritis can be divided into two types: people with autoantibodies and those without them. Getty Images
  • Researchers say rheumatoid arthritis may actually be two diseases instead of just one.
  • They recommend that the disease be divided into two types: people with autoantibodies and people without them.
  • They say people with autoantibodies appear to have better long-term outcomes in the reduction of rheumatoid arthritis symptoms.

It’s bad enough that rheumatoid arthritis (RA) exists as even one disease.

But now, a new study concludes that the debilitating condition may actually be two different diseases.

In addition, researchers say one subtype of RA may lead to poorer outcomes than the other.

Their research was published this week in the journal PLOS Medicine.

The study was conducted by Dr. Xanthe Matthijssen, a researcher at Leiden University Medical Center in the Netherlands, and her colleagues.

The scientists say there are indications that RA can be split into two distinct categories: with and without autoantibodies.

While disease activity tends to often improve over time for many people with rheumatoid arthritis, it seems that the long-term outcomes might only improve in people with autoantibodies.

Autoantibodies are a type of antibody produced by a faulty immune system.

They target one or more of a person’s healthy proteins, cells, tissues, organs, and joints.

Many times, this reaction leads to inflammation. These autoantibodies are a part of most autoimmune diseases.

Another explanation is that autoantibodies may be produced by a person’s immune system when it, for whatever reason, fails to distinguish between “self” (parts of the person’s body) and “nonself” (a virus, for example).

In rheumatoid arthritis, the immune system attacks healthy cells in the joints.

In recent years, it has become more apparent that there are noticeable differences among people who have RA-associated autoantibodies detectable in their bloodstream versus those who do not.

The latter group is known as autoantibody-negative RA.

This latest study on RA autoantibodies looks at how these immune proteins in both positive and negative patients play into longer-term disability and recovery.

The researchers followed 1,285 people with RA between 1993 and 2016 through the Leiden Early Arthritis Clinic cohort.

During this time, data on symptoms, treatments, disability, and mortality was collected annually.

Whether or not participants had the autoantibodies or not was noted.

Of the 1,285 people, researchers found that 823 people had autoantibody-positive RA. The remaining 462 participants had RA that was categorized as autoantibody-negative.

It’s worth noting that in both of these groups, the overall disease activity decreased significantly over time.

That said, the sustained drug-free remission rates increased only in autoantibody-positive participants but not in those who were autoantibody-negative.

Mortality and functional disability rates also decreased with targeted treatment adjustments in autoantibody-positive participants and not among those who were autoantibody negative.

“The disconnection between improvement in disease activity and subsequent improvement in long-term outcomes in RA without autoantibodies suggests that the underlying pathogenesis of RA with and without autoantibodies is different,” the study authors said in a public press release.

“We propose that it is time to formally divide RA into type 1, with autoantibodies, and type 2, without autoantibodies, in the hope that it leads to stratified treatment in autoantibody-positive and autoantibody-negative RA,” they said.

Matthijssen also noted in the statement that in the past decade, “Research in RA has largely focused on the autoantibody-positive subset. More research on autoantibody-negative RA is urgently needed to identify methods to also improve their long-term outcomes.”

Cindy McGill, a Rhode Island resident who has rheumatoid arthritis, found the research enlightening.

“I didn’t know about the different kinds of rheumatoid disease, but now I’m curious. I would like to know what type of RA I have,” she told Healthline.

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