Emerging Areas of Research for Psoriatic Arthritis

Psoriatic arthritis (PsA) affects about 1 million people in the United States. In the past few decades, areas of research for PsA have evolved. Researchers are working to better understand the disease so doctors can diagnose it earlier and find more effective treatments.¹

Many factors affect how PsA and psoriasis develop. These factors range from genes and gut bacteria to environmental triggers like smoking and infection. By understanding these factors, researchers can develop new, more efficient treatments.^2,3

Biomarkers

Biomarkers are signals within the body that can be measured. For instance, blood pressure and heart rate are biomarkers. Biomarkers can provide key insight into a disease, how it progresses, and how well treatment works. Biomarkers can also help predict whether a person is at risk for a disease.³

At this time, there are no clear biomarkers for PsA, but researchers are working to find them. For example, 85 percent of people with PsA have psoriasis first. This has led researchers to look for biomarkers that can show which people with psoriasis might develop PsA.³

Several biomarkers show promise in how PsA emerges and progresses. They can also help predict which treatment will be most effective. These include:³

• Interleukins (IL) and T-helper (Th) cells – Chemical messengers (interleukins) and T-helper cells are linked with PsA. Scientists believe that IL-17, IL-22, IL-23, and Th-17 contribute to inflammation.
• Human leukocyte antigens (HLA-A, HLA-B, and HLA-C) – The HLA system allows the immune system to identify healthy cells versus foreign invader cells. Different combinations of HLAs are linked with mild and severe PsA.
• Advanced imaging – Magnetic resonance imaging (MRI) and ultrasound help researchers see changes in joints in people with psoriasis. These changes are sometimes early predictors of PsA.
• Osteoclast precursors – These cells are the early form of cells that break down bone. For people with PsA, this process gets triggered. It then can cause joint damage and deformity. High levels of osteoclast precursors could be a predictor of PsA.

Biologic treatment targets

While there is no cure for PsA, some biologic treatments can provide periods of remission. Biologics are drugs made from living cells. These cells can come from parts of the blood, proteins, viruses, or tissue. The process of making biologics turns these cells into drugs that can prevent, treat, and cure disease.^4,5

Traditionally, many people with PsA have been treated with disease-modifying anti-rheumatic drugs (DMARDs). In recent years, more DMARDs have been developed that are biologics. These drugs target specific areas of the immune system. This can make them more effective for some people.^4,5

Researchers are searching for new targets for biologics, including:^4,5

• T-cell activation – T-cells are a type of white blood cell that is activated during an immune response. These cells are overly active in PsA. Experts are searching for what triggers these T-cells so it can be targeted.
• Interleukin 17A (IL-17A) – IL-17A increases inflammation in PsA. Drugs that block IL-17A work in some people with medium to severe psoriasis. IL-17A inhibitors are being tested on people with PsA.
• Interleukin 6 (IL-6) – IL-6 is another cytokine that plays an important role in the disease progression of PsA. Drugs that block IL-6 might be effective.
• Janus kinase (JAK) – This family of enzymes plays a role in inflammation. JAK inhibitors stop the activity between these enzymes.

The link between PsA and the gut

There is research about how the gut microbiome and the immune system work together. The gut microbiome includes trillions of good bacteria and microorganisms that live in a person’s digestive tract.²

In a 2019 study, a person with PsA was treated for a Clostridioides difficile (C. diff, previously Clostridium difficile) infection with a fecal microbiota transplantation (FMT). In a FMT, good microorganisms from a donor's stool are introduced into a person. Investigators found that since getting the FMT, this person's PsA has been in remission.²

This study suggests that the gut microbiome could affect the inflammation that causes PsA. More studies are exploring the connection between the gut microbiome and PsA.^2,3

Precision medicine

Precision medicine tailors treatment to a specific person. It is a personalized form of therapy. In the past, PsA has been treated with a trial-and-error approach using DMARDs. This was followed by biological DMARDs if initial treatment did not work. But that treatment approach is not a good fit for everyone.^2,4

Researchers are looking at how precision medicine can help treat PsA. They are trying to:^2,4

• Identify more biomarkers that can predict PsA development
• Identify better targeted drug treatments
• Use next-generation sequencing to find new pathways and cells tied to PsA
• Understand the interactions between the gut microbiome and immune cells

The more information they gather, the more personalized treatment options there will be for people with PsA.

Be a partner in your PsA treatment

It is important for everyone to be an advocate for their own health. A 2020 study found this to be especially true for people with PsA. When those with PsA contributed to the research agenda, experts better understood the disease. By involving study participants, scientists gained valuable insights into the condition.⁵

Your unique perspective on your disease can help improve treatment options and therapies in the future. Partner with your doctor and healthcare team. Share your insights with them. It could make a difference in your treatment.