Psoriatic Disease and Your Immune System

Researchers believe that psoriatic disease (PD) is an autoimmune disease. That means that both psoriasis and psoriatic arthritis (PsA) are caused by your immune system becoming overactive. 

While both conditions are lifelong, treatment can help to stabilize and regulate the overactive process of the immune system, allowing you to better manage your symptoms.

How Does the Immune System Work?

Your immune system is supposed to protect against infection and diseases through inflammation. It does this by sending immune cells and blood to parts of the body it feels are threatened. For example, if you fall and scrape your elbow, it will swell and become red as your immune system’s inflammatory response works to heal the injury.

The immune system works with both your circulatory and lymphatic systems. This involves the transportation of antigens and pathogens to lymph nodes and/or the spleen for processing and eradication. Immune cells, including phagocytes and neutrophils, circulate through the circulatory system to the location of the pathogens—either in the lymph nodes or spleen—to overwhelm and destroy foreign invaders.

The immune system works to eradicate pathogens with help from the integumentary system. The integumentary system is made up of all the skin cells of the body. Both the skin and the immune system work together to keep foreign pathogens out of the body. Interestingly, the skin is the first line of defense because it acts as a barrier to the inner body.

PD and Your Immune System

With PD and other autoimmune diseases, your immune system—which is designed to keep you healthy—suddenly makes you sick. The reason for this is autoimmunity, a process whereby the immune system launches inflammatory attacks against the body it is supposed to protect.

To some degree, autoimmunity is present in everyone and tends to be harmless; for example, the body may produce antibodies against itself (proteins called autoantibodies) to help clean up after an infection. But it can also cause a broad range of autoimmune diseases, which can result in the gradual progression of autoimmunity. Such progression is related to genetics and environmental triggers.

When a person has PD, their immune system does not work properly. It makes too much of certain proteins that cause the body to think it is being attacked. In turn, the body responds with inflammation. Inflammation then affects skin cells and makes them grow too quickly. It also affects the joints, which become painful, stiff, tender, and swollen as a result of ongoing inflammatory processes.

Treatment

The immune system might cause PD, but it is also the key to treating it. Medications that suppress the overactive immune system can clear skin and halt inflammation in joints. Thanks to science, there are many effective treatments directed toward the immune system for treating PsA and psoriasis.

The target-to-treat (T2T) approach is used for treating PD and involves finding a target goal—either remission or minimal disease activity—and working toward that goal at a quick pace. In 2017, the Annals of Rheumatic Disease published specific T2T recommendations for rheumatologists to follow in treating people with PsA and psoriasis. Those recommendations suggest the target should be either clinical remission or low disease activity.

One T2T trial from 2015 published in The Lancet confirms a T2T approach does make a difference in improving outcomes for people with PsA and psoriasis. In the clinical trial, 206 people with early PsA were randomized to receive standard care or tight control and management for 48 weeks. The tight-control group saw their healthcare providers once a month. Using specific targets and treatments, the tight-control group was treated with disease-modifying antirheumatic drugs (DMARDs) with a target goal of minimal disease activity. The standard-care patients were seen every 12 weeks, and they were treated as their healthcare providers deemed appropriate, but with no set goals.

While there is no cure for PD, current treatment methods aim to relieve pain, reduce inflammation, keep joints moving, thwart joint and skin symptoms, and prevent disability. Specific therapies for PD include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, disease modifying anti-rheumatic drugs (DMARDs), biologics, and topical treatments. NSAIDs, corticosteroids, and topical treatments mainly relieve symptoms, while DMARDs and biologics affect the overactive responses of the immune system.

The most common DMARD prescribed for people with PD is methotrexate, which is a systemic drug that suppresses the immune system.

Biologics are newer medications that act on specific parts of the immune system to treat PD. These medications are made from biological materials and mimic normal immune system cells, proteins, and antibodies. They are highly targeted, which means they have fewer side effects than other treatments. The biologics Enbrel (etanercept), Cosentyx (secukinumab), and Humira (adalimumab) are commonly prescribed to treat PD.

Biologics work by blocking immune-system proteins, so they reduce the ability of the immune system to attack your body. Because they blunt immune function, taking biologics slightly increases your risk for infection. 

A Word From Verywell

Researchers are working hard to understand the complex relationship between the immune system and PD. They want to identify specific antigens that trigger autoimmunity in people with PsA and psoriasis in order to create treatments to target specific inflammation-producing proteins. Until then, PD is treatable and manageable. Work with your healthcare provider to find the best plan for managing joint and skin symptoms, and make sure you are doing your part in caring for your own health and well-being.