Sarcoidosis is linked with higher risk of autoimmune disorders…

People with sarcoidosis in the U.S. are more likely than those in the general population to have certain co-occurring autoimmune disorders, including lupus and multiple sclerosis (MS).

That’s according to “Autoimmune comorbidities associated with sarcoidosis: a case-control study in the All of Us research program,” which was published in Rheumatology Advances in Practice.

The results “underscore the need for a thorough clinical history and review of systems when evaluating sarcoidosis patients, followed by appropriate screening for co-morbid autoimmune diseases as indicated,” said the study’s authors.

Sarcoidosis is an inflammatory disorder wherein clumps of immune cells called granulomas form in various organs throughout the body. Some researchers consider sarcoidosis to be an autoimmune disorder, that is, a disease caused by the immune system attacking healthy parts of the body. Others say it isn’t technically an autoimmune disorder because a clear molecular target driving the autoimmune attack hasn’t been identified.

Increased risk of MS, lupus, scleroderma

One hallmark of autoimmune disorders is that they tend to co-occur. People with one autoimmune disease typically have a greater risk of developing others. There hasn’t been much research into the risk of co-occurring autoimmune diseases with sarcoidosis, however, leading a team of scientists to analyze data from All Of Us, a national study assessing genetics and healthcare outcomes in the U.S.

The researchers identified 1,408 people with sarcoidosis and a matched control group of 5,632 who didn’t have the disease, but were similar in age, sex, and race. In both groups, the average age was 63 and about two-thirds were female, with 46% identified as white, 39.8% as Black, and 10.8% as Hispanic.

The researchers used statistical tests to compare rates of two dozen different autoimmune conditions in the sarcoidosis patients and controls. All 24 autoimmune disorders analyzed were numerically more common among sarcoidosis patients, but only seven were statistically significant. These included lupus and multiple sclerosis, as well as systemic sclerosis, rheumatoid arthritis, vitiligo, alopecia areata, which is characterized by hair loss, and vasculitis, or blood vessel inflammation.

The analysis was limited by its reliance on database records and, because sarcoidosis symptoms may resemble those in other conditions like rheumatoid arthritis, it’s feasible that incorrect diagnoses may have affected some outcomes. Still, the researchers said other studies have also suggested a connection between sarcoidosis and autoimmune diseases like lupus and MS, so the finding “builds upon previous research demonstrating an association between sarcoidosis and multiple autoimmune diseases.”

The data also support the idea that sarcoidosis is a true autoimmune disease, though more research is needed to understand its molecular causes, the scientists said.