WEDNESDAY, Nov. 5, 2025 (HealthDay News) -- Patients with dermatomyositis who use immunostimulatory herbs before disease onset have lower positivity rates of myositis-associated autoantibodies (MAAs), myositis-specific autoantibodies (MSAs), and antinuclear autoantibodies (ANAs), according to a research letter published online Nov. 5 in JAMA Dermatology.

In a retrospective cohort study, Xiwei Yang, from the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, and colleagues examined whether commercial autoantibody testing results differ for patients with dermatomyositis that developed with versus without prior intake of immunostimulatory herbs. Positivity rates of MAAs, MSAs, and ANAs were compared for patients with versus without preonset herbal exposure; any herbal intake that lasted until three months before onset was considered relevant.

The researchers found that 36 (13 percent) of 286 patients used immunostimulatory herbs prior to developing dermatomyositis symptoms. The median time was 12 months from first herbal use to dermatomyositis onset. The most commonly taken herb was spirulina (22 of 36 [61 percent]). Compared with the nonherbal intake group, the MSA positivity rate was lower in the herbal intake group (22 versus 51 percent), as was the MAA positivity rate (13 versus 32 percent). The herbal intake group also had a lower rate of ANA positivity (40 versus 61 percent).

"Individuals susceptible to developing autoimmune responses should be counseled about the possible risk of herbal use until the pathway is further elucidated," the authors write.

Several authors disclosed ties to the biopharmaceutical industry.

Abstract/Full Text