Immunostimulatory herbal intake and autoantibody positivity in dermatomyositis

Summary: Abstract Body: Herbal supplements are popular among the general population, but lab studies have shown that they can activate immune cells and thus precipitate dermatomyositis (DM) onset or flare in susceptible individuals. We sought to assess if real-world autoantibody testing results differ between DM developed with and without prior intake of high-risk herbs. In this retrospective cohort study, patients in the Penn DM database were screened for use of immunostimulatory herbs including alfalfa, ashwagandha, chlorella, echinacea, elderberry, spirulina, and tongkat ali. Autoantibody status was recorded for myositis-associated (MAA), myositis-specific (MSA), and antinuclear (ANA) antibodies. MAA included SSA, Pm-Scl, Ku, U1-RNP, U2-RNP, and U3-RNP. MSA included Jo-1, PL-7, PL-12, EJ, OJ, Mi-2, SRP, TIF-1γ, NXP-2, MDA5, and SAE. Autoantibody positivity rates in patients with and without relevant herbal exposure before DM onset were compared using chi-square and Fisher’s exact tests. Out of 286 patients, 36 (13%) were on immunostimulatory herbs prior to developing DM symptoms; the median time from first herbal use to DM onset was 12 months. MSA positivity rate in this herbal group was 22% (8/36) compared to 51% (128/250) in patients without pre-onset herbal intake, p = 0.001. MAA was positive in 13% (4/31) of the patients who took herbs before DM onset vs. 32% (64/202) of those who did not, p = 0.03. ANA positivity rate was also lower in the herbal group (40%, 10/25) than in patients without herbal triggers for their DM onset (61%, 108/176), p = 0.04. Spirulina (22/36) was most commonly taken followed by elderberry (9/36) and ashwagandha (4/36). We found that MSA, MAA, and ANA positivity rates were significantly lower in patients whose DM was potentially triggered by immunostimulatory herbs. Since herbal supplements can lead to new DM onset in the absence of autoantibodies, physicians should consider clinical findings and screen for herbal intake when diagnosing DM. X. Yang^{1, 2}, A. On^{1, 2}, S. Chambers^{1, 2}, H. Ali^{1, 2}, T. Hafshejani^{1, 2}, L. Gomes^{1, 2}, V. Werth^{1, 2} 1. Dermatology, U Penn, Philadelphia, PA, United States. 2. CMCVAMC, Philadelphia, PA, United States. Clinical Research: Epidemiology and Observational Research