AUTHOR=He Lingbo , Yao Shuyan , Zhang Ruoxi , Liu Menghan , Hua Zhengjie , Zou Heshan , Wang Zhao , Wang Yini TITLE=Macrophage activation syndrome in adults: Characteristics, outcomes, and therapeutic effectiveness of etoposide-based regimen JOURNAL=Frontiers in Immunology VOLUME=Volume 13 - 2022 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.955523 DOI=10.3389/fimmu.2022.955523 ISSN=1664-3224 ABSTRACT=Objectives. To describe the clinical characteristics and outcomes of adult macrophage activation syndrome (MAS) patients and to provide experience for the treatment. Methods. Adult patients with MAS admitted to Beijing Friendship Hospital from December 2014 to September 2021 were enrolled in this study. Clinical data of patients were collected and analyzed. Results. A total of 118 adult MAS patients entered this study. MAS was the first manifestation in 43 (36.4%) patients, while 75 (63.6%) developed MAS after the diagnosis of autoimmune disease (AID) with a median diagnostic interval of 2 (0.5-359) months. Eighty-two patients were initially treated with glucocorticoid-based regimen, the overall response (OR) rate at 2-week post-treatment was 37.8%. Forty-five patients switched to etoposide-based regimen, the OR rate was 84.4%. Thirty-six patients were initially treated with etoposide-based regimen, and the OR rate at 2-week post-treatment was 80.6%. Serum IL-18 (P=0.021), IFN- (P=0.013), IP-10 (P=0.001), IL-10 (P=0.041), IL-1RA (P<0.001), and TNF- (P=0.020) level of patients were significantly decreased in the remission phase than active phase. Levels of SDF-1α (P=0.018) and IL-7 (P=0.022) were higher in refractory patients, while GRO-α level had a strong tendency towards statistical significance (p=0.050). The probability of overall survival (OS) at 3, 6 and 36 months after HLH diagnosis were 89.8%, 89.0%, and 87.9%, retrospectively. Active MAS status at 2-week post initial treatment [P=0.009, HR=15.281, 95%CI, (0.1.972, 118.430)], baseline neutrophil count (Neu) <1.5109/L [P=0.017, HR=3.678, 95%CI, (1.267, 10.672)] were negative prognostic factors. Conclusion. MAS typically occurs within 2 months after the onset of autoimmune disease in adults. SDF-1α, IL-7 and GRO-α could be used to predict refractory MAS. Etoposide-based regimen is effective and tolerable for adult MAS.