PO:23:052 | Muscular and myocardial involvement in antisynthetase syndrome: a retrospective real-life study

Giulia Buonsante^1|2|3, Giacomo De Luca^1|2|3, Veronica Batani^1|2, Daniele Scaramuzzi^1|2|3, Lorenzo Dagna^1|2|3, Marco Matucci-Cerinic^1|2|3, Corrado Campochiaro^1|2|3. | ¹Unit of Immunology, Rheumatology, Allergy and Rare Diseases UNIRAR, IRCCS San Raffaele Hospital, Milano, Italy; ²Inflammation, Fibrosis and aging Initiative INFLAGE, IRCCS San Raffaele Hospital, Milano, Italy; ³Vita-Salute San Raffaele University, Milan, Italy, Milano, Italy.

Background. Antisynthetase syndrome (ASS) is a systemic autoimmune disease characterized by anti-aminoacyl-tRNA synthetase antibodies positivity and clinically manifested by interstitial lung disease (ILD), myositis, and arthritis. This retrospective real-life study, evaluates longitudinal changes in clinical and laboratory markers, as well as corticosteroid therapy, in muscular and myocardial involvement of ASS during the first two years after referral to our center.

Materials and Methods. We retrospectively studied 39 patients with ASS at baseline (first evaluation at our centre) and at 12 and 24 months of follow-up. Myositis and myocardial involvement were assessed, and the following parameters were recorded: CRP(mg/L), ESR(mm/h), CPK(U/L), aldolase(U/L), Troponin T(mg/L), NT-proBNP(pg/mL), and ejection fraction(%EF). Corticosteroids and immunosuppressants were also evaluated. Predictors of steroid suspension at 12 and 24 months were evaluated.

Results. In our cohort, 79% were females, median age 63 (52-70) years, median disease duration 7 (3-7.5) years. 64% were positive for anti-Jo1 antibodies. 32 (82%) patients had IIM-ILD, 26 patients (67%) had myositis, 12 (31%) had myocardial involvement. Baseline features are summarized in Table 1. Modifications in immunosuppressive therapies over time in Figure 1. Among patients with myositis, CRP levels declined at 12 months (p=0.042), and stabilized at month 24 (p=0.092). ESR levels significantly decreased at both timepoints (p=0.021, p=0.021); CPK levels dropped at both 12 and 24 months; aldolase levels remained stable (see Table 2). The % of patients on oral corticosteroids decreased from 96% at baseline, to 73% at 12 months (p=0.077) and 62% at 24 months (p=0.016), with a significant dose reduction in both timepoints (p<0.001, p=0.027). In addition, the % of patients receiving corticosteroid boluses significantly dropped from 27% at baseline, to 4% at 12 months and 0% at 24 months (p=0.002). Among patients with myocardial involvement, 9 (75%) presented with myocarditis at baseline, 4 (44%) requiring hospitalization. Troponine T and NT-proBNP declined at both timepoints (see Table 2). %Ejection Fraction assessed by echocardiography improved at both timepoints (p=0.025, p=0.001). The % of patients receiving corticosteroid pulses decreased at 12 (p=0.063) and 24 months (p=0.031). At logistic regression analysis, the positivity for anti-Ro52 antibodies was the only factor negatively associated with steroid response at 12 months (OR 0.196, 95% CI 0.043–0.899), whereas no predictor of steroid suspension at 24 months was identified.

Conclusions. In our cohort, a progressive improvement in muscular biomarkers in patients with myositis, and in cardiac function and laboratory parameters in those with myocardial involvement were observed. Over time, the use of immunosuppressants had a corticosteroid-sparing effect enabling a steroid-free remission in 38% of patients. These findings underscore the importance of a systematic assessment as well as an organ-specific follow-up in antisynthetase syndrome, suggesting that a tight follow up is needed in ASS patients to monitor disease response to treatment.