Predictive factors for the recurrence of anti-aminoacyl-tRNA synthetase antibody-associated interstitial lung disease

Anti-synthetase syndrome (ASS) is characterized by the presence of anti-aminoacyl-tRNA synthetase antibody and ASS-associated interstitial lung disease (ILD) often recurs. The effectiveness of remission induction therapy with corticosteroids and calcineurin inhibitor (CNI) and the predictive factors for ASS-ILD recurrence were examined. We retrospectively identified consecutive patients with ASS-ILD treated with corticosteroids and CNI during 2006–2017 and evaluated the predictive factors for recurrence using logistic regression analysis. Of the 57 patients included in this study, 54 (94.7%) exhibited improved response to remission induction therapy. There were 32 recurrence patients during maintenance therapy. The median period until recurrence was 27 months. There were no significant differences in the baseline characteristics between the recurrence and nonrecurrence groups. In the recurrence group, respiratory function and St. George's Respiratory Questionnaire score deteriorated over the clinical course. The Krebs von den Lungen-6 (KL-6) level changed with disease behavior. The multivariate analysis revealed that KL-6 increase rate from remission (odds ratio: 3.21, 95% CI: 1.17–8.86, p = 0.02) and CNI discontinuation (odds ratio: 8.09, 95% CI: 1.39–47.09, p = 0.02) were independent predictive factors for recurrence. The receiver operating characteristics analysis revealed that the optimal cut-off point of KL-6 increase rate was 2.0. The positive predictive values of the KL-6 increase rate from remission of >2.0 and CNI discontinuation were 90.0 and 88.9%, respectively. The CNI treatment duration and recurrence were not related. Recurrence influenced long-term deterioration. KL-6 was a serum biomarker for disease behavior and recurrence prediction. The results suggest the importance of CNI continuation.