The efficacy of transbronchial lung cryobiopsy for chronic progressive changes after remission of anti-MDA5 antibody-positive interstitial lung disease: a report of two cases.

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive interstitial lung disease (RP-ILD) may deteriorate even after remission with initial multidrug therapy. We report two cases of chronic progressive changes after remission. Transbronchial lung cryobiopsy (TBLC) identified distinct pathological processes: advanced fibrosis in one case and inflammatory relapse in the other, which directly guided therapeutic decisions. Rising antibody titers preceded deterioration in both cases. TBLC enabled accurate differentiation between relapse and fibrotic progression, emphasizing its utility in long-term management. Persistent serologic activity warrants close follow-up, and TBLC may aid in selecting individualized treatment strategies in post-remission deterioration.