Pulmonary histopathology of interstitial lung disease associated with antisynthetase antibodies

Background: We aimed to determine if antibody type is an indicator of pulmonary histopathology, using antisynthetase antibody positive interstitial lung disease (ILD) cases with lung biopsy or autopsy findings. Methods: We conducted a comprehensive review of the English language literature in PubMed to identify ILD histopathology results for cases with antibodies against anti-aminoacyl-transfer RNA (tRNA) synthetases (antiARS antibodies), including Jo1, PL-12, PL-7, KS, ES, and OJ. We additionally identified patients who had ILD, anti-ARS antibodies, and a lung biopsy between 2015 and 2020 at Beth Israel Deaconess Medical Center. For each case, we documented the specific anti-ARS antibody and major histopathologic patterns identified on biopsy or autopsy, including usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), organizing pneumonia (OP), and acute lung injury (ALI). To determine if histopathology varied by antibody type, we compared the proportion of each of four major patterns by antibody type using the Fisher's Exact test. Results: We identified 310 cases with pathology findings and anti-ARS antibody positivity, including 12 cases from our institution. The proportion of NSIP differed significantly across antibody type, found in 31% of Jo1 (p < 0.01), 67% of EJ (p < 0.01), and 63% of KS (p < 0.01) cases. OP was common in Jo1 (23%, p = 0.07), but rare in EJ (4%, p = 0.04) and KS (4%, p = 0.04). UIP was common in PL-12 alone (36%, p = 0.03). Conclusion: The frequency of histopathologic findings in ILD with anti-ARS positivity varies significantly by antibody type, and NSIP occurs in less than half of all cases.