Intravenous Immunoglobulin in Acute Exacerbations of Fibrotic Interstitial Lung Diseases: A Retrospective, Real-World Study

<i>Background and Objectives</i>: Despite the devastating impact of acute exacerbations of fibrotic interstitial lung diseases (AE-fILDs), established treatment strategies are majorly lacking. The therapeutic potential of intravenous immunoglobulin (IVIG) in AE-fILDs was explored considering its anti-inflammatory and immunomodulatory effects, as well as the immunocompromised status of fILD patients and the high frequency of infections that AE-fILDs triggers. <i>Materials and Methods</i>: This was an observational, retrospective study. We investigated the therapeutic potential of IVIG in patients hospitalized for AE-fILDs between May 2021 and November 2024. <i>Results</i>: We included 39 patients diagnosed with AE-fILDs. All patients received IVIG (total dose of 1 g/kg, divided into three daily doses), pulse corticosteroids for three days and broad-spectrum antibiotics. No adverse events were considered to be related to IVIG therapy during the study period. The in-hospital and the 90-day mortality were 10 (26%) and 13 (33%) patients, respectively. Twenty-nine patients (74%) were discharged and 18 of them (62%) were in need of long-term oxygen therapy. The mean PaO₂/FiO₂ ratio (P/F ratio) was 183 mmHg on admission and 294 mmHg on discharge (<i>t</i>-test, <i>p</i> < 0.0001). <i>Conclusions</i>: This study suggests a potential therapeutic signal, indicating that IVIG is a relatively harmless, well-tolerated, and a potentially effective add-on treatment to current therapeutic approaches. Further research is essential to clarify the role of IVIG, determine optimal treatment protocols, and assess its efficacy in different ILD subtypes.