P157 Potential benefit of intravenous immunoglobulin in connective tissue disease associated interstitial lung diseases
Authors: Kouranos Vasilis , Host Lauren V , Campochiaro Corrado , Wells Athol , Denton Christopher P , Ong Voon H , Renzoni Elisabeth 
Published: April 2021

Abstract
Background/Aims
Intravenous immunoglobulin (IVIg) confers significant benefit in range of connective tissue diseases (CTD) including inflammatory myopathy (IM) of which interstitial lung diseases (ILD) are a major complication. This study aimed to assess the efficacy of IVIg on pulmonary involvement in refractory active CTD including systemic sclerosis (SSc).
Methods
All patients with CTD-ILD confirmed on HRCT either with IM or SSc overlap myositis who did not achieve satisfactory clinical response to standard immunosuppressive agents and subsequently received regular IVIg infusions for IM were retrospectively identified. Serial lung function tests and immunosuppressive treatment regimen 9-12 months prior and 9-12 months after repeat courses of IVIg were recorded. Progressive ILD was considered when, despite immunosuppressive treatment, a relative FVC decline≥10% and/or relative DLco decline ≥15% were identified during the 9-12 months preceding IVIg treatment. The significance of median DLco and FVC percentage relative change to IVIg treatment was assessed by Wilcoxon signed-rank test.
Results
22 patients (mean age 50.5±13.1 years old) with IM-ILD treated with IVIg were identified. ILD occurred in association with IM in 10 patients, overlap SSc myositis in another 11 patients, while one had mixed connective tissue disease with myositis. Lung function results were available for 19/22 (86%). Eight patients (42.1%) were found to have progressive ILD(four with IM and four with overlap SSc-myositis). The median change in FVC% predicted and DLco% predicted in the 9-12 months before and after IVIg treatment is presented in Table 1. There was a significant difference in the DLco% predicted rate of relative change before and after IVIg treatment (p = 0.035) for the overall cohort. However, no differences in lung function were observed in the rate of relative change between patients with IM and patients with SSc myositis overlap. Significant improvement in DLco% predicted values was identified in the subgroup analysis of patients with progressive ILD(p = 0.012). P157 Table 1:The median change in FVC and DLco% predicted values prior and after the IVIg treatmentPatients with myositis related ILD9-12 months before IVIg treatment (relative change)9-12 months after IVIg treatment (relative change)p-valueAll (n = 19)FVC % predicted-3.8 (-54.4 - 14.6)2.1 (-33 - 33.7)0.145DLco % predicted-9.2 (-60.7 - 9.2)-2.3 (-26 - 41.9)0.035PM/DM (n = 10)FVC % predicted-1.8 (-20.2 - 14.6)0.8 (-33 - 30.9)0.401DLco % predicted-9.6 (-60.7 - 9.2)-2.4 (-26 - 41.9)0.093SSc-PM/DM overlap (n = 11)FVC % predicted-6 (-54.4 - 10.6)3.4 (-19.9 - 33.7)0.139DLco % predicted-10.8 (-47.1 - 2.5)4.2 (-22.7 - 16.8)0.173Progressive ILD (n = 8)FVC % predicted-14.5 (-54.4 - 14.6)5.7 (-11.9 - 33.7)0.123DLco % predicted-25.3 (-60.6 - -14.1)12 (-2.3 - 41.9)0.012
Conclusion
IVIg may be an effective rescue therapy in the prevention of further lung function decline in refractory myositis and SSc overlap in particular in subgroups with progressive ILD. Future studies to determine its role in CTD-ILD are warranted.
Disclosure
V. Kouranos: None. L.V. Host: None. C. Campochiaro: None. A. Wells: None. C.P. Denton: None. V.H. Ong: None. E. Renzoni: None.