Autoimmune diseases, such as type 1 diabetes (T1D) and Hashimoto's thyroiditis (HT), are often studied from an immune perspective with less focus on the target tissue responses. Target tissues, however, are key to disease and engage in a harmful crosstalk with the immune system contributing to their own destruction. We presently integrated transcriptomic data from the target tissues of six autoimmune/inflammatory diseases affecting β-cells (T1D and type 2 diabetes), thyroid (HT), brain (multiple sclerosis and Alzheimer's disease) or the joints (rheumatoid arthritis), using both bulk and single-cell/nucleus RNA-sequencing (sc/snRNA-seq) approaches. Common upregulated pathways were associated with innate/adaptive immunity, antigen presentation and interferon (IFN) signaling. The role of IFNs was confirmed by RNA-seq in human insulin-producing EndoC-βH1 cells and stem cell-derived thyroid follicle cells exposed to IFNα or IFNγ. Commonly upregulated inflammatory gene signatures were explored, and fibroblast growth factor receptor (FGFR) inhibitors emerged as a potential strategy to counteract these inflammatory transcriptional signatures. The effects of the FGFR1 inhibitor PD173074 on IFN-induced immune related genes were evaluated in EndoC-βH1 cells, stem cell-derived islets and adult human islets. We validated the FGFR inhibitor PD173074 as a promising drug for preserving expression of β-cell protective genes (PDL1 and HLA-E) while reducing HLA class I expression and β-cell recognition by diabetogenic pre-proinsulin-specific CD8+ T-cells. In conclusion, we integrated transcriptomic data from the target tissues of autoimmune and inflammatory/degenerative diseases and departing from these data identified the potential beneficial effects of FGFR inhibitors in T1D.
Background: Interstitial lung disease (ILD) is associated with morbidity and mortality in idiopathic inflammatory myopathies (IIM). Predicting ILD progression remains a significant challenge, as conventional diagnostic tools such as pulmonary function tests (PFTs) and high-resolution computed tomography (HRCT) have limited prognostic accuracy. This study evaluated whether 68Ga-labelled inhibitor of Fibroblast-Activation-Protein (FAPI) based PET/CT at baseline predicts ILD evolution over two years.
Material and methods: In this prospective observational study, n = 19 individuals with IIM (n = 14 with ILD) underwent [68Ga] Ga-FAPI PET/CT at baseline. ILD progression was defined by three criteria: (1) FVC decline ≥10 % or FVC 5-9 % plus DLCO decline ≥15 %, (2) INBUILD criteria, and (3) a composite endpoint including INBUILD plus therapy escalation, hospitalization, or mortality. Pulmonary tracer uptake was quantified by calculating the maximum and mean target-to-background ratios across the whole lung (wlTBRmax and wlTBRmean, respectively), derived from standardized uptake values corrected for blood pool activity, and their predictive value was analysed.
Results: Over two years, n = 4 (28.6 %) patients met PFT-based progression criteria, while n = 6 (42.9 %) fulfilled INBUILD criteria, and n = 8 (57.1 %) reached the composite endpoint. Baseline wlTBRmax was significantly higher in INBUILD progressors compared to non-progressors (2.68 ± 1.06 vs. 1.59 ± 0.80, p = 0.04), as was wlTBRmean (0.58 ± 0.22 vs. 0.34 ± 0.10, p = 0.04). Similarly, patients meeting the composite endpoint had higher wlTBRmax (2.63 ± 1.04 vs. 1.30 ± 0.31; p < 0.01) and wlTBRmean (0.55 ± 0.20 vs. 0.31 ± 0.09; p = 0.01). Logistic regression analysis showed that incorporating pulmonary wlTBRmax and wlTBRmean enhanced the predictive accuracy over PFT and HRCT alone.
Conclusion: FAPI PET/CT may serve as a non-invasive biomarker for early prediction of ILD progression in IIM, supporting personalized disease management. However, given the small, single-centre cohort, these findings should be considered as preliminary and require validation in larger, multi-centre studies.

