114. Effects of tocilizumab on ex-vivo peripheral blood mononuclear cells from patients with GCA
Creators: name: Kamberovic1, Farah
name: Corbera-Bellalta1, Marc
name: Alba-Rovira1, Roser
name: Alba1, Marco
name: Marco-Hernández1, Javier
name: Prieto-Gonzalez1, Sergio
name: Espigol-Frigolé1, Georgina
name: Cid1, Maria C
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background:</strong> Giant –cell arteritis (GCA) is a chronic granulomatous vasculitis affecting individuals aged ≥50 years. Glucocorticoids (GCs) are only effective therapy able to induce disease remission but most patients relapse when GC are tapered and suffer from GC-related toxicity. Interleukin-6 (IL-6) is a pleiotropic cytokine that may play a pivotal role in GCA pathogenesis since its transcripts are increased in vascular lesions and elevated serum levels have been reported in active GCA patients. Recently, blocking IL-6 receptor with tocilizumab (TCZ) has demonstrated effectiveness in reducing GCA flares and sparing GC. However, 40% of patients still relapse when GCs are discontinued, indicating heterogeneity in TCZ-response. Therefore, identifying predictors of response to TCZ is crucial. TCZ strongly reduces systemic symptoand acute-phase reactants but little is known about the effects of TCZ on vascular lesions or peripheral blood mononuclear cells (PBMCs). The aim of this study was to investigate transcriptomic changes induced by IL-6 and TCZ+IL6 on <em>ex-vivo</em> PBMCs from patients in clinical remission. <strong>Methods:</strong> PBMCs were isolated from 17 patients in remission and 5 age and sex – matched controls using Lymphoprep™ density gradient. Fourteen patients were receiving prednisone (&lt;5mg/day) and 4 patients were in sustained remission without prednisone. PBMCs were exposed to recombinant human (rh) IL-6 (IL6 group) (20 ng/ml) and combination of rhIL-6 and TCZ (20 µg/ml) (TCZ+IL6 group) and cultured for 24h. Total RNA was extracted from cells using TRIzol™ reagent. RNA (100ng/sample) was processed using nCounter Prep Station screening for 256 genes from Human Inflammation Nanostring panel. Barcode counts were processed with nSolver 4.0 Software. Normalized data were analysed using R Studio 4.0.3 and paired or unpaired Wilcoxon tests were applied. <strong>Results:</strong> Total count of PBMCs was significantly lower in GCA compared to controls (1.26±0.43, 2.53±0.2 cell/ml, respectively; p&lt;0.0001). At transcriptomic level, 64 transcripts were differentially expressed between controls and patients, even considered in clinical remission; 5 transcripts were increased and 59 were decreased in GCA. After stimulation with IL-6, 12 transcripts were increased and 34 decreased respect to baseline condition. A total of 113 transcripts were differentially expressed between IL-6 group and TCZ+IL6 group. After correction for multiple comparisons, 73 transcripts remained significant (FDR&lt;0.05), of which 63 transcripts were increased with TCZ exposure. However, 8 transcripts that were increased with IL-6 stimulation, decreased their expression after exposure to TCZ: STAT3, HIF1A, CCL2, CCR1, BCL6, MYC, TLR2 and C3AR1; all of them being target genes of STAT3. <strong>Conclusions:</strong> Patients with GCA in clinical remission still have transcriptomic differences with healthy controls. Tocilizumab reduces expression of STAT3 and 7 other transcripts downstream from STAT3, important for differentiation of naïve T helper cells to follicular T helper cells (BCL6), cell growth/apoptosis (MYC), monocyte trafficking and activation (CCL2, CR1), activation of IL-6 (TLR2) and hypoxia (HIF1A). Validation is in process. Studies in active, treatment-naïve patients are ongoing. <strong>Disclosures:</strong> Marc Corbera- Bellalta, Farah Kamberovic, Roser Alba-Rovira, Marco A Alba, and Patricia Pérez-Galán have no disclosures to report. Georgina Espigol-Frigolé reports consulting for Janssen and Hoffmann-La Roche; meeting attendance suport from Boehringer Ingelheim. Sergio Prieto-Gonzalez reports lecturing for Roche; meeting attendance support from Italfarmo and CSL Behring. Maria C Cid reports a research grant from Kiniksa; consulting for Janssen, GSK, and Abbvie; educational grant from GSK and Vifor; meeting attendance support from Roche and Kiniksa. Funding received from EU Horizon 2020 research and innovation program (Marie Skłodowska-Curie grant agreement No. 813545), Spanish Ministry for Science and Innovation /AEI project No. PID2020-114909RB-I00, and the Vasculitis Foundation.