THU0240 GENE EXPRESSION SIGNATURES ARE RELATED TO SPECIFIC SUBSETS OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Abstract

Background: Systemic lupus erythematosus (SLE) is a heterogeneous, lifelong autoimmune disease, with a more severe phenotype in children compared to adult-onset SLE [1]. To date, approved drugs are by far not effective enough and have significant side effects, especially due to the use of prednisone. Although profiling of the blood transcriptome revealed a prevalent IFN type I signature in SLE, blocking the IFN pathway only showed efficacy in a subset of adult-onset SLE patients. Recent studies revealed that other gene signatures like IFN type I+II (M5.12), B cell, plasmablast and neutrophil signatures are important in SLE as well and some could be linked to specific clinical phenotypes [2, 3]. Assessment of these novel gene signatures in SLE may help to distinguish specific disease phenotypes and guide treatment choices in the future. Objectives: To determine and compare the expression of the IFN-, B cell-, plasmablast- and neutrophil signatures in pediatric and adult SLE patients. Methods: The IFN-I-, M5.12-, neutrophil-, B cell- and plasmablast signatures were measured using real-time quantitative PCR expression on whole blood RNA samples. To identify correlated groups of genes and reduce data complexity, the expression of a selection of genes identified by blood transcriptional profiling was tested and subsequently added to a principle component analysis to obtain a limited set of genes (2-5 per signatures), that reliably represent a specific signature. These signatures were analyzed in three separate pilot cohorts of healthy controls (n=12), pediatric- (n=22; average disease duration=0.9 years) and adult SLE patients (n=36; average disease duration=17.4 years). Results: IFN-I signature was significantly higher in SLE patients compared to healthy controls (p=0.001). M5.12 (p=0.05) and the B cell (p=0.0001) signature showed a significant difference between the pediatric and adult cohort while there was no difference between the neutrophil- and plasmablast signatures in the two patient groups. Interestingly, the B cell gene signature, correlated with age (p=0.0001, r= -0.49) and disease duration (p=0.001, r= -0.42). In addition, the possible correlation between the IFN-I signature and the other signatures was investigated. While the IFN-I signature in both adults and children showed a significant positive correlation to the M5.12- (p Conclusion: In this pilot study we found significant differences in gene expression signatures between pediatric and adult SLE patients. Additionally, age and disease duration were significantly correlated to the B cell gene signature. These findings indicate differences in transcriptional profiles in specific subsets of SLE patients which could have therapeutic consequences.