TO008COMPARATIVE TRANSCRIPTOME AND CO-EXPRESSION NETWORK ANALYSIS REVEALED A POTENTIAL ROLE OF C1QB AND INTERFERON TYPE 1 PATHWAY IN CIRCULATING IMMUNE CELLS OF KIDNEY TRANSPLANTS PATIENTS WITH CHRONIC ANTIBODY MEDIATED REJECTION
Abstract Background and Aims Chronic antibody-mediated rejection (CAMR) is a multifactorial pathological condition that can affect more that 40-50% of kidney allografts. Its clinical evolution is often silent, and this can delay its diagnosis. Although many advances in understanding the biological mechanisms underlying its onset/development, at the moment, no reliable non-invasive diagnostic biomarkers are available in clinic. Method We enrolled 29 patients with biopsy-proven CAMR, 29 stable transplant recipients (controls). Subsequently, the microarray profile of mRNA isolated from peripheral blood mononuclear cells (PBMCs) from 10 randomly selected CAMR patients and 10 controls was evaluated by Agilent technology. For the bioinformatics analysis we employed several statistical algorithms (including ANOVA and Kruskal-Wallis tests adjusted for multiple-tests) and a Weighted Gene Correlation Network Analysis (WGCNA) to select genes biologically associated in co-expressed networks. Results 935 genes resulted differentially expressed between the two study groups, demonstrating the large biological impact of this pathological condition on circulating immune-inflammatory cells. After WGCNA co-expression analysis, a group of genes (enclosed in a single co-expression module, 13 genes) resulted highly discriminating CAMR versus controls (p<.5.2 e-7, FDR<1%). This module included: Interferon-induced transmembrane proteins (IFITM) 2, 3, 4, confirming previous results by our group. However, the top discriminative gene was C1QB (Complement component 1, q subcomponent, B chain, p <000.1), a key element involved in the classical complement pathway. ELISA confirmed the microarray results on the entire patients’ cohort. Conclusion Our study confirmed the role of the type 1 interferon pathway in CAMR and underlined its capability to promote C1QB expression. These effects could contribute to better define the role of innate immunity in CAMR. Finally, C1QB, if validated in a large cohort of patients, could represent a new valuable molecular diagnostic biomarker for this complication.