DNA Methylation Signatures of Multiple Sclerosis Occur Independently of Known Genetic Risk and Are Primarily Attributed to B Cells and Monocytes
Alexandre Xavier, Vicki E. Maltby, Ewoud Ewing, Maria Pia Campagna, Sean M. Burnard, Jesper Tegnér, Mark Slee, Helmut Butzkueven, Ingrid Kockum, Lara Kular, Ausimmune/AusLong Investigators Group, Vilija Jokubaitis, Trevor J. Kilpatrick, Lars Alfredsson, Maja Jagodic, Anne‐Louise Ponsonby, Bruce Taylor, Rodney J. Scott, Rod A. Lea, Jeannette Lechner‐Scott
Abstract
Epigenetic mechanisms can regulate how DNA is expressed independently of sequence and are known to be associated with various diseases. Among those epigenetic mechanisms, DNA methylation (DNAm) is influenced by genotype and the environment, making it an important molecular interface for studying disease etiology and progression. In this study, we examined the whole blood DNA methylation profiles of a large group of people with (pw) multiple sclerosis (MS) compared to those of controls. We reveal that methylation differences in pwMS occur independently of known genetic risk loci and show that they more strongly differentiate disease (AUC = 0.85, 95% CI 0.82–0.89, p = 1.22 × 10−29) than known genetic risk loci (AUC = 0.72, 95% CI: 0.66–0.76, p = 9.07 × 10−17). We also show that methylation differences in MS occur predominantly in B cells and monocytes and indicate the involvement of cell-specific biological pathways. Overall, this study comprehensively characterizes the immune cell-specific epigenetic architecture of MS.