Objectives: Immunoglobulin-G4-related disease (IgG4-RD) is a distinct systemic autoimmune-mediated disease manifesting as chronic inflammation and tissue fibrosis. Since the role of DNA methylation in the pathogenesis of IgG4-RD is still unclear, we conduct this study to investigate epigenetic modifications in IgG4-RD.
Methods: A genome-wide DNA methylation study was conducted with B cells, CD4+ T cells, and salivary gland tissues from IgG4-RD patients and matched controls by using the Illumina HumanMethylation 850K BeadChip. We further performed pyrosequencing and immunohistochemistry assays to validate the methylation status of some targets of interest.
Results: We identified differentially methylated CpG sites including 44 hypomethylated and 166 hypermethylated differentially methylated probes (DMPs) in B cells and 260 hypomethylated and 112 hypermethylated DMPs in CD4+ T cells from 10 IgG4-RD patients compared with 10 healthy controls. We also identified 36945 hypomethylated and 78380 hypermethylated DMPs in salivary gland tissues of 4 IgG4-RD patients compared with 4 controls. DPM2 (cg21181453), IQCK (cg10266221), and ABCC13 (cg05699681, cg04985582) were hypermethylated and MBP (cg18455083) was hypomethylated in B cells, CD4+ T cells, and salivary gland tissues of IgG4-RD patients. We also observed the hypomethylated HLA-DQB2 in CD4+ T cells from IgG4-RD patients. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DMPs in salivary gland tissues of IgG4-RD patients revealed enrichment of pathways involved in the regulation of immune cell responses and fibrosis.
Conclusion: This is the first DNA methylation study in peripheral B cells, CD4+ T cells, and salivary gland tissues from IgG4-RD patients. Our findings highlighted the role of epigenetic modification of DNA methylation and identified several genes and pathways possibly involved in IgG4-RD pathogenesis.
Keywords: B cells; CD4+ T cells; DNA methylation; IgG4-RD; Salivary gland tissues.
© 2023. The Author(s).