Genome-wide DNA methylation profiles analysis in primary warm autoimmune hemolytic anemia patients

Background Autoimmune hemolytic anemia (AIHA) is caused by auto-antibodies, secreted by overactivated B cells, directed against self-red blood cells, resulting in hemolysis. It found that aberrant DNA methylation in B cells can induce the production of autoantibodies. Therefore, we attempted to explore if similar aberrant DNA methylation occur in AIHA patients. Methods A 49-year-old female wAIHA patient and a 47-year-old female healthy control (HC) were enrolled. Peripheral blood (PB) B cells DNA was extracted. After constructing genomic libraries, bisulfite genomic sequencing (BSP) and DNA methylation profiles were analyzed. BSP was verified using PB B cells from 10 patients with hemolysis, 10 patients with hemolytic remission, and 10 healthy controls (HCs) by Methylation-specific PCR. Results Total DNA methylation of whole-genome C bases (4.8%) and CG type bases (76.8%) in wAIHA patient were lower than those in the HC (5.3 and 82.5%, respectively) (p = 0.022 and p < 0.001). DNA methylation of C bases and CG type bases in whole-genome regulatory elements, such as coding sequence, up2Kb and down2Kb in the patient were also lower than those in the HC (p = 0.041, p = 0.038, and p = 0.029). 30,180 DNA-methylated regions (DMRs) on all 23 chromosomes were identified. DMR-related genes were mainly involved in the Rap1, phospholipase D, HIF-1, calcium, vascular endothelial growth factor (VEGF) and Ras signaling pathways. Conclusion The DNA methylation spectrum of B cells in AIHA patients is different from that of HC, and the proportion of hypo-methylation regions is higher than that of HC. DMR-related genes are mainly related to some signaling pathways.