Global DNA methylation pattern and correlation with complement system proteins in Brazilian patients with systemic lupus erythematosus

Resumo

Introduction: Nucleic acid methylation may have major effects on gene expression patterns and, by consequence, on the development of autoimmunity, like Systemic Lupus Erythematosus (SLE). Objective: To investigate the pattern of global DNA methylation in SLE patients and compare this pattern with laboratory parameters. Methods: Genomic DNA was isolated from SLE patients with non-active disease (SLEDAI<6), SLE patients with active disease (SLEDAI>6), and healthy individuals. Global DNA methylation was evaluated by digestion of genomic DNA with HpaII and MspI and compared with laboratory parameters. Results and conclusion: A statistical difference in DNA global methylation was observed when SLE patients were compared to healthy individuals. A positive correlation was observed between the frequency of global methylation and C3 and C4 serum levels for SLE patients with SLEDAI<6. These results suggest that the relative amount of DNA methylation is increased in SLE patients, and differential methylation of genes related to the complement pathway alters gene expression involved in autoimmune response in SLE patients.