Decreased DNA hydroxymethylation and increased DNA demethylation are associated with high antioxidant response in systemic lupus erythematosus patients.

Abstract Objectives DNA hydroxymethylation may be induced by oxidative stress in lupus patients, so we investigated the association between DNA hydroxymethylation and demethylation with the antioxidant response. Methods A case–control study was performed including lupus patients and matched healthy controls. Serum concentration of glutathione (GSH), glutathione disulphide (GSSG), superoxide dismutase (SOD) and total antioxidant capacity (TAC), 5-mC and 5-hmC were determined. Results One hundred and forty-two patients and 34 controls were included. 5-hmC levels were lower in SLE patients than in controls. GSH and GSSG values were lower in patients, while SOD levels were higher in patients. TAC did not show significant differences, but higher demethylation and lower hydroxydemethylation were associated to increased TAC values. Lower demethylation was associated with cytopenia and lower hydroxymethylation with longer course of the disease. Lower levels of GSH and GSSG and higher SOD values were associated with accumulated damage assessed by SLICC-ACR. Conclusions Lower hydroxymethylation in patients than in controls was observed. Moreover, higher demethylation and lower hydroxymethylation leads to high TAC levels. DNA hydroxymethylation seems to be related to longer course of the disease.