Whole blood global DNA methylation [5-methylcytosine (5-mC)] levels in psoriatic patients before and after methotrexate treatment

Psoriasis is a chronic inflammatory skin disease characterised by hyperproliferation of keratinocytes and abnormal immune response. It manifests in genetically predisposed individuals exposed to environmental triggers like infections, drugs, stress, and trauma. Epigenetic mechanisms are a critical component of the complex etiopathogenesis of psoriasis, as they modulate gene expression and increase disease risk. There are many conflicting reports regarding DNA methylation in patients with psoriasis. This could well reflect the choice of tissue and technique used. Data on whole blood DNA methylation in psoriasis is sparse. The present study aims to measure the levels of DNA methylation [5-methylcytosine (5-mC)] in psoriatic patients from whole blood pre and post-treatment with methotrexate and its correlation with disease severity. We recruited thirty cases of psoriasis vulgaris and 30 healthy controls. Thirty psoriatic patients were on methotrexate treatment and followed up for three months. 5-methylcytosine was measured using a global DNA methylation ELISA kit. The 5-methylcytosine levels from whole blood DNA were 8.13±1.89 % in cases and 5.37±2.33 % in controls, which was statistically significant (p = 0.0001). Post-treatment with methotrexate, there was a significant reduction (p = 0.0001) in the 5-methylcytosine levels in cases (4.54±1.74 %). Pre and post-treatment 5-methylcytosine levels were not significantly associated with the Psoriasis Area Severity Index (PASI) score. Patients with psoriasis have whole-blood DNA global hypermethylation. Treatment with methotrexate leads to a significant reduction in DNA hypermethylation. •The epigenetic factors are involved in the pathogenesis of psoriasis.•Psoriatics have whole blood global DNA hypermethylation.•Methotrexate significantly reduces whole blood DNA hypermethylation.