Circulating Cell-Free DNA as Inflammatory Marker in Egyptian Psoriasis Patients

BACKGROUND: Cell lesion and apoptosis with release of cell-free DNA (CFD) in circulation are associated with chronic inflammation of psoriasis. OBJECTIVE: The objective of this study was to determine the CFD concentrations in sera of patients with psoriasis, to assess its relationship with disease severity as defined by Psoriasis Area Severity Index (PASI) and other inflammatory biomarkers (C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)) levels, and to monitor the efficacy of treatment. PATIENTS AND METHODS: Thirty adult patients with different types of psoriasis (25 vulgaris; 10 mild, 15 moderate and 5 erythroderma; severe) were evaluated during the exacerbation phase of the disease, before starting (T0) and after 12 weeks (T12) of treatment with topical therapy for mild cases, narrowband-ultraviolet light B (NB-UVB) for moderate cases and methotrexate for severe cases. Twenty healthy controls were also involved in the study. The concentrations of CFD in sera were measured before and after treatment by quantitative real time PCR (qPCR) using primers of the human β-globin gene. RESULTS: At T0, all patients presented significant higher levels of ESR (P=0.05) and CFD (P=0.001) compared with controls. Highly significant elevations of all parameters were observed in severe disease (erythroderma) compared to mild/moderate disease (vulgaris). Methotrexate treatment induced highly significant reductions in all inflammatory markers including CFD (P= 0.042) while topical and UV irradiation therapies had no effects. CFD concentrations showed positive correlations with both PASI (r=0.422, P=0.020) and ESR (r=0.321, P=0.023) only before the start of treatment. CONCLUSION: The level of circulating CFD could be used to monitor psoriasis severity. However, its level cannot be stated for the treatment, except in severe erythrodermic patients upon successful treatment with methotrexate. We recommend validation of a convenient and accurate DNA assay applied directly to biological samples which does not require prior DNA extraction and amplification.