The Assessment of Dna Damage by Alkaline Comet Assay Is Not Associated With Clinical Outcomes in Women With Systemic Lupus Erythematosus

Abstract

Introduction: In systemic lupus erythematosus (SLE), an inflammatory state leads to oxidative stress and excessive formation of reactive oxygen species, increasing cellular damage, mutations and compromised DNA repair. Therefore, our study aimed to evaluate the performance of the alkaline comet assay to investigate DNA damage in women with SLE.Methods: This is a cross-sectional study that included Brazilian women with SLE attended at an university hospital (Rio de Janeiro, Brazil) from 2015 to 2018. Disease activity was assessed using the SLE Disease Activity Index 2000 (SLEDAI-2K). Diagnosis of CMVand EBV infections were performed by qPCR. DNA damage was determined by alkaline comet assay, which is a electrophoresis techinique used to evaluate DNA fragmentation in leukocytes, which is expressed as arbitrary units (AU). Results: We studied 34 SLE patients with a median age of 34.5 years-old. Hospitalized patients (n=11, 32.3%) presented higher SLEDAI-2K, where 9 (81.8%) had SLEDAI-2K ≥ 5 (p=0.038). We did not identify significant differences between healthy and SLE; however, hospitalized patients showed higher median AU, but with no statistical significance (p=0.095). Also, no differences were in DNA damage according to SLEDAI-2, lupus nephritis, use of immunossupressants, or CMV/EBV infections. DNA damage was not associated with levels of anti-dsDNA. Lastlty, ROC curves demonstrated a poor predictive power of DNA damage to differentiate groups (AUC < 0.7, p > 0,05). Conclusion: Our results indicate that DNA damage measured by alkaline comet assay is not associated with SLE severity and the presence of viral infections