Immunological Studies of Reactive Oxygen Species Damaged Catalase in Patients with Systemic Lupus Erythematosus: Correlation with Disease Activity Index

Abstract

Objectives: This study was undertaken to investigate the status and contribution of oxidized catalase in systemic lupus erythematosus (SLE) and to explore whether oxidized catalase has a role in disease progression. Methods: Catalase (CAT) was modified by reactive oxygen species (ROS). Sera from 50 SLE patients with varying levels of disease activity according to SLE Disease-Activity-Index (SLEDAI) and 45 age- and sex-matched healthy controls were evaluated for antibodies against oxidized CAT. Results: Serum analysis showed significantly higher level of anti-oxidized-CAT-antibodies in SLE patients compared with controls. Interestingly, not only was there an increased number of subjects positive for anti-oxidized-CAT-antibodies, but also the levels of these antibodies were significantly higher among SLE patients, whose SLEDAI scores were ≥10 as compared with lower SLEDAI scores (<10). In addition, significant correlation was observed between the levels of anti-oxidized-CAT-antibodies and SLEDAI score (r = 0.796). Furthermore, sera from SLE patients had lower levels of CAT activity compared with control sera. Conclusions: These findings support an association between oxidized CAT and SLE. The stronger response observed in serum samples from patients with higher SLEDAI scores suggests that oxidized CAT may be a useful biomarker in evaluating the progression of SLE and in elucidating the mechanisms of disease pathogenesis.

• Oxidized catalase
• SLE
• SLEDAI
• Anti-ROS-CAT antibodies

ACKNOWLEDGEMENTS

This work was supported by Qassim University Research Deanship Grants SR-D-011-952 and SR-D-012-1298 and funds from College of Medicine, Qassim University. Authors also thank Professor A. Alghasham (Dean, College of Medicine) for providing research facilities.

HAA, AAR, AAA carried out the experimental work, data collection, interpretation and manuscript drafting. ZR conceived of the study, its design, experimentation, coordinated, data interpretation and manuscript drafting.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.