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.
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 SLEpatients 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 SLEpatients 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 SLEpatients, 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 SLEpatients 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.