Angiotensin-converting enzyme (ACE) serum levels and gene polymorphism in Egyptian patients with systemic lupus erythematosus

Objectives: to investigate the association of angiotensin-converting enzyme (ACE) gene polymorphism and serum ACE level among Egyptian SLE patients and its relation to disease activity parameters. Subjects and methods: we enrolled 50 Egyptian female systemic lupus erythematosus (SLE) patients and 29 healthy controls. Measurement of serum ACE level was done using ELISA, and the ACE genotype was determined by polymerase chain reaction using genomic DNA from peripheral blood. Results: a significant difference was found in ACE genotypes between SLE patients and controls (χ2 = 7.84, p = 0.02). The frequency of ACE DD versus (DI and II) genotypes was significantly higher in SLE patients compared with controls (χ2 = 5.57, p = 0.018 and OR for risk of SLE was 3.1 with 95% confidence interval: 1.198.06). Mean serum ACE level was significantly higher in the SLE group compared with controls (p = 0.006). Subjects with DD genotype had a significantly higher mean level than those with DI (p = 0.015) and II genotypes (p = 0.02). Lupus nephritis patients had a significantly higher frequency of DD versus DI and II genotypes compared with lupus patients without nephritis (Fisher's exact test, p = 0.025) and controls (χ2 =8.74, p = 0.003). SLE patients with vasculopathy had a significantly higher frequency of DD versus DI/II genotypes compared with SLE patients without vasculopathy (Fisher's exact test, p = 0.04) and controls (χ2 = 9.84 and p = 0.002). Mean serum ACE level was significantly higher in the lupus nephritis and SLE patients with vasculopathy compared with controls (p = 0.008, p = 0.001, respectively). Significant positive correlations were found between serum ACE level and serum creatinine and 24 h proteinuria (p = 0.03, 0.009, respectively). SLE patients with DD genotype had a statistically significant higher mean SLEDAI score than those with (DI/II) genotypes (p = 0.02). Significant positive correlation was found between serum ACE levels and SLEDAI scores (p = 0.04). Conclusion: ACE genotype and subsequently serum ACE level could be associated with the disease activity of Egyptian SLE patients; in addition, ACE deletion polymorphism might be used as one of the predictive factors for the activity of SLE. Further studies on a larger number of patients should be done to determine the exact prevalence of ACE gene polymorphism among Egyptian SLE patients.