Comparison of serum C3 complement levels between young women with recurrent urinary tract infection and healthy women

Background: C3 complement plays a pivotal role in the complement cascade, subserves several critical functions in human immune response and enhancing bacterial killing and its levels correlate with infectious diseases. However, the association of C3 with recurrent urinary tract infection (UTI) is still debatable. Aim: The aim of this study was to assess the correlation of serum C3 levels and recurrent UTI among young women. Materials and methods: Thirty-four recurrent UTI patients whose diagnosed based on Society of Obstetricians and Gynecologists of Canada and European Association of Urology criteria and 34 healthy young women, aged 15–50 years old, were included in this study. Risk factors and clinical manifestations were evaluated and serum C3 levels were measured by ELISA. Correlations of risk factors, clinical manifestation and C3 levels with recurrent UTI were analyzed with chi-square test and Fisher’s exact test or t-test as appropriate with data. Results: This study found that some risk factors (age [p = 0.000], sexual intercourse frequency [p = 0.00], marital status [p = 0.000] and intrauterine device contraception [p = 0.000]) and clinical manifestations (fever [p = 0.000], dysuria [p = 0.000], frequent urination [p = 0.000], supra-pubic discomfort [p = 0.000] and flank pain [p = 0.006]) were correlated with recurrent UTI. Although this study found that serum C3 levels were significantly different between recurrent UTI patients and healthy young women group (mean 42.08 μg/ml ± 1.20 vs 42.75 μg/ml ± 0.71, p = 0.008), this difference is not clinically relevant. Conclusion: In this study setting, the levels of C3 among young women with recurrent UTI were lower than healthy women but were not significant clinically