The Diagnostic Discriminative Power of Serum IL-6 Levels for Chlamydia Trachomatis Infection

Abstract

Background: Chlamydia trachomatis is one of the most common sexually transmitted bacterial pathogens and often asymptomatic but can cause negative consequences, including infertility. Identifying robust biomarkers has been highlighted as necessary for improving early detection strategies. Aim: The aim of this study was to assess the possible usefulness of circulating interleukin-6 (IL-6) levels in the diagnosis of Chlamydia trachomatis infection. Methods: A case–control study with 52 cases of laboratory-confirmed C. trachomatis infection and 48 apparently healthy controls was conducted. We measured serum IL-6 levels by ELISA. Independent samples t-tests were performed for between-group differences and analysis of variance (ANOVA) was used to analyze site differences regarding the factors associated with improving quality of life. Furthermore, the ability of IL-6 to differentiate between infected and non-infected subjects was assessed by receiver operating characteristic (ROC) curve analysis. Results: The IL-6 levels were significantly higher in patients (18.6 ± 5.2 pg/ml) than those in controls (12.4 ± 4.1 pg/ml, p < 0.03). We also determined serum IL-6 levels by anatomical infection sites showing that they were the highest in urogenital infections (19.2 ± 5.1 pg/ml) and moderately lower for rectal infections (17.5 ± 4.6 pg/ml). The area under the curve (AUC) was 0.84, with an ideal diagnostic threshold set at 15.5 pg/ml, with a sensitivity of 80.8% and specificity of77.1%. Conclusions: These results indicate that the levels of IL-6 is significantly higher in those infected with Chlamydia trachomatis, which suggests as a potential monitoring biomarker at sites of urogenital infection.

Keywords:

Specificity, Sensitivity, AUC, Chlamydia trachomatis, Interleukin-6

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