Using Urine to Study Antibodies & Functional Cell-Mediated Immunity in the Context of Chlamydia Trachomatis (URSAFE-CT)

To date, clinician-collected blood samples are still the primary methods to monitor immune responses to genital tract infections. Replacing these samples with a specimen that is non-invasive and can be self-collected, such as the initial or first-void urine stream or vaginal brushes, could have important acceptance and feasibility advantages and could facilitate the logistics of clinical trials and future epidemiological or vaccine studies. Moreover, these local samples give more information on the immune response at the site of infection, in the genital tract. Initial results of experiments using first-void urine samples and cervicovaginal brushes for immune response monitoring are promising. However, no standardized method for the detection of (functional) Chlamydia trachomatis (CT)-specific immune responses is available to be used on first-void urine or vaginal samples. Therefore, the aim of this pilot study is to determine feasibility to detect mucosal immune responses in first-void urine and self-collected vaginal samples. Furthermore, we will compare local immune responses with systemic immunity.

The primary objectives of this study are:

• To explore the feasibility to detect (functional) CT-specific antibodies and CT-specific cellular immune responses in first-void urine or self-collected vaginal samples.
• To compare levels of total and CT-specific antibodies in first-void urine and serum.
• To compare mucosal and systemic CT-specific cellular immune responses in mucosal mononuclear cells derived from first-void urine or self-collected vaginal samples, and peripheral blood mononuclear cells (PBMCs).

A total of 73 female participants will be included in this trial. Women that can be included have to be positive for a Chlamydia trachomatis nuclear acid amplification test (NAAT) on a vaginal or FVU sample, and have not yet been treated with antibiotic therapy.

The study described is a low-interventional observational study. Participants will self-collect a first-void urine sample using a 20 mL Colli Pee® device (Novosanis), followed by a vaginal brush (Evalyn® brush, Rovers). Medical personnel at the study site will collect a blood sample (one serum tube and 2 heparin tubes). Furthermore, personal data is collected via a paper-based questionnaire.