Chlamydia trachomatis antibody test in vaginal swabs as an intermediate marker for PID and tubal pathology - pilot study in fertility clinics

Chlamydia trachomatis (Ct) is a common sexually transmitted infection among
adolescents. In women lower genital tract infections (cervicitis) may ascend to
the upper genital tract and cause Pelvic Inflammatory Disease (PID), which may
lead to tubal pathology and subsequent infertility. Chlamydia cervicitis and
PID often remain asymptomatic, which makes treatment and prevention of late
sequelae difficult. Furthermore, it may take a decade or more before late
complications (infertility) become evident, and for diagnosing tubal pathology
an invasive and costly procedure (i.e. laparoscopy) is required. An
intermediate, non-invasive biomarker that could predict late complications of
Ct infection would enable identification of women at high risk for
complications and facilitate effect evaluation of interventions aimed at
reduction of the prevalence of complications of Chlamydia.
It has been known for many decades that in infertile women tubal pathology is
associated with the presence of Chlamydia IgG antibodies in serum. In fertility
clinics, the Chlamydia IgG Antibody test (CAT) in serum (serum-CAT) is used as
a screening test for tubal pathology, and for selecting high risk patients for
laparoscopy. So far it has not been studied whether CAT can be tested by
alternative non-invasive means, i.e. in self collected vaginal swabs of mucosa
instead of in serum.

We will investigate whether Chlamydia IgG antibody presence and titers in
vaginal swabs (mucosa-CAT) are comparable to antibodies found in serum
(serum-CAT), and as such could serve as a marker for a past Chlamydia infection
with an enhanced risk of complications.

Comparative diagnostic study, comparing already available results of serum-CAT
with results of mucosa-CAT in women attending the fertility clinics of the
University Medical Centers in Groningen and Maastricht. Recruitment will
continue until a number of 25 serum-CAT positive and 50 serum-CAT negative
women is reached. The partcicipants will be asked to respond to a short
questionnaire and collect a vaginal self-swab.

Eligible patients will receive a written request to participate. After consent
is given, they receive a short questionnaire on past Chlamydia infections and
PID and a test-kit with a vaginal swab for self-collection which can be
returned by mail. There are no risks for the participating women, and for them
there are no direct, individual benefits.