Background.
Chlamydia infections often follow an asymptomatic course but may damage the reproductive tract. Chlamydia
antibodies in serum are used as markers for past
infections and can relate to tubal pathology and
infertility. This "proof of principle" study aimed to assess whether Chlamydia
antibodies are detectable in easier to obtain, noninvasive, vaginal mucosa samples and relate to current or past
infection. Methods. We compared outcomes of Chlamydia
IgG and
IgA antibody tests in serum and vaginal mucosal swabs in (a) 77 women attending a fertility clinic, of whom 25 tested positive for serum-
IgG and (b) 107 women visiting an
STI centre, including 30 Chlamydia PCR-positive subjects. Results. In the
STI clinic, active
Chlamydia infections were linked to serum-
IgG and serum-
IgA (P < 0.001) and mucosa-
IgA (P < 0.001), but not mucosa-
IgG. In the fertility clinic, mucosa-
IgG had stronger correlations with serum-
IgG (P = 0.02) than mucosa-
IgA (P = 0.06). Women with tubal pathology or Chlamydia history more commonly had serum-
IgG and mucosa-
IgA (both P < 0.001), whereas this link was weaker for mucosa-
IgG (P = 0.03). Conclusion. Chlamydia
IgG and
IgA are detectable in vaginal mucosal material. Serum-
IgG had stronger associations with current or past
infections. Mucosa-
IgA also showed associations with (past)
infection and complications.
IgA presence in vaginal mucosa warrants further epidemiological studies.