Immunoglobulin levels and phagocytes in the cervical mucus plug at term of pregnancy

Abstract

Acta Obstet Gynecol Scand 2005; 84: 734-742. # Acta Obstet Gynecol Scand 84 2005Background. To characterize the potential for adaptive immune protection in cervical mucus plugs with respect to immunoglobulin isotypes and effector cells (phagocytes).Methods. Thirty-one cervical mucus plugs were collected from healthy women in labor at term. The cervical mucus plugs were allocated either to analysis of immunoglobulins by enzyme-linked immunosorbent assay (ELISA), gel chromatography and Western blotting (n ¼ 20) or to microscopical, including immunocytochemical, analyses. The levels of immunoglobulin in the plugs were compared to the levels in 10 samples of ovulatory cervical mucus from nonpregnant women. Results. In the cervical mucus plugs, levels of immunoglobulin G (IgG) [median 3270 mg/ mL (100-14 500)] and IgA [540 (22-2820)], but not IgM [30.5 (1.0-160)], were significantly elevated compared to cervical mucus from nonpregnant women (p < 0.02 for IgG and IgA). The IgG : IgA ratio in the plugs was also elevated (p < 0.02). The proportion of secretory immunoglobulin A (SIgA) relative to total IgA in the plugs ranged from 16 to 65% (n ¼ 5). IgA and IgG were largely intact. Microscopically, the vagina-proximal part of the cervical mucus plugs contained bacteria and was rich in cells, mainly phagocytes. Conversely, the uterine part contained few cells. Conclusion. The high immunoglobulin levels in combination with the presence of phagocytes suggest a potential for adaptive immune defense in the cervical mucus plug, which, together with innate immune factors, may act as an immunological gatekeeper protecting the fetomaternal unit against infection from the vagina.

Sterile intra-amniotic inflammation in asymptomatic patients with a sonographic short cervix: prevalence and clinical significance

“…Patients with a CL 15 mm had a higher rate of positive AF culture [26% (15/57)] than patients with a CL !15 mm [3.8% (13/344)] [220]. It is unclear if a short cervix leads to compromised innate immunity following the loss of the anti-microbial properties of the cervical mucus plug [224][225][226][227][228][229] and predisposes to ascending intra-amniotic infection, or alternatively, if intra-amniotic infection leads to a short cervix.…”

Prevention of preterm birth: a randomized trial of vaginal compared with intramuscular progesterone

“…Several studies have demonstrated a number of actions that could contribute to prevention of PTB. These actions may be seen at the following four different levels: (i) reducing cervical stromal degradation (16), altering the barrier to ascending infection (17), inhibiting cervical ripening and improving cervical length in patients with a short cervix (18); (ii) decreasing the concentration of myometrial oxytocin receptors (19), reducing contraction frequency (13) and possibly acting as a tocolytic agent (20); (iii) attenuating the response to hemorrhage and inflammation in the decidua (21); and (iv) suppressing prostaglandin synthesis in fetal membranes and in the placenta, reducing apoptosis (21) and altering estrogen synthesis (22). Additionally, progesterone alters endocrine‐mediated effects in the fetus (22).…”

Effect of progesterone on cervical shortening in women at risk for preterm birth: secondary analysis from a multinational, randomized, double‐blind, placebo‐controlled trial

“…Two recent studies have demonstrated a reduction in the rate of preterm birth with intravaginal progesterone administration to women with premature cervical shortening3, 4. Progesterone is known to affect several cellular physiologies in each tissue of the reproductive tract including the cervix5–21.…”