Soluble Human Leukocyte Antigen-G Expression In Pregnancy Success And Early Pregnancy Loss In Korle-Bu Teaching Hospital

ABSTRACT

Background: Human Leukocyte Antigen (HLA) -G is a non-classical major histocompatibility complex (MHC) class I protein which has been described as being selectively expressed on the invasive trophoblast at the materno-foetal interface at the beginning of pregnancy. HLA-G has the potential role of protecting the trophoblast from cytotoxicity and enhancing maternal acceptance of the semi-allogeneic foetus by modulating the maternal immune system. HLA-G exerts several immunomodulatory effects, being beneficially implicated in embryo implantation and foetal survival. HLA-G inhibits the activation of the immune cells, and primes them into cytokine secretion profiles to control trophoblast invasion and maintain a local immunosuppressive environment for successful implantation and pregnancy survival. HLA-G has the ability to modulate the release of cytokines from human allogeneic peripheral blood mononuclear cells, and generate allogeneic cytotoxic T lymphocytes (CTLs) response in a concentration-dependent manner. Soluble isoforms of HLA-G has also been demonstrated to inhibit trophoblast invasion of the maternal decidua.

Setting/Location: The study was conducted at the Department of Obstetrics and Gynaecology in the Korle-Bu Teaching Hospital. Korle-Bu Teaching Hospital is a leading teaching hospital and a major referral centre in Ghana.

Aim: The aim of the study was to determine the role of soluble HLA-G in pregnancy success and early pregnancy loss in Korle-Bu Teaching Hospital.

Methods: This study involved eighty participants made up of twenty eight (28) normal pregnant women who had normal delivery, thirty two (32) women who had spontaneous or recurrent abortion, ten non-pregnant women and ten healthy men. A semi-structured questionnaire was administered to each consented participant to document their sociodemographic characteristics, and the history of pregnancy was

obtained from the clinic folders. 5ml of venous blood samples were collected from each consented participant and the plasma used to determine sHLA-G levels by Enzyme-linked immunosorbent assay (ELISA).

Results: The median sHLA-G levels were higher among women who had spontaneous abortions (66.5 U/ml) as compared to pregnant women who had normal delivery (49.53 U/ml), this was statistically significant. The first and second trimester sHLA-G levels of women who had spontaneous abortion are 66.53U/ml and 74.08U/ml respectively and was not statistically significant. The first and second trimester sHLA-G levels of pregnant women who had normal delivery are 39.73U/ml and 69.06U/ml respectively and were also not statistically significant. Healthy males had sHLA-G level (79.11 U/ml) as compared to healthy non-pregnant women (58.28 U/ml) but the difference was not statistically significant. Maternal sHLA-G levels was not statistically significant (P=0.26) in relation to maternal age and birth weight (P=0.38).

Conclusion: The results indicate that high levels of sHLA-G may adversely affect pregnancy outcome whilst reduced sHLA-G expressions may enhance pregnancy survival. There was not a significance difference between gestation and sHLA-G levels of women who had spontaneous abortion and normal pregnancy in pregnant women who had normal delivery. The sHLA-G levels were not affected by gender; healthy males had higher sHLA-G level as compared to healthy non-pregnant women, who were all in normal conditions of health but the difference was not statistically significant. This suggests that high sHLA-G levels in healthy individual may play a role in immunosurveilance. The history of contraceptive use had no effect on sHLA-G levels of women who had spontaneous abortion. Finally, there was no relationship between maternal age and corresponding sHLA-G levels, which had no effect on infant birth weight.