Introduction: Human leukocyte antigen G (HLA-G) is a non-classical major histocompatibility complex
(MHC) class Ib antigen characterized by a limited polymorphism. The expression of HLA-G at
immune privileged sites and its ability to inhibit the effectors functions of immune cells has set
HLA-G as a molecule of immune tolerance. This expression pattern is unique among HLA genes
and suggests that HLA-G may be involved in interactions that are critical in establishing and/or
maintaining pregnancy. Methods: Soluble HLA-G (sHLA-G) levels were measured using a BioVendor
sHLA-G ELISA kit following the manufacturer’s protocol. The study participants include women
undergoing spontaneous abortion, non-pregnant women, males and an archive sample of
women who had normal vaginal deliveries without any complications and any history of malaria
infection from gestation to delivery. Results: Soluble HLA-G levels were higher among women undergoing
spontaneous abortion as compared to women who had normal vaginal delivery and
non-pregnant women. Soluble HLA-G levels were also higher in second trimester as compared to
first trimester in both women who had spontaneous abortions and women who had normal delivery.
Conclusion: Although sHLA-G levels were higher among women undergoing spontaneous
abortion as compared to non-pregnant women and women who had normal delivery, this may be
playing a role in the maintenance of maternal immune tolerance to fetal antigen, since plasma
sHLA-G levels increased with increasing trimester in both women who had normal delivery and
women undergoing spontaneous abortion.
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