Cd3+cd4-cd8-Double Negative T-cells Are Involved In Unexplained Infertility And Recurrent Reproductive Failure

Objective: Recurrent spontaneous abortion(RSA)and recurrent implantation failure(RIF)are now collectively referred to clinically as recurrent reproductive failure(RRF).There are many causes of Infertility and RRF,but there are still a large number of women who are still undiagnosed after routine screening.And in recent years,immunological factors have received increasing attention from clinical practitioners.It is generally accepted that most early pregnancy losses are associated with immune tolerance imbalance due to abnormal immune regulation at the maternal-fetal interface,and patients with pregnancy loss have a Th1/Th2 imbalance in their bodies,with a shift towards Th1.In addition,CD3+CD4-CD8-double negative T lymphocytes(DNT cells)have the function of down-regulating and alloimmune responses.But few reports have been published on DNT cells in patients with unexplained infertility and RRF.Here,we aimed to assess the effect of peripheral DNT cells in patients with unexplained infertility and RRF.Methods: This is a single-center,retrospective,propensity-score-matched study collecting normal women of childbearing age and patients with unexplained infertility and RRF attending the Affiliated Hospital of Guilin Medical College from 2020.1.1 to 2021.12.30.Sixty-eight healthy infertile women,238 infertility patients,and 109 RRF patients were included.Baseline characteristics(age,thyroid autoantibody,antinuclear antibodies,anti-β2 glycoprotein I antibody,etc.)were balanced using propensity-matched analysis,matching patients groups with healthy controls,comparing the differences in peripheral blood DNT cells between normal women of childbearing age and patients,and plotting the receiver operating characteristic(ROC)curve of peripheral blood DNT cells.Spearman correlation analysis and linear regression analysis were used to explore the factors responsible for the elevated percentage of DNT cells.Further,based on pregnancy outcomes,patients with successful(n=62)and failed(n=27)pregnancies were screened for matched analysis to explore the effect of peripheral blood DNT lymphocyte and prednisone acetate usage rate on pregnancy outcomes.Results:(1)Baseline patient characteristics were used as covariates for propensity scores with a matching capacity of 0.02,and 101 patients were matched successfully in each group.After matching,Infertility: RRF= 33(30,37):5.21(3.3,8.28),P=0.577>0.05.(2)Baseline characteristics of all populations included were used as covariates for propensity scores with a matching capacity of 0.02,and 62 people were successfully matched in each group.After matching,Control group: Case group = 3.26(2.40,5.56): 5.37(3.68,8.04),P<0.001,with a statistically significant difference in peripheral blood DNT lymphocytes between the two groups.(3)The area under the ROC curve of peripheral blood DNT lymphocytes was 0.711(95% CI 0.621-0.802,P<0.001),with a cut-off point of3.59 or 3.66.(4)The association between age,thyroid antibodies,antinuclear antibodies,anti-β2 glycoprotein I antibodies and peripheral blood DNT lymphocytes was analyzed using Spearman’s correlation,P>0.05,with not statistically significant.(5)The association between T lymphocytes(%),B lymphocytes(%),NK lymphocytes(%),CD4+ lymphocytes(%)and peripheral blood DNT lymphocytes was analyzed using Spearman correlation,and the correlation coefficients were between 0.2-0.4(P<0.05),while CD8+ lymphocytes(%),CD4+CD8+ lymphocytes(%),IL-4 content,IL-10 content,IL-17 content,INF-γcontent,and TNF-α content were not significantly associated with peripheral blood DNT lymphocytes(P>0.05).(6)Baseline characteristics were used as covariates for propensity scores with a matching capacity of 0.02,and 12 patients were finally matched in each group.After propensity-matched analysis,there was not a statistically significant difference between two groups in pre-treatment peripheral blood DNT lymphocytes by pregnancy outcome(Failure group: Success group,P=0.204>0.05,ATT=0.845>0.05).(7)Baseline characteristics were used as covariates for propensity scores with a matching capacity of 0.02,and 20 women were finally matched in each group.The use of prednisone acetate had no significant effect on pregnancy outcome(Failure group: Success group,P=0.932>0.05,ATT=0.583>0.05).(8)In the peripheral blood of some patients,DNT lymphocyte subsets contained Natural killer(NK)-like T lymphocytes.Conclusions: The peripheral DNT lymphocytes in patients with unexplained infertility and RRF is significantly higher in normal women of,with an area under the ROC curve of 0.711 and a cut-off point of 3.59 or 3.66.However,elevated peripheral DNT lymphocyte is not associated with thyroid antibodies,antinuclear antibodies,anti-β2 glycoprotein I antibodies,other lymphocytes or Th1/Th2/Th17 cytokine.And DNT lymphocytes seems to have not impact on pregnancy outcome.In addition,there was no significant improvement in pregnancy outcome in patients with unexplained infertility and RRF with additional prednisone compared to conventional treatment.