Serial changes in two immune checkpoint receptors and ligands, Tim-3/Gal-9 and PD-1/PD-L1 in peripheral blood prior to miscarriage: Comparison with pregnancies resulting in a live birth

Decreased serum soluble programmed cell death ligand-1 level as a potential biomarker for missed miscarriage

STUDY QUESTION

Can maternal serum levels of soluble programmed cell death-1 (sPD-1) and its ligand (sPD-L1) serve as biomarkers for missed miscarriage (MM)?

SUMMARY ANSWER

Serum sPD-L1 levels are significantly decreased in MM patients and may serve as a potential predictive biomarker for miscarriage.

WHAT IS KNOWN ALREADY

Programmed cell death-1 (PD-1) and its ligand (PD-L1) comprise important immune inhibitory checkpoint signaling to maintain pregnancy. Their soluble forms are detectable in human circulation and are associated with immunosuppression.

STUDY DESIGN, SIZE, DURATION

Three independent cohorts attending tertiary referral hospitals were studied. The first (discovery) cohort was cross-sectional and included MM patients and healthy pregnant (HP) women matched on BMI. The second validation cohort contained MM patients and women with legally induced abortion (IA). The third prospective observational study recruited subjects requiring IVF treatment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the discovery cohort, we enrolled 108 MM patients and 115 HP women who had a full-term pregnancy at 6-14 weeks of gestation. In the validation cohort, we recruited 25 MM patients and 25 women with IA. Blood samples were collected at the first prenatal visit for HP women or on the day of dilatation and curettage surgery (D&C) for MM and IA subjects to determine serum sPD-1 and sPD-L1 levels. Placenta samples were harvested during the D&C within the validation cohort to measure gene and protein expression. The prospective cohort collected serial blood samples weekly from 75 volunteers with embryo transfer (ET) after IVF.

MAIN RESULTS AND THE ROLE OF CHANCE

Circulating sPD-L1 levels were reduced by 50% in patients with MM (55.7 ± 16.04 pg/ml) compared to HP controls (106.7 ± 58.46 pg/ml, P < 0.001) and the difference remained significant after adjusting for maternal age and gestational age, whereas no significant differences in sPD-1 level were observed. Likewise, serum sPD-L1 was lower in MM patients than in IA subjects and accompanied by downregulated PD-L1-related gene expression levels in the placenta. In the IVF cohort, applying the changing rate of sPD-L1 level after ET achieved a predictive performance for miscarriage with receiver operating characteristics = 0.73 (95% CI: 0.57-0.88, P < 0.01).

LIMITATIONS, REASONS FOR CAUTION

The study was mainly confined to East Asian pregnant women. Further large prospective pregnancy cohorts are required to validate the predictive performance of sPD-L1 on miscarriage.

WIDER IMPLICATIONS OF THE FINDINGS

Reduced circulating sPD-L1 level and downregulated placental PD-L1 expression in miscarriage indicate that dysfunction in PD-L1 signals is a potential underlying mechanism for pregnancy loss. Our findings further extend the importance of the PD-L1 axis in pregnancy maintenance in early pregnancy.

STUDY FUNDING/COMPETING INTEREST(S)

This study was financially supported by grants from the Subject Innovation Team of Shaanxi University of Chinese Medicine (2019-Y502), General Research Fund (14122021), and Key Laboratory of Model Animal Phenotyping and Basic Research in Metabolic Diseases (2018KSYS003). The authors declare that they have no competing interests to be disclosed.

TRIAL REGISTRATION NUMBER

N/A.

The role of salivary galectin-3 and galectin-9 levels in plaque-induced gingivitis and periodontitis

Background

This study aimed to compare the salivary galectin-3 and galectin-9 levels in periodontitis, gingivitis, and periodontally healthy patients.

Methods

This study included 75 non-smokers who were systemically healthy. The clinical periodontal parameters of each participant were recorded. Individuals with periodontal health, gingivitis, and Stage II or Stage III Grade B periodontitis were allocated to the corresponding study groups (n = 25 each). Saliva samples were obtained from all individuals after they abstained from drinking and eating 1 h before sample collection. The galectin-3 and galectin-9 levels in the saliva were analyzed using enzyme-linked immunosorbent assay. One-way analysis of variance, student's t-test, Spearman correlation, and logistic regression were used for statistical analyses.

Results

The galectin-3 and galectin-9 levels were significantly higher in the periodontitis and gingivitis groups than in the healthy group (p < 0.001). The highest galectin-3 and galectin-9 levels were observed in the gingivitis group (p < 0.05). Overall, the galectin-3 levels were significantly higher than the galectin-9 levels in all the groups (p < 0.001).

Conclusions

The salivary galectin-3 and galectin-9 levels were high in patients with periodontitis and gingivitis, suggesting that they could be potential biomarkers for periodontal diseases.

Examination of the TIGIT-CD226-CD112-CD155 Immune Checkpoint Network during a Healthy Pregnancy

Background: The importance of immune checkpoint molecules is well known in tumor and transplantation immunology; however, much less information is available regarding human pregnancy. Despite the significant amount of information about the TIGIT and CD226 immune checkpoint receptors in immune therapies, very little research has been conducted to study the possible role of these surface molecules and their ligands (CD112 and CD155) during the three trimesters of pregnancy. Methods: From peripheral blood, immune cell subpopulations were studied, and the surface expression of immune checkpoint molecules was analyzed by flow cytometry. Soluble immune checkpoint molecule levels were measured by ELISA. Results: Notable changes were observed regarding the percentage of monocyte subpopulation and the expression of CD226 receptor by CD4+ T and NKT cells. Elevated granzyme B content by the intermediate and non-classical monocytes was assessed as pregnancy proceeded. Furthermore, we revealed an important relationship between the CD226 surface expression by NKT cells and the serum CD226 level in the third trimester of pregnancy. Conclusions: Our results confirm the importance of immune checkpoint molecules in immunoregulation during pregnancy. CD226 seems to be a significant regulator, especially in the case of CD4+ T and NKT cells, contributing to the maternal immune tolerance in the late phase of pregnancy.

Expression level of immune checkpoint inhibitory factors in preeclampsia

Preeclampsia (PE) is a severe complication in pregnancy, and its symptoms (proteinuria and hypertension) manifest after 20 weeks of gestation, affecting up to 8 % of pregnancies. The pregnant women's immune system uses different tolerance mechanisms to deal with a semi-allogeneic fetus. The T-cell subsets including CD8+, CD4+, and Treg play a critical role in maintaining pregnancies. The expression of immune checkpoint molecules in T-cells can ensure pregnancy at the feto-maternal interface by controlling immune responses. This research aims to evaluate the expression level of immune checkpoint factors, including PD-1, LAG-3, CTLA-4, and TIM-3 in normal pregnant women and PE patients. Decidual tissue was collected from 50 participants (25 PE and 25 control). For evaluating the genes expression, real-time PCR was employed. The western blot was used to assess the proteins level. The results of real-time PCR indicated significantly decreased expression level of these immune checkpoints in PE patients. In parallel to gene expression results, the protein level of PD-1, LAG-3, CTLA-4, and TIM-3 in the PE group was also reduced. We revealed that the profile of proteins and genes expression of immune checkpoints in the decidua of PE mothers are different from normal pregnancy and these results indicate aberrant expression of immune checkpoints such as PD-1, LAG-3, CTLA-4, and TIM-3 may cause maladaptation immune response which results in PE manifestation.