Natural autoantibodies to the gonadotropin-releasing hormone receptor in polycystic ovarian syndrome

Autoantibodies Targeting the Hypothalamic-Pituitary-Ovarian Axis in Polycystic Ovary Syndrome: Emerging Key Players in Pathogenesis?

Polycystic ovary syndrome (PCOS) is a common female endocrinopathy associated with reproductive and metabolic abnormalities. PCOS is characterized by complex pathogenesis and pathophysiology. Its multifactorial etiology and heterogeneous presentation make effective treatment difficult. Endocrine abnormalities in PCOS create a vicious cycle of overriding dysfunction involving the hypothalamic-pituitary-ovarian (HPO) axis. Most research has primarily focused on identifying genetic, epigenetic, or immunological factors underlying PCOS. In recent years, new reports have emerged on the possible involvement of antibodies directed against HPO axis components in the development of PCOS. Some of these have been shown to be able to interfere with hormone receptors or receptor binding by targeting the key domains for their function. However, the evidence is heterogeneous and challenging to interpret, given the overall predisposition to high levels of various autoantibodies found in women with PCOS. This review focuses on autoantibodies affecting the HPO axis in PCOS and their potential role in the pathogenesis of PCOS. The authors discuss PCOS as a potential antibody-mediated autoimmune disease in light of recent reports on its possible pathogenesis.

Unveiling the link: anti-protein disulfide isomerase A3 autoantibody expression and polycystic ovary syndrome risk in euthyroid autoimmune thyroiditis women

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common complication of autoimmune thyroiditis (AIT) in women, but the underlying mechanism remains unclear. Protein disulfide isomerase A3 (PDIA3) is a ubiquitous protein. We have reported that PDIA3 autoantibody (PDIA3Ab) production results from autoimmune responses against thyrocytes, resulting in its high expression in euthyroid AIT patients. This study aimed to explore potential correlations between PDIA3Ab expression and concurrent PCOS in euthyroid AIT women.

METHODS

This is a single-center cross-sectional study. All participants, who visited the First Hospital of China Medical University from April 2023 to May 2024, were assigned to four groups according to AIT and PCOS diagnostic criteria. The PDIA3Ab levels of total IgG and IgG subclasses were detected using ELISA.

RESULTS

From highest to lowest, PDIA3Ab total serum IgG levels were categorized as follows: AIT-PCOS group > AIT-non-PCOS group > non-AIT-PCOS group > non-AIT-non-PCOS group Significant differences were observed between each pair of groups, except for the non-AIT-PCOS and non-AIT-non-PCOS groups. Further analysis of the subclasses of PDIA3Ab revealed that serum IgG1 levels in the AIT-PCOS and AIT-non-PCOS groups were significantly higher than those in the non-AIT-PCOS and non-AIT-non-PCOS groups. In addition, the AIT-PCOS group had significantly higher serum IgG3 levels than the other three groups. Binary logistic regression analysis revealed that the PDIA3Ab total IgG level was an independent risk factor for concurrent PCOS in euthyroid AIT women (Q4 vs. Q1: OR, 95%CI = 5.082, 1.348-19.16). Furthermore, a trend test demonstrated a titer-dependent increase in PCOS prevalence among AIT women as the PDIA3Ab total IgG level increased.

CONCLUSIONS

The expression of serum PDIA3Ab may indicate an increased risk of PCOS in euthyroid AIT women and could potentially serve as new targets for markers or immune intervention.

Aberrant HPO Axis Alterations and Autoimmune Abnormalities in PCOS Patients with DOR: A Retrospective Analysis

BACKGROUND

There is a group of polycystic ovary syndrome (PCOS) patients in clinic who have diminished ovarian reserve (DOR) in combination. This study was designed to evaluate the differences in glucolipid metabolism, hypothalamic-pituitary-ovarian (HPO) axis-related parameters, and autoimmune antibodies in PCOS patients with and without DOR.

METHODS

A total of 2307 PCOS patients, including 1757 patients with PCOS alone and 550 patients who have both PCOS and DOR, were enrolled in this retrospective study. Parameters of glucolipid metabolism, HPO axis-related parameters, and autoimmune antibodies were measured and analyzed.

RESULTS

The prevalence of DOR among all patients with PCOS was 23.84%. Many HPO axis-related parameters, such as follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and prolactin (PRL) were significantly different in PCOS with DOR compared with PCOS without DOR. The FSH levels were positively correlated with LH, testosterone (T), and androstenedione (AD) levels, but had no association with glucolipid metabolism after adjusting for body mass index (BMI). Moreover, anti-ovarian antibody (AOAb) and anti-21-OH antibody (21-OHAb) levels were significantly elevated in PCOS patients with DOR.

CONCLUSIONS

PCOS patients with DOR showed more chaotic HPO axis hormone levels and elevated autoimmune antibodies, suggesting that autoimmune factors may be the cause of DOR in women with PCOS.

Antibodies to SARS-CoV-2 in follicular fluids and their association with assisted reproduction

Introduction

Every second woman suffering from infertility asks for medical help. There is public concern that vaccination-induced antibodies (Ab) are negatively associated with fertility. A recent study has demonstrated an association between SARS-CoV-2 vaccination and a lower pregnancy rate in the subsequent 60 days. Consequently, Ab could affect fertility success in assisted reproduction.

Methods

To address this question, we compared fertilization outcomes of vaccinated (n=35) and nonvaccinated (n=34) women. Paired serum samples and multiple follicular fluids (FF) (up to 10 from the same donor) were collected during the course of assisted reproduction and characterized for oocyte quality, the presence of Ab and trace element concentrations.

Results

The results showed a positive correlation of vaccination-induced neutralizing activity of SARS-CoV-2-Ab in serum and FF. On average, Ab concentrations in serum were higher than in the corresponding FF. However, wide variations in SARS-CoV-2 Ab titers were observed between different FF, correlating to trace element levels, even when retrieved from the same donor.

Discussion

Overall, FF contents are highly variable, but no negative association was observed between Ab in serum or FF and fertilization success and oocyte development, supporting the safety of SARS-CoV-2 vaccination during assisted reproduction.

Autoimmunity to Sphingosine-1-Phosphate-Receptors in Systemic Sclerosis and Pulmonary Arterial Hypertension

Context

Pulmonary arterial hypertension (PAH) is a frequent extracutaneous manifestation of systemic sclerosis (SSc). PAH is characterized by increased vasomotor tone, progressive remodeling of pulmonary arteries and arterioles, consequentially increased pulmonary vascular resistance, right heart hypertrophy, and eventually right ventricular failure. Autoimmunity against G-protein coupled receptors (GPCRs) has been implicated in the development of SSc-associated PAH. Sphingosine-1-phosphate (S1P) receptors (S1PR) present a potential, yet so far untested antigen for PAH autoimmunity, given the documented role of S1P/S1PR signaling in PAH pathogenesis.

Objective

We hypothesized that S1P receptors (S1PR) may constitute autoantigens in human patients, and that the prevalence of autoantibodies (aAb) to S1PR1, S1PR2 and S1PR3 is elevated in SSc patients and associated with PAH.

Methods

For this exploratory study, serum samples from 158 SSc patients, 58 of whom with PAH, along with 333 healthy control subjects were screened for S1PR-aAb. S1PR1-3 were expressed as fusion proteins with luciferase in human embryonic kidney cells and used to establish novel in-vitro assays for detecting and quantifying S1PR-aAb. The fusion proteins were incubated with serum samples, the aAb-S1PR complexes formed were precipitated by protein-A, washed and tested for luciferase activity. Commercial anti-S1PR-antibodies were used to verify specificity of the assays.

Results

All three assays showed dose-dependent signal intensities when tested with S1PR-subtype specific commercial antibodies. Natural aAb to each S1PR were detected in healthy controls with a prevalence of <10% each, i.e., 2.7% for S1PR1-aAb, 3.6% for S1PR2-aAb, and 8.3% for S1PR3. The respective prevalence was higher in the cohort of SSc patients without PAH, with 17.1% for S1PR1-aAb, 19.0% for S1PR2-aAb, and 21.5% for S1PR3. In the subgroup of SSc patients with PAH, prevalence of aAb to S1PR2 and S1PR3 was further elevated to 25.9% for S1PR2-aAb, and 27.6% for S1PR3. Notably, the majority of patients with positive S1PR2-aAb (60.7%) or S1PR3-aAb (71.9%) displayed interstitial lung disease.

Conclusion

S1PR1–3 can constitute autoantigens in humans, particularly in SSC patients with PAH. The potential pathophysiological significance for the etiology of the disease is currently unknown, but the elevated prevalence of S1PR2-aAb and S1PR3-aAb in SSC patients with PAH merits further mechanistic investigations.

Autoimmunity to the Follicle-Stimulating Hormone Receptor (FSHR) and Luteinizing Hormone Receptor (LHR) in Polycystic Ovarian Syndrome

Hyperandrogenemia and ovulatory dysfunction are hallmarks of polycystic ovary syndrome (PCOS), pointing to a deranged hypothalamus-pituitary-ovarian (HPO) axis. An autoimmune etiology of PCOS is suspected in a subset of patients due to the relatively high concordance of PCOS with common autoimmune diseases. For this reason, we tested the hypothesis that natural autoantibodies (aAb) to the follicle-stimulating hormone receptor (FSHR) or luteinizing hormone receptor (LHR) are prevalent in PCOS. To this end, new luminometric assays for quantifying aAb to the FSHR (FSHR-aAb) or LHR (LHR-aAb) were developed using full-length recombinant human receptors as fusion proteins with luciferase as reporter. Prevalence of FSHR-aAb and LHR-aAb was determined in serum samples from healthy controls and PCOS patients. Steroid hormone profiles were compared between patients with and without FSHR-aAb or LHR-aAb. Signal linearity and detection ranges were characterized and both methods passed basic performance quality checks. The analysis revealed a relatively low prevalence, with 4 out of 430 samples positive for FSHR-aAb in the control versus 11 out of 550 samples in the PCOS group, i.e., 0.9% versus 2.0%, respectively. Similarly, there were only 5 samples positive for LHR-aAb in the control versus 2 samples in the PCOS group, i.e., 1.2% versus 0.4%, respectively. Samples positive for FSHR-aAb displayed steroid hormones in the typical range of PCOS patients, whereas the two samples positive for LHR-aAb showed relatively elevated free testosterone in relation to total testosterone concentrations with unclear significance. We conclude that the FSHR and LHR constitute potential autoantigens in human subjects. However, the prevalence of specific autoantibodies to these receptors is relatively low, both in control subjects and in women with PCOS. It is therefore unlikely that autoimmunity to the LHR or FSHR constitutes a frequent cause of hyperandrogenemia or ovulatory dysfunction in PCOS.