Association of Post-surgical Resection Immune Profiles with Fertility Outcomes in Patients with Endometriosis

Introduction/Purpose: Endometriosis is a benign gynecological disease which is defined as the implantation of endometrial tissue on the mesenchymal surface of peritoneal organs. This disease is associated with systemic inflammation and sub- or infertility. We have reported that endometriosis associated systemic inflammation is characterized by increased inflammatory T-helper 17 (Th17) T cells and decreased tolerant T regulatory cells (Tregs). We have also reported decreased Treg localization in the eutopic endometrium of patients with endometriosis which may favor ectopic implant immune evasion and growth, contributing to sub-fertility or infertility in these patients. Treatment for endometriosis consists of hormonal suppression with or without surgical resection of disease. How these treatments impact future fertility is still unknown, as the majority of patients with endometriosis still require treatment with assisted reproductive techniques (ARTs), such as in vitro fertilization, in order to conceive. Determination of a patient’s immune response after surgical disease resection may identify patients that are likely to conceive with ART intervention. The aim of this study was to assess if a patient’s systemic immune profile (Th17:Treg), after surgical disease resection, was associated with ART fertility outcomes in patients with endometriosis. We hypothesized that patients with greater systemic inflammation would have diminished fertility outcomes evidenced by a reduction in embryonic blastulation and implantation, as well as decreased pregnancy and live birth rates. Methods: Twenty subjects with surgically confirmed endometriosis were enrolled at Southern Illinois University School of Medicine, Department of Ob/Gyn, Division of REI and included in this nested analysis from a larger study (IRB# 14-220). Peripheral blood was collected on the day of surgery (DOS) and at ~1-3 weeks post-surgical intervention (PSI). CD4+ cells and sub-types were identified via flow cytometry using cell surface markers specific to Tregs (CD25 and FoxP3) and Th17 (ROR-gamma T). As a measure of immune status (inflammatory vs. tolerant), Th17/Treg ratio was calculated for each patient. Post-surgical ART outcomes, such as implantation, blastocyst, pregnancy and live birth rates were extracted from the electronic health records of endometriosis patients (E). Values were compared to patients with tubal factor infertility (T) (IRB# 24-482), part of the analysis involved stratification by fresh embryo transfer (FT) or frozen embryo transfer (FRT). Spearman correlation and Wilcoxon rank test were used for statistical analysis (p<0.05). Results: Included in this analysis were 15 surgically confirmed endometriosis patients who underwent a FT and 5 endometriosis subjects who underwent a FRT. Tubal factory infertility (T) patients included 66 with FT and 45 with FRT. We found that several fertility outcomes were decreased in patients with endometriosis and were dependent on embryo transfer type. Blastulation rates, which were only calculated for FT, were decreased in patients with endometriosis, E 29% vs. T 50%. However, implantation rates were comparable for both patient groups regardless of transfer type, (FT: E=40% vs. T=41% and FRT: E=67% vs. T=56%). Pregnancy rates were also decreased in patients with endometriosis, but this decrease was greater in FRT cycles (FT E=48% vs. T=52% and FRT: E=42% vs. T=64%). Similarly, live birth rates were decreased in patients with endometriosis and this was greatest in FRT cycles (FT: E=48% vs. T=52% and FRT: E=42% vs. T=64%). Immune profiles (Th17/Treg) for patients with endometriosis were not significantly altered after surgical resection (PSI) and there was no correlation of DOS Th17/Treg with any ART outcome. However, PSI Th17/Treg positively correlated with pregnancy rates (r=0.4410, p=0.02), but no other ART outcome. Conclusions: From our limited data set, we found that surgical treatment of endometriosis did not decrease systemic inflammation. We also found that patients with endometriosis have decreased ART success, which may be due to reported factors other than systemic inflammation, such as diminished oocyte quality and embryonic endometrial attachment. Our analyses did find that higher postoperative Th17/Treg ratios, indicative of inflammation shortly after surgery, may be favorable for pregnancy success, but not live birth rate. Overall, in this pilot study, surgical resection of disease may not benefit ART success because it does not effectively reduce disease associated inflammation for each patient; yet, our conclusions are limited as we did not measure immune profiles immediately prior to ART treatment. Also, we were not able to control for length of time between surgical excision of endometriosis and ART cycles. However, our findings warrant further investigations into the relationship between a patient’s immune profile, response to surgical treatment and ART success in patients with endometriosis.