Objective To explore the expression levels and significance of peripheral blood helper T cell-1 (Th1)/helper T cell-17 (Th17) and T cell immunoglobulin mucin molecule 3 (Tim-3 in patients with severe endometriosis (EMs).

Methods The clinical data of 120 EMs patients were retrospective analyzed, and the patients were divided into the mild group (stages I-II, n = 70) and severe group (stages III-IV, n = 50) according to the staging criteria established by the American Fertility Society (AFS). The basic data information, endometriosis fertility index (EFI) and levels of Th1/Th17 and Tim-3 were compared between two groups. The ROC curves were draw to evaluate the effectiveness of EFI score and levels of Th1/Th17 and Tim-3 in diagnosing the severe Ems. The risk factors of severity of Ems were analyzed.

Results There was no statistical significances in the age, body mass index, birth time, pregnancy time, age of menarche, menstrual cycle at the time of serum sample collection and lesion site between two groups (P ＞ 0.05). The Tim-3 score in the severe group was significantly higher than that in mild group, while the EFI score and Th1/Th17 score were significantly lower than those in mild group (P ＜ 0.01). The results of ROC analysis showed that the AUC of the EFI score, Th1/Th17 and Tim-3 in predicting the severe Ems were 0.881, 0.808, 0.867 and 0.816, respectively. The results of Multivariate logistic regression analysis showed the EFI score ＜ 5.927, Th1/Th17 ＜ 9.775 and Tim-3 ≥ 42.023 were the influencing factors of severe Ems. The results of correlation analysis showed that the peripheral blood Th1/Th17 level was negatively correlated with the severity of EMs, while the Tim-3 level was positively correlated with the severity of Ems (P ＜ 0.05).

Conclusions The EFI scores ＜ 5.927, Th1/Th17 ＜ 9.775 and Tim-3 ≥ 42.023 are the influencing factors of severe EMs. It can be used as an auxiliary index for the diagnosis of severe EMs, and provide reference for the clinical evaluation and treatment of Ems patients.