Diagnostic value of CD20 combined with CD138 positive expression in patients with chronic endometritis.

Background: This study aims to evaluate the diagnostic value of CD138 and CD20 immunohistochemical staining in chronic endometritis (CE).

Methods: A total of 131 patients with reproductive needs, treated at the Second Affiliated Hospital of Fujian Medical University between August 2020 and July 2021, were enrolled. Patients were divided into a CD138-positive group (n=91) and a CD138-negative group (n=40). All participants provided informed consent and underwent hysteroscopic examination using an Olympus 30° scope, following standard operating procedures. Lesion shape and size were recorded in detail. CE diagnosis was based on hysteroscopic findings of patchy bleeding and confirmed by endometrial biopsy of suspicious areas. Biopsy tissues were subjected to immunohistochemical staining for CD138 and CD20. Expression levels were assessed under low-power and high-power magnification (Original magnification: ×400. Scale bar: 20 μm).

Results: CD20 expression differed significantly between the CD138-positive and CD138-negative groups (χ=45.440.160, P<0.05). The kappa coefficient for agreement between CD20 and CD138 was 0.530 (95% CI 2.072-4.684, P<0.05). A significant difference in CD20 expression at ×400 magnification was also observed between the two groups (χ=12.520, P<0.05), with a kappa coefficient of 0.300(95% CI 0.594-1.164, P<0.05). The area under the ROC curve (AUC) for CD20 in predicting CE was 0.732, and 0.665 for CD20 at ×400 magnification, indicating reliable diagnostic performance for both.

Conclusions: In patients with chronic endometritis, both the positive expression of CD20 and its high-level expression at ×400 magnification provide valuable diagnostic indicators, demonstrating better diagnostic utility.