Autoantibodies Cannot Be Used to Detect Endometriosis Just Yet

Levels of autoantibodies are not different in women with endometriosis.

Key Points

Highlights: 

• There seems to be no unique autoantibody profile for endometriosis and currently, none is identifiable in plasma or in peritoneal fluid. 

Importance:

• More research is needed to identify potential new biomarkers that can help diagnose endometriosis in a non-invasive manner. 

What’s done here:

• Researchers compared autoantibody expressions in the plasma and peritoneal fluid of women with endometriosis and controls. 

Key results:

• There were no significant differences in the expression of autoantibodies in the plasma or peritoneal fluid of women with endometriosis and controls.
• There were significantly higher reactivity signals for ANAPC15 and GABPB1 in the peritoneal fluid of women with stage 2 endometriosis and women with other stages of the disease.
• NEIL1, MAGEB4, and TNIP2 autoantibodies levels were significantly higher in the luteal phase than the follicular phase in peritoneal fluid samples of women with endometriosis.
• There were no differences between the luteal phase and the follicular phase in the plasma.
• There was no difference between the 2 phases of the cycle between women with endometriosis and controls.

Limitations:

• The study does not cover the entire human proteome nor detect post-translational modifications.
• The levels of autoantibody are associated with many factors including infections and the tests should be repeated for more accurate results.

Lay Summary

There seems to be no significant difference in the expression of autoantibodies in the plasma or peritoneal fluid of women with endometriosis and those without the disease. This is according to a new study published in the journal Human Reproduction.

This finding suggests that although endometriosis has been associated with several autoimmune diseases, it does not seem likely that autoimmune responses play an important role in its pathogenesis.

In order to investigate whether there are specific autoantibodies in patients with the disease, a team of researchers led by Dr. Miroslaw Wielgos from the 1st Department of Obstetrics and Gynecology, Medical University of Warsaw, in Poland, conducted a multicentre, cross-sectional study in 137 patients undergoing laparoscopy with suspicion of endometriosis. Plasma samples were obtained from all patients and peritoneal fluid samples were obtained from 98 patients. 

The authors reported that there were no significant differences in the expression of autoantibodies in the plasma or peritoneal fluid of patients and controls. 

However, there were significantly higher reactivity signals for ANAPC15 and GABPB1 in the peritoneal fluid of women with stage 2 endometriosis compared to women with other stages. Moreover, the levels of NEIL1, MAGEB4, and TNIP2 autoantibody signals were significantly higher in the luteal phase compared to the follicular phase, in peritoneal fluid samples of women with endometriosis. However, there were no differences between the two phases of the cycle in plasma. There was also no difference between women with endometriosis and those without. 

When the researchers clustered together peritoneal fluid and plasma samples, they did not find a unique autoantibody profile for endometriosis. When they compared the peritoneal fluid and plasma of the same patient, however, they found a high degree of concordance.

“Although endometriosis has been linked to different autoimmune diseases, it is unlikely that autoimmune responses mediated by specific autoantibodies play a pivotal role in the pathogenesis of this inflammatory disease,” they concluded.

Research Source: https://pubmed.ncbi.nlm.nih.gov/36749097/