Failure to demonstrate significant antisperm antibodies in peritoneal fluid of patients with endometriosis

Antizona and antisperm antibodies in women with endometriosis and/or infertility

OBJECTIVE

To measure the levels of antigamete antibodies in serum and peritoneal fluid of women with endometriosis and/or infertility.

DESIGN

Antibody activity against human sperm and porcine oocytes was analyzed in selected subgroups of women.

SETTING

Clinic of reproduction.

PATIENT(S)

Women with endometriosis and/or infertility.

INTERVENTION(S)

No treatment was implemented before peritoneal fluid and blood sample collection.

MAIN OUTCOME MEASURE(S)

Quantitative ELISA.

RESULT(S)

Four groups of women (n = 98) were analyzed for the presence of antizona and antisperm antibodies: infertile with endometriosis (n = 30), idiopathic infertility (n = 28), fertile with endometriosis (n = 20), and healthy fertile controls (n = 20). Antibodies were analyzed simultaneously in serum and peritoneal fluid. No statistically significant differences in antibody levels were detected in serum samples among the analyzed groups. The median values for antizona and antisperm antibodies in peritoneal fluid were significantly higher in women with idiopathic infertility than in the control group. In women with unexplained infertility, a high degree of correlation (Spearman) was found between the presence of antizona antibodies in peritoneal fluid and serum (r = 0.579). A positive predictive value of 80% was calculated for the presence of antizona antibodies (>5 ng/oocyte) in the peritoneal fluid of patients with infertility.

CONCLUSION(S)

Antizona antibodies locally produced in the peritoneal fluid have diagnostic value for infertility status; however, they cannot be treated as a marker or prognostic factor for minimal endometriosis and/or its treatment.

Endometriosis: the host response

There is abundant evidence of altered immune function in endometriosis. The task that remains is to attempt a synthesis from the accumulated data, to try to make some sense of the observed phenomena and to fit them into a conceptual framework; this might permit the formulation and testing of hypotheses. Evidently, eutopic endometrium does not engender an immune response in normal subjects, otherwise the endometrium would be subject to autoimmune destruction. It has also been established that the overwhelming majority of women regurgitate menstrual debris into the peritoneal cavity. Why does this lead to endometriosis in some, but not in others? There are several possible explanations. The uterus might act as a privileged site, i.e. be exempt from immune effector mechanisms. This would certainly be conducive to the reproductive goal, the survival of the fetal allograft. Endometrium would then not enjoy the immunologic tolerance of most other tissues, and upon leaving the uterus and entering an immunocompetent environment would be subject to immune attack. In normal subjects, this could consist of elimination of menstrual debris without further sequelae. An altered response, characterized by the production of antibody that could mask receptors for cytotoxic or phagocytic effector cells, would permit persistence of ectopic endometrium. The alternative to this hypothesis is that the uterus is not a privileged site, and that the organism is normally tolerant to endometrial antigens. Menstrual debris would be eliminated intraperitoneally without loss of tolerance due to the presence of homeostatic mechanisms including suppressor T cells and suppressive cytokines. In endometriosis, this tolerance breaks down, as is the case in several autoimmune disorders, causing a chronic inflammatory response with the release of toxic factors and, eventually, peritoneal scarring. Finally, the role of cell adhesion molecules, including the integrins, is only just being explored. The behaviour of these molecules in ectopic endometrium differs from that in eutopic endometrium, and it remains to be seen whether regurgitated endometrial debris from normal subjects is different from that of endometriosis sufferers. It seems that this will be an area of intense investigation in the immediate future.