Endometriosis and infertility

Polymorphisms in exons 1B and 1C of the type I interleukin-1 receptor gene in patients with endometriosis

To study possible correlation between the prevalence of polymorphisms in the type I interleukin-1 receptor gene and pelvic endometriosis. Genotypes of 223 women were analyzed: 109 women with surgically and histologically confirmed endometriosis and 114 healthy women. Distributions of two single-base polymorphisms of the human interleukin-1 receptor type I (IL-1RI) gene were evaluated: PstI, due to a C-->T transition in exon 1B and BsrBI a C-->A transition at position 52 in exon 1C. Polymorphisms were detected by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism analysis (RFLP) resolved on 3% agarose gels stained with ethidium bromide. Genotypes for PstI polymorphisms did not differ significantly among control and endometriosis (P = 0.058). However, in relation to BsrBI polymorphism, protective risk was observed for the development of endometriosis [OR 0.39-IC 95% (0.2-0.9)]. BsrBI heterozygote genotype (C/A) showed protective effect against endometriosis development.

Biases in the endometriosis literature. Illustrated by 20 years of endometriosis research in Leuven

AIM

To review the Leuven data on endometriosis to demonstrate the shifts that occurred over the years in diagnosis of endometriosis, classification of women with endometriosis and thus in interpretation of results.

RESULTS

The contributions to the LUF syndrome, to non-pigmented endometriosis, to cystic ovarian endometriosis, to deep endometriosis, to endometriosis as an immunologic disease and to the development of an animal model of endometriosis, illustrate the persistent interest in endometriosis over 20 years. Using these data it can be shown how progressively the recognition of endometriosis caused important shifts from women who in the beginning of this period were classified as normal, to women who later became classified as having minimal or mild endometriosis. This was caused initially by the active search for small typical lesions and later by the recognition of non-pigmented lesions as endometriosis. The second important shift was caused by the recognition that deep endometriosis is not only a frequent disease, but that these women are predominantly classified as having mild to moderate endometriosis and even as women without endometriosis. The third shift is still ongoing, since the deep lesions reported become progressively smaller, by the "enthusiasm" of the surgeons, and by the introduction of a menstrual clinical exam. A fourth bias in the literature concerns the diagnosis and treatment of cystic ovarian endometriosis. Together with these shifts in recognition and treatment of endometriosis, our understanding of the physiopathology of endometriosis has changed. This is illustrated by the new concepts which have emerged over this period. These are, the focal treatment of cystic ovarian endometriosis, the concept that mild endometriosis could be a normal physiological condition and the endometriotic disease theory.

CONCLUSION

To interpret the data of the literature we should be aware of the shifts that have occurred in the classification of endometriosis over the past 20 years, and which still can hamper the comparison of results between research groups.