The impact of <italic>HLA-G, LILRB1</italic> and <italic>LILRB2</italic> gene polymorphisms on susceptibility to and severity of endometriosis.

Endometriosis is a disease in which endometriotic tissue occurs outside the uterus. Its pathogenesis is still unknown. The most widespread hypothesis claims that ectopic endometrium appears as a result of retrograde menstruation and its insufficient elimination by immunocytes. Some reports have shown expression of non-classical HLA-G molecules on ectopic endometrium. HLA-G is recognized by KIR2DL4, LILRB1 and LILRB2 receptors on natural killer (NK) and other cells. These receptors are polymorphic, which may affect their activity. In this study we investigated whether <italic>HLA-G, KIR2DL4, LILRB1</italic> and <italic>LILRB2</italic> polymorphisms may influence susceptibility to endometriosis and disease progression. We used polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism (PCR-RFLP) and allelic discrimination methods with TaqMan SNP Genotyping Assays for typing of 276 patients with endometriosis and 314 healthy fertile women. The <italic>HLA-G </italic>rs1632947:GG genotype was associated with protection against the disease and its severe stages; <italic>HLA-G</italic> rs1233334:CT protected against progression; <italic>LILRB1</italic> rs41308748:AA and <italic>LILRB2</italic> rs383369:AG predisposed to the disease and its progression. No effect of <italic>KIR2DL4</italic> polymorphism was observed. These results support the role of polymorphisms of HLA-G and its receptors LILRB1 and LILRB2 in susceptibility to endometriosis and its progression. [ABSTRACT FROM AUTHOR]