RESUMO
Throughout pregnancy, the decidua is predominantly populated by NK lymphocytes expressing Killer immunoglobulin-like receptors (KIR) that recognize human leukocyte antigen-C (HLA-C) ligands from trophoblast cells. This study aims to investigate the association of KIR-HLA-C phenotypes in couples facing infertility, particularly recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF), in comparison to a reference population and fertile controls. This observational, non-interventional retrospective case-control study included patients consecutively referred to our Reproductive Immunology Unit from 2015 to 2019. We analyzed the frequencies of KIR and HLA-C genes. As control groups, we analyzed a reference Spanish population for KIR analysis and 29 fertile controls and their male partners for KIR and HLA-C combinations. We studied 397 consecutively referred women with infertility and their male partners. Among women with unexplained RPL (133 women) and RIF (176 women), the centromeric (cen)AA KIR genotype was significantly more prevalent compared to the reference Spanish population (p = 0.001 and 0.02, respectively). Furthermore, cenAA was associated with a 1.51-fold risk of RPL and a 1.2-fold risk of RIF. Conversely, the presence of BB KIR showed a lower risk of reproductive failure compared to non-BB KIR (OR: 0.12, p < 0.001). Women and their partners with HLA-C1C1/C1C1 were significantly less common in the RPL-Group (p < 0.001) and RIF-Group (p = 0.002) compared to the control group. Moreover, the combination of cenAA/C1C1 in women with C1C1 partners was significantly higher in the control group than in the RPL (p = 0.009) and RIF (p = 0.04) groups, associated with a 5-fold increase in successful pregnancy outcomes. In our cohort, the cenAA KIR haplotype proved to be a more accurate biomarker than the classic AA KIR haplotype for assessing the risk of RPL and RIF, and might be particularly useful to identify women at increased risk among the heterogeneous KIR AB or Bx population. The classification of centromeric KIR haplotypes outperforms classical KIR haplotypes, making it a better indicator of potential maternal-fetal KIR-HLA-C mismatch in patients.
Assuntos
Aborto Habitual , Infertilidade , Gravidez , Humanos , Masculino , Feminino , Antígenos HLA-C/genética , Estudos Retrospectivos , Motivos de Aminoácidos , Estudos de Casos e Controles , Aborto Habitual/genética , Receptores KIR/genética , Infertilidade/genética , BiomarcadoresRESUMO
Proper communication between natural killer cells and the human leukocyte antigens of the embryonic trophoblast at the maternal-fetal interface during pregnancy is essential for successful reproduction. However, specific combinations of embryonic human leukocyte antigen-C with killer immunoglobulin-like receptors on decidual natural killer cells (the immunological code of pregnancy) can be associated with obstetric morbidity and pregnancy loss. This article presents an updated review of the mechanisms underlying the interaction between embryonic human leukocyte antigen-C and maternal killer immunoglobulin-like receptors and their relevance to the physiology and pathophysiology of human reproduction.
Una adecuada comunicación entre las células asesinas naturales en la interfase materno-fetal con las moléculas de los antígenos de histocompatibilidad del trofoblasto embrionario es clave en el éxito de la reproducción. Sin embargo, combinaciones de determinados antígenos leucocitarios humanos tipo C embrionarios con los receptores tipo inmunoglobulina presentes en las células asesinas naturales deciduales (el código inmunológico del embarazo), pueden asociarse con morbilidad obstétrica y pérdidas gestacionales. En este artículo se presenta una revisión actualizada de los mecanismos subyacentes a la interacción entre el antígeno de histocompatibilidad tipo C embrionario y los receptores tipo inmunoglobulina maternos, y su relevancia tanto en la fisiología como en la fisiopatología de la reproducción humana.
