title: The absence of evidence is not the evidence of absence.
authors.affiliation: Department of Clinical Immunology and IdISSC, Hospital Clínico San Carlos, Madrid, Spain Department of Microbiology I, Complutense University School of Medicine, Madrid, Spain ssramon@salud.madrid.org.
authors.forename: Silvia
authors.initials: S
authors.lastname: Sánchez-Ramón
authors.affiliation: Department of Clinical Immunology and IdISSC, Hospital Clínico San Carlos, Madrid, Spain Department of Microbiology I, Complutense University School of Medicine, Madrid, Spain.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Comins-Boo
authors.affiliation: Department of Clinical Immunology and IdISSC, Hospital Clínico San Carlos, Madrid, Spain Department of Microbiology I, Complutense University School of Medicine, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Núñez Beltrán
authors.affiliation: Unit of Assisted Reproduction, Centro Médico Millenium, Madrid, Spain.
authors.forename: Áurea
authors.initials: Á
authors.lastname: García Segovia
authors.affiliation: Department of Clinical Immunology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Juana
authors.initials: J
authors.lastname: Gil Herrera
mesh_terms: D005260:Female; D006801:Humans; D007167:Immunotherapy / Q000592:standards*; D007694:Killer Cells, Natural / Q000276:immunology*; D027724:Reproductive Techniques, Assisted / Q000592:standards*; D014599:Uterus / Q000276:immunology*