Anti-β2-glycoprotein I/HLA-DR antibody in infertility.

To evaluate whether anti-β2-Glycoprotein I/HLA-DR (anti-β2GPI/HLA-DR) antibody is associated with pathophysiology of infertility, 224 women with infertility were enrolled from July 2020 to December 2021 in this prospective study. The serum levels of anti-β2GPI/HLA-DR antibody (normal < 73.3 U) were determined in 224 women with infertility. Backgrounds, causes and clinical factors were compared between women with and without anti-β2GPI/HLA-DR antibody. Forty (17.9 %) of the 224 women tested positive for anti-β2GPI/HLA-DR antibody. The prevalence of endometriosis was higher in women with anti-β2GPI/HLA-DR antibody than in women without the antibody (32.5 %, 13/40 vs. 17.4 %, 32/184; P = 0.048). Logistic regression analyses revealed that, among clinical factors and diseases, endometriosis was associated with anti-β2GPI/HLA-DR antibody positivity in infertile women (adjusted-odds ratio [OR] 3.01, 95 % confidence interval [CI] 1.30-6.99; P = 0.010). Twenty-three (15.5 %) of 148 women who underwent assisted reproductive technology (ART) tested positive for anti-β2GPI/HLA-DR antibody. The prevalence of recurrent implantation failure (RIF) defined as three or more implantation failures following in vitro fertilization and embryo transfers was higher in women with ART who tested positive for the antibody (43.5 %, 10/23) than in women with ART who tested negative (20.8 %, 26/125; P = 0.032). Logistic regression analyses revealed that RIF was associated with anti-β2GPI/HLA-DR antibody positivity in women with ART (adjusted-OR 2.92, 95 % CI 1.05-8.11; P = 0.040). Anti-β2GPI/HLA-DR antibody may be associated with the pathophysiology of infertility, endometriosis and RIF; and can be a potential therapeutic target in infertility.