High Frequency of Anti‐Protein Z IgM and IgG Autoantibodies in Women with Idiopathic Recurrent Spontaneous Miscarriage

Citation Sater MS, Finan RR, Al‐Hammad SA, Mohammed FA, Issa AA, Almawi WY. High frequency of anti‐protein Z IgM and IgG autoantibodies in women with idiopathic recurrent spontaneous miscarriage. Am J Reprod Immunol 2011; 65: 526–531 Problem Protein Z (PZ) system is an anticoagulant pathway involved in the physiologic regulation of coagulation, and PZ deficiency reportedly enhances prothrombophilic mechanisms, including those implicated with idiopathic recurrent miscarriage (RSM). We investigate plasma anti‐PZ IgM and IgG levels in RSM women and in multiparous control women. Methods Anti‐PZ IgM and IgG levels were measured in 265 RSM women and 283 age‐matched control women by ELISA. Results Elevated anti‐PZ IgG (P < 0.001) and IgM (P < 0.001) titers were seen in patients. The areas under the curves for ROC curve for anti‐PZ IgM (0.898 ± 0.044) and IgG (0.898 ± 0.042) demonstrated no variation in diagnostic capacity. Multivariate analysis confirmed the association of elevated anti‐PZ IgM [adjusted odds ratio, aOR (95% CI) = 6.46 (2.44–17.11)] and IgG [aOR (95% CI) = 7.44 (2.54–21.79)] as independent predictors of RSM after adjusting for confounding covariates and demonstrated a clear gradation of increasing RSM risk associated with increased antibody titers. Conclusion The presence of anti‐PZ IgM and IgG antibodies are risk factors for RSM.