Anti-annexin V IgG and IgM antibodies in sickle cell disease patients with vaso-occlusive crisis.

Vaso-occlusive crisis (VOC) is a significant cause of morbidity and mortality in sickle cell anemia (SCA) patients; however, its mechanisms are poorly understood. In view of their prothrombotic nature, we hypothesized that SCA-associated VOC may be due to the presence of anti-annexin V antibodies. Anti-annexin V antibodies were measured with ELISA in 177 VOC and 81 steady-state SCA patients. Anti-annexin V IgM and IgG concentrations were significantly higher in VOC patients than in steady-state patients and were associated with elevated VOC risk. After categorizing anti-annexin V antibodies, the adjusted odds ratio increased as the percentile value increased. Monovariate logistic regression analysis demonstrated a positive dose-effect relationship for anti-annexin V IgM with VOC, with increased VOC risk seen with increased antibody titers. Multivariate logistic regression analyses confirmed the association of anti-annexin V IgM, more so than IgG, as an independent VOC risk factor. Anti-annexin V IgG antibodies correlated positively with VOC type and negatively with HbF and age of VOC onset, while anti-annexin V IgM correlated positively with VOC type, duration, frequency, site, pain severity, hospitalization, and medication, and negatively with age of VOC onset and HbS levels. High levels of anti-annexin V IgM antibodies constitute a risk factor for VOC in SCA patients.

High Frequency of anti-protein Z IgM and IgG autoantibodies in women with idiopathic recurrent spontaneous miscarriage.

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.