Annexin A5 and anti-annexin antibodies in patients with systemic lupus erythematosus.

Plasma levels of annexin A5 (ANX A5) and anti-annexin A5 (aANX A5) antibodies were evaluated in 51 women with systemic lupus erythematosus (SLE). The results were compared between the total SLE group, subgroups on/without immunosuppressive therapy and the control (28 women). The relationships between ANX A5/aANX A5 antibodies levels and laboratory variables (anti-cardiolipin antibodies-aCL, total cholesterol, thrombocyte count, activated partial thromboplastin time-APTT, prothrombin time, international normalized ratio-INR) were performed in the total SLE group and in the patient subgroups identified as the arithmetic mean of ANX A5 concentration in the control plus 1-4 standard deviations (SD). The whole SLE group and the subgroup on immunosuppression showed significantly higher ANX A5 and IgG aANX A5 antibodies concentrations. A weak positive correlation was found between ANX A5 and thrombocyte count, a moderate one between IgG and IgM aANX A5 antibodies, a weak negative correlation between IgG aANX A5 and APTT in the whole SLE group. SLE subgroups with ANX A5 concentrations higher than the control mean plus 3 or 4 SD showed a weak/moderate negative correlation of this parameter with aANX A5 antibodies, moderate one with IgG aCL antibodies levels, a moderate positive correlation with cholesterol concentration, moderate/high positive correlations with thrombocyte count. The association between plasma ANX A5/IgG aANX A5 levels and severity of disease was noticed. The role of aANX A5 and IgG aCL antibodies as causative factors of increased ANX A5 levels was suggested, and the relationship between ANX A5 and thrombocyte count was revealed.