Name of the Test: Anti- Annexin V, IgG and IgM
Alias Names: Autoantibodies to Annexin V , anti-Annexin V antibodies .
Annexin V is a glycoprotein ( Mol Wt . 36 kD) that has the ability to bind to negatively charged phopholipids such as phosphotidyl serine with high affinity in a calcium- dependent manner .Based on its strong phospholipid binding activity, it inhibits in vitro the thrombinase complex and the tenase complex, resulting in potent anticoagulant activity . The occurrence of autoantibodies to annexin V has been described in several pathological disorders. It has been concluded that extracellular annexin V provides an antigenic stimulus for autoantibody production. The elevated levels of autoantibodies to annexin V (especially IgG isotype) have been demonstrated in serum samples of patients with systemic lupus erythomatosis(SLE), rheumatoid arthritis , recurrent fetal loss (miscarriage ) and pre-eclampsia . A number of studies suggest that the displacement of annexin V shield from the syncytiotrophoblast surface in the placenta by anti-annexin V antibodies is causative in the generation of a thrombogenic environment and consequently fetal loss. An increased prevalence of elevated anti-annexin V IgM, and to a lesser extent anti-annexin V IgG, was seen in recurrent spontaneous miscarriage patients.
Antibodies to Human annexin V are measured by ELISA . Microtiter plates coated with human anti-annexin V. The bound antibodies from serum samples are determined using polyclonal rabbit antihuman IgG or polyclonal rabbit anti-human IgM labeled with HRP. The results are expressed as U /ml using anti-annexin V IgG or IgM calibrators.
Specimen requirements: 0.5 ml (0.2 ml minimum) of Serum or Plasma.
Patient Preparation: Fasting samples are preferred .
Shipping Requirements: Ship the samples frozen or in ice pack.
Turnaround time: 1 week (set up every Tuesday and reported the same day).
Anti-annexin V, IgG or IgM :
Less than 10 U /ml ——- Negative
10 – 20 U /ml ————- Low positive
Greater than 20 U /ml — Positive
1.Sater MS, Finana RR ,Mustafa FE et al ( 2011) Anti-annexin V IgM and IgG autoantibodies and the risk of idiopathic recurrent spontaneous miscarriage . Reprod Immunol 89 : 78 -83.
2. Ogawa H,Zhao D, Dlott JS et al ( 2000) Elevated anti-Annexin V antibody levels in Antiphospholipid syndrome and their involvement in Antiphospholipid antibody specificities .Amer J Clin Pathol 114 : 619 – 628.
3.El-Gharib MN, Elhawary TM,Eishourbagy SH,Morad MA ( 2010 ) Anti-annexin V antibodies in women with recurrent miscarriage .Clinical Medicine Insights :Reproductive Health 4 : 29 – 33.