Antiphospholipid antibodies

Purpose. – The association of antiphosphatidylethanolamine antibodies (aPE) as the only antiphospholipid antibody with antiphospholipid syndrome (APS) is discussed. The aPE was described as the sole antibody in many cases suggesting APS. aPE was not included in the Sapporo criteria for the classification of APS.Methods. – We investigated the clinical features of 20 patients with aPE only; 17 patients had symptoms potentially

Kidd blood group, though minor, carries a special importance in
transfusion medicine. Kidd antibodies are heterogeneous, as they
have a weak sociological nature and goes to undetectable levels,
so may miss routine serological tests. However, they can mount a
secondary  amnestic  reaction  leading  to  delayed  hemolytic
reaction,  especially  in  frequently  transfused  individuals. We
report a case of thalassemia child with delayed hemolytic reaction
secondary  to  Kidd  antibodies.  Conclusion:  screening  for
Alloantibodies is of prime importance, especially in frequently
transfused individuals like thalassemic children.

Essential thrombocytosis is extremely rare in children. However, when present, it is associated with increased prevalence of antiphospholipid antibodies and thrombo-hemorrhagic complications. The authors report here a child with Budd-Chiari Syndrome resulting from essential thrombocytosis and associated antiphospholipid antibodies. A 13- y-old boy presented with microcytic hypochromic anemia, hepatosplenomegaly and thrombocytosis. CT scan demonstrated calcified thrombus in inferior vena cava (IVC). Diagnosis of essential thrombocytosis was considered in view of persistent thrombocytosis, antiphospholipid antibodies, bone marrow showing increased number, clusters and giant forms of megakaryocytes and IVC thrombosis. He was started on warfarin prophylaxis and did not have thrombotic recurrence on follow up.

The target of many anti-phospholipid autoantibodies (aPL) has been shown to be a complex between anionic phospholipid and the plasma protein beta2-glycoprotein I (beta2GPI) or the protein beta2GPI alone. As aPL binding studies have been performed almost exclusively in vitrothe identity of the natural target and/or immunogen for aPL in vivo remains undetermined. The anionic phospholipids of cell membranes represent an important potential target and immunogen for aPL. Although anionic phospholipids are normally absent from the extracellular surface of cell membranes, they redistribute from the inner to the outer leaflet during apoptosis. We have previously shown that beta2GPI binds selectively to the surface of apoptotic, but not viable, cells, and that binding of beta2GPI to the surface of apoptotic cells generates an epitope recognized by aPL from patients with primary aPL syndrome and systemic lupus erythematosus. We show here that immunization of non-autoimmune mice with beta2GPI combined with, or bound to, apoptotic cells induces aPL and lupus anticoagulant activity. Generation of aPL required heterologous beta2GPI, and occurred upon immunization with apoptotic cells and beta2GPI by three different routes of administration. Importantly, for intravenous immuniz-ations, generation of aPL occurred only when apoptotic cells and beta2GPI were injected together, but not when either was injected alone, suggesting that cell-bound beta2GPI is the true immunogen for production of aPL. Unlike other models of induced aPL, adjuvant was not an absolute requirement. Induced aPL reacted with murine, as well as bovine, beta2GPI, suggesting that heterologous beta2GPI bound to apoptotic cells can break tolerance and induce auto-antibodies reactive with autologous beta2GPI. Combined with our previous data, these results show that apoptotic cells can serve as both immunogens and natural targets for aPL.

Objective: The antiphospholipid syndrome is characterized by venous and arterial thrombotic events that are often recurrent, thrombocytopenia, recurrent fetal loss, and elevated titers of antiphospholipid antibodies. A subtype of patients with a particularly overwhelming clinical picture has been termed catastrophic antiphospholipid syndrome (CAPS). In this report, we present 2 patients who exhibited a similar multisystem disorder associated with gangrenous changes in the lower extremities. Methods: Two patients with CAPS are presented, highlighting the impact of this disorder on the patients and the response to various therapeutic modalities. Results: Both patients had pulmonary, cardiac, cutaneous, and neurologic findings consistent with CAPS. In addition, they had large purulent leg ulcers associated with livedo reticularis. Amputation of the legs in each case induced remission of the systemic illness. Conclusions: We believe that infection plays a significant role in the pathogenesis and amplification of the antiphospholipid syndrome. In certain patients, this association probably is mediated via immune mechanisms, which also enhance the genesis of atherosclerosis. After the foci of infection (suppurative leg ulcers) were removed, the underlying illness improved. These case studies provide an opportunity to study the interrelationship between several confounding factors that converge and lead to the development of this autoimmune condition. Semin Arthritis Rheum 31:127-132. Copyright © 2001 by W.B. Saunders Company

The antiphospholipid syndrome (APS) is the association of thrombosis and recurrent pregnancy loss and/or pregnancy morbidity with persistent antiphospholipid antibodies (aPL). Previous studies of microparticles in patients with APS/aPL have mainly been small and findings, contradictory. To quantify endothelial and platelet microparticle levels in patients with isolated antiphospholipid antibodies or primary antiphospholipid syndrome (PAPS). We measured endothelial and platelet microparticle levels by flow cytometry in 66 aPL/PAPS patients and 18 healthy controls. Levels of circulating platelet (CD41 and CD61) and endothelial microparticles (CD51 and CD105) were significantly increased in patients with PAPS and aPL compared to healthy controls. There were correlations between platelet and endothelial microparticles levels in all patients with aPL. Platelet and endothelial microparticles are increased in all patient groups within this cohort of patients aPL. Whether they may have a ro...