Antiphospholipid syndrome: a clinical and laboratorial challenge

Abstract

Antiphospholipid syndrome (APS) is an acquired autoimmune thrombophilia characterized by the presence of a heterogeneous family of antibodies that bind to plasma proteins with affinity for phospholipid surfaces. The two major protein targets of antiphospholipid antibodies are prothrombin and β 2 -glycoprotein I (β2GPI). APS leads to aprothrombotic state, and it is characterized by the occurrence of arterial, venous or microvascular thrombosis or recurrent fetal loss. The diagnosis of APS is based on a set of clinical criteria and the detection of lupus anticoagulant (LA), anticardiolipin antibodies (ACA) or anti-β 2 GPI in plasma. Although laboratory tests are essential for APS diagnosis, these tests have limitations associated with the robustness, reproducibility and standardization. The standardization of diagnostic tests for detection of APLAs has been a challenge and a variety of results have been obtained using different commercial kits and in-house techniques. An increased sensitivity of the ELISA kits for detection of ACA effectively has contributed to APS diagnosis. However, the lack of specificity associated with a high number of false-positive results is a clinical and laboratorial challenge, since such results may lead to mistaken clinical decisions, such as prescription of oral anticoagulant, leading to the risk of hemorrhaging. Furthermore, clinicians are often unfamiliar with these tests and have difficulty interpreting them, requiring interaction between clinical and laboratory professionals in order to ensure their correct interpretation.

Tuberculosis mimicking primary systemic vasculitis: not to be missed!

“…9 However, the absence of oral or genital ulcers along with a negative pathergy test rendered a diagnosis of BD unlikely. Antiphospholipid syndrome 10 may have similar presentation with gangrene, non-healing ulcers, arthritis and history of abortion. However, constitutional symptoms, necrotising lung lesions, lymphadenopathy and negative serology for anti-phospholipid antibodies ruled this out.…”

Update on antiphospholipid antibody syndrome

“…There is also a need to standardize the antiphospholipid antibody tests in the different centers, since the technique varies greatly. 26 Therefore, the APS-ACTION (Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking) was established as the first international network created to design and conduct large-scale multi-center trials in patients with persistently positive antiphospholipid antibodies. 27 Brazil actively participates in this alliance and believes that better studies will guide better practices in APS.…”

Isquemia de membro superior: um desafio diagnóstico e terapêutico - relato de caso

“…O anticoagulante lúpico deve ser pesquisado por dois métodos diferentes (tempo de veneno de víbora de Russel diluído; e tempo de tromboplastina parcial ativado), confirmando-se a sua presença na positividade de um ou dos dois métodos. Já o anticorpo anti-beta-2-glicoproteina1 é o mais específico (98%) para a doença, porém com baixa sensibilidade (9). Apesar da não realização da pesquisa do anticorpo anti-beta-2-glicoproteina1 pelo serviço hospitalar em que a paciente em estudo foi atendida, observa-se a negatividade do anticorpo anticardiolipina (IgG e IgM), que tem maior sensibilidade.…”

“…Esse resultado associado à ausência do anticoagulante lúpico torna ainda mais distante a SAF como uma hipótese diagnóstica. Ademais, a paciente não tem história de complicações obstétricas ou outros achados clínicos que possam estar relacionados à síndrome, como valvulopatia, livedo reticular, trombocitopenia, nefropatia e manifestações neurológicas (9).…”