Primary antiphospholipid syndrome in a hemodialysis patient with recurrent thrombosis of arteriovenous fistulas / Síndrome antifosfolípide primária em paciente em hemodiálise com trombose recorrente de fístulas arteriovenosas

ABSTRACT Introduction: The antiphospholipid syndrome is a systemic autoimmune disease defined by recurrent vascular and/or obstetrical morbidity that occurs in patients with persistent antiphospholipid antibodies. Case presentation: A patient on hemodialysis with a primary antiphospholipid syndrome presented with recurrent vascular access thrombosis, obstetrical complications, and positive lupus anticoagulant. The patient had multiple arteriovenous fistulas that failed due to thrombosis. The obstetrical morbidity was defined by one miscarriage at the 7th week of gestation and a pregnancy complicated by pre-eclampsia with preterm delivery at the 28th week of gestation. A thorough thrombophilia screening confirmed the presence of antiphospholipid antibody. Lupus anticoagulant was present in plasma, measured on two occasions 12 weeks apart. Conclusion: Thrombophilias are inherited or acquired predispositions to vascular thrombosis and have been associated with thrombosis of the arteriovenous fistula. Patients on hemodialysis with recurrent vascular access thrombosis and presence of thrombophilia should be evaluated about the need for anticoagulant therapy with a vitamin K antagonist.

RESUMO Introdução: A síndrome antifosfolipídica é uma doença autoimune sistêmica definida por morbidade vascular e/ou obstétrica, recorrente, que acomete pacientes com anticorpos antifosfolípides persistentes. Apresentação do caso: Uma paciente em hemodiálise com síndrome antifosfolípide primária apresentou trombose recorrente do acesso vascular, complicações obstétricas e anticoagulante lúpico positivo. A paciente apresentava múltiplas fístulas arteriovenosas que falharam devido à trombose. A morbidade obstétrica foi definida por um aborto espontâneo na 7ª semana de gestação e uma gravidez complicada por pré-eclâmpsia com parto prematuro na 28ª semana de gestação. Um rastreamento completo de trombofilia confirmou a presença de anticorpo antifosfolípide. O anticoagulante lúpico estava presente no plasma, medido em duas ocasiões, com 12 semanas de intervalo. Conclusão: As trombofilias são predisposições hereditárias ou adquiridas para trombose vascular e têm sido associadas à trombose da fístula arteriovenosa. Pacientes em hemodiálise com trombose recorrente de acesso vascular e presença de trombofilia devem ser avaliados quanto à necessidade de terapia anticoagulante com um antagonista da vitamina K.

Inhibidor lúpico en situaciones clínicas diferentes al síndrome antifosfolipídico / Lupus inhibitor in clinical situations other than antiphospholipid syndrome

El inhibidor lúpico (IL) es uno de los criterios de laboratorio para Síndrome Antifosfolipídico (SAF); sin embargo, puede detectarse en individuos asintomáticos o estar asociado a otras situaciones clínicas. Presentamos un análisis retrospectivo de 1000 exámenes consecutivos para IL (TTPA, DRVVT) de los cuales 249 casos no presentaban criterios clínicos de SAF. Aplicando los criterios SSC-ISTH, hallamos IL+ en 27,30% (205/751) y 43,37% (108/249) de los casos con y sin criterios clínicos de SAF respectivamente; analizándose en estos últimos casos las características clínicas y de laboratorio. Contexto clínico de casos IL+ sin SAF: 18,52% asintomáticos, 34,26% síntomas de sangrado y 47,22% otras manifestaciones. Otras alteraciones de laboratorio en casos IL+ sin SAF, con síntomas de sangrado: detectamos alteraciones plaquetarias, descenso de VWF:RCo y/o VWF:Ag, disminución de FVIII, FV, FVII, FXI o fibrinógeno e hiperfibrinolisis en el 54,05% de los casos. El análisis mostró detección de IL+ en un número importante de estudios (108/1000) sin criterios SAF. Los casos con IL+ y sangrado representan un desafío particular, al requerir evaluar otros posibles defectos subyacentes, que pudiesen justificar el comportamiento clínico. La detección e identificación de defectos combinados requiriere de un análisis minucioso, a fin de alcanzar un diagnóstico correcto, esencial para tomar decisiones terapéuticas adecuadas. (AU)

Despite lupus anticoagulant (LA) is one of the laboratory criteria for antiphospholipid syndrome (APS), it can be present in asymptomatic subjects or it can be associated with other clinical settings. We present a retrospective analysis of 1000 consecutive LA assays (APTT, DRVVT), 249 of them were performed in patients without clinical criteria for APS. According to ISTH criteria, positive LA was found in 27.30% (205/751) and 43.37% (108/249) of cases with or without APS criteria respectively; in the last group, the analysis of clinical background and laboratory characteristics was done. Clinical background of LA+ cases without APS: 18.52% asymptomatic, 34.26% bleeding symptoms and 47.22% other clinical settings. Other abnormal laboratory tests in LA+ cases without APS and bleeding symptoms: platelet dysfunction; low VWF:RCo and/or VWF:Ag; decrease of FVIII, FV, FVII, FXI or fibrinogen and hyperfibrinolysis were found in the 54.05% of the cases. The analysis showed positive LA in an important number of cases (108/1000) without criteria of APS. Those LA+ cases with bleeding symptoms represent a particular challenge because other possible underlying defects have to be analysed in order to explain the clinical behaviour. The detection and identifications of combined defects required a careful analysis in order to achieve accurate diagnosis, essential for therapeutic decisions. (AU)

Antiphospholipid syndrome: a clinical and laboratorial challenge / Síndrome do anticorpo antifosfolípide: um desafio clínico e laboratorial

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 β2-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-β2GPI 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.

A síndrome do anticorpo antifosfolípide (SAAF) é uma trombofilia autoimune adquirida, caracterizada pela presença de uma família heterogênea de anticorpos que se ligam a proteínas plasmáticas com afinidade, por superfícies fosfolipídicas. As duas principais proteínas-alvo dos anticorpos antifosfolípides (AAF) são a protrombina e a β2-glicoproteína 1 (β2GP1). A SAAF está associada a um estado protrombótico e é clinicamente caracterizada pela ocorrência de trombose arterial, venosa ou microvascular ou perda fetal recorrente. O diagnóstico da SAAF é baseado em um conjunto de critérios clínicos e na detecção plasmática de anticoagulante lúpico (AL), anticorpo anticardiolipina (ACA) ou antiβ2GP1. Embora os testes laboratoriais sejam de fundamental importância para o diagnóstico da SAAF, eles apresentam limitações associadas à robustez, à reprodutibilidade e à padronização. A padronização de testes diagnósticos para a pesquisa de AAF tem sido um desafio, pois uma variedade de resultados pode ser obtida utilizando diferentes kits comerciais e técnicas in-house. Um aumento da sensibilidade dos kits de ELISA para a detecção do ACA contribuiu efetivamente para o diagnóstico da SAAF. No entanto, a falta de especificidade, associada a um número elevado de resultados falso-positivos, é um desafio clínico e laboratorial, uma vez que tais resultados podem levar a decisões clínicas erradas, como a prescrição de anticoagulante oral, levando ao risco de hemorragia. Além disso, os clínicos muitas vezes não estão familiarizados com esses testes e têm dificuldade em interpretá-los, sendo necessária a interação da clínica e dos profissionais do laboratório para assegurar sua correta interpretação.

Anticardiolipin antibodies and lupus anticoagulants among women undergoing in vitro fertilization in Jamaica / Anticuerpos anticardiolipinas y anticoagulantes lúpicos entre mujeres a las que se les realiza FIV en Jamaica

OBJECTIVE: The aims of this study were to evaluate the effect of anticardiolipin antibody (aCL) and lupus anticoagulant (LA) on the outcome of the in vitro ferlitization (IVF) cycles and to determine the prevalence of these antibodies in infertile women seeking IVF in Jamaica. METHODS: A retrospective cohort study was performed to determine if screening patients for aCL and LA had any significant impact on the outcome of the IVF process. Each patient's hospital record, between March 2000 and March 2010, was collected and the relevant data extracted. RESULTS: The prevalence of aCL in this cohort of Jamaican women was moderate/high positive 3.88%, low positive 0.68% and those with negative aCL results 95.4%. The prevalence of women who were LA positive was 4.1% and 0.9% of the women were positive for both LA and aCL. Of the patients who were LA and/or aCL positive, eight out of 30 patients (26.7%) had a positive pregnancy test in comparison to 61 out of 181 patients (33.7%) who were LA and/or aCL negative (p = 0.5787). CONCLUSION: The prevalence of positive aCL and/or lA in infertile women seeking IVF in Jamaica is 7.76%. The presence of these antibodies did not affect the pregnancy rate of these women nor did it demonstrate an increased risk for IVF cycle cancellation or ovarian hyperstimulation syndrome. Screening women undergoing IVF for these antibodies is not justified.

OBJETIVO: Los objetivos de este estudio fueron evaluar el efecto del anticuerpo anticardiolipina (aCL) y el anticoagulante lúpico (LA) sobre el resultado de los ciclos de la fertilización en vitro (FIV), así como determinar la prevalencia de estos anticuerpos en mujeres estériles que buscan tratamiento de FIV en Jamaica. MÉTODOS: Se realizó un estudio de cohorte para determinar si el tamizaje de pacientes para detectar el anticuerpo anticardiolipina y el anticoagulante lúpico tenía un impacto significativo en el resultado del proceso de FIV. Se obtuvieron las historias clínicas hospitalarias de cada una de las pacientes, entre marzo de 2000 y marzo de 2010, y se extrajeron los datos pertinentes. RESULTADOS: La prevalencia de aCL en esta cohorte de mujeres jamaicanas fue 3.88% moderada/alta positiva, 0.68% positiva baja, y aquellas con resultados negativos de aCL, 95.4%. La prevalencia de mujeres con resultados de anticoagulante lúpico positivos fue 4.1%, y 0.9% de las mujeres resultaron positivas con respecto tanto al LA como al aCL. De las pacientes que fueron positivas al LA y/o al aCL, ocho de cada 30 pacientes (26.7%) tuvieron una prueba de embarazo positiva, en comparación con 61 de cada 181 pacientes (33.7%) negativas al LA y/o al aCL (p = 0.5787). CONCLUSIÓN: La prevalencia de resultados positivos en relación con anticuerpos anticardiolipinas y/o anticoagulantes lúpicos en mujeres estériles que buscan FIV en Jamaica es 7.76%. La presencia de estos anticuerpos no afectó la tasa de embarazo de estas mujeres, ni mostró un aumento de riesgo de la cancelación del ciclo FIV, o riesgo de síndrome de hiperestimulación ovárica. El tamizaje en busca de estos anticuerpos en mujeres que buscan tratamiento de FIV, no está justificado.

Efecto de los anticuerpos antifosfolipídicos en la formación y degradación de la malla de fibrina en pacientes con aborto recurrente / Effect of antiphospholipid antibodies on the formation and lysis of fibrin network in patients with recurrent miscarriage

En el presente trabajo se estudió el proceso de formación y disolución de la malla de fibrina y la generación de plasmina en un grupo de pacientes con aborto recurrente (AR) debido a la presencia de anticuerpos antifosfolipídicos (N= 10), mujeres con AR sin el síndrome antifosfolipídico (SAF) (N= 6) y se comparó con un grupo de mujeres sanas (N= 8). Del grupo de pacientes estudiadas con SAF, nueve fueron positivas para anticuerpos anticardiolipina (aCL), cinco para la anti-b2-glicoproteína I (anti-b2GPI), cuatro para ambos anticuerpos, una para anticuerpos antiprotrombina (aPT) y anticoagulante lúpico (AL). El proceso de formación de la fibrina y su disolución fue estudiado por turbidimetría y la generación de plasmina mediante sustrato cromogénico S2251. Las curvas de polimerización de la(s) paciente(s) con AR sin SAF y AL presentaron un incremento en la pendiente y turbidez final, comparado con las del grupo control de mujeres sanas. La velocidad de disolución del coágulo fue mayor en la paciente con AL (21 ± 0) 10-4 DDO/seg y en las AR sin SAF (19,6 ± 5,7) 10-4 DDO/seg, comparado con el grupo control (14,5 ± 2,8) 10-4 DDO/seg. La generación de plasmina estuvo incrementada solamente en las AR sin SAF (85 ± 24%) comparado con 52 ± 3% en el grupo control, p= 0,005. Los cambios observados en el proceso de polimerización y fibrinólisis de la(s) paciente(s) con AR sin SAF y AL pudieran estar relacionados con el incremento en los niveles de fibrinógeno, mientras que los de la generación de plasmina con la entidad mórbida.

The present work was intended to study the process of fibrin formation and lysis and plasmin generation in a group of patients with recurrent miscarriage (RM), due to the presence of antiphospholipid antibodies (N= 10); as well as in women with RM without the antiphospholipid syndrome (APS) (N= 6), compared with those of a group of healthy women (N= 8). In the group of patients with APS, nine were positive for antibodies against cardiolipin (aCL), five for anti-b2-glycoprotein I (anti-b2GPI), four for both antibodies, and one for antibodies against prothrombin (aPT) and lupus anticoagulant (LA). Fibrin formation and lysis was followed by turbidity and plasmin generation using chromogenic substrate S2251. The polymerization curves from RM patients without APS and the LA patient showed an increased slope and maximum turbidity compared to those of the control group. The speed of lysis was higher in the LA patient (21 ± 0) 10-4 DOD/seg and the RM patients without APS (19.6 ± 5.7) 10-4 DDO/seg, compared to that of the control group (14.5 ± 2.8) 10-4 DDO/seg. Plasmin generation increased only in RM patients without APS (85 ± 24%) against the control group (52 ± 3%), p= 0.005. The changes observed in the fibrin polymerization and lysis process of women with RM without APS and LA seem to be related to their higher fibrinogen levels, while the increased plasmin generation was related to the patients´ morbidity.

Clinical Implications of Elevated Antiphospholipid Antibodies in Adult Patients with Primary Immune Thrombocytopenia

BACKGROUND/AIMS: Antiphospholipid antibodies (aPL) have been detected in various proportions of patients with primary immune thrombocytopenia (ITP), but the clinical significance of this is debatable. The present study aimed to determine the frequency and clinical implications of elevated aPL in adult patients with ITP. METHODS: We prospectively studied newly diagnosed adult patients with ITP who were enrolled between January 2003 and December 2008 at Chungnam National University Hospital. They were evaluated for the presence of lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) at diagnosis and were followed for the development of thrombosis. RESULTS: Seventy consecutive patients with ITP (median age, 48 years; range, 18 to 79) were enrolled. Twenty patients (28.5%) were positive for aPL at the time of diagnosis: aCL alone in 15 (75%), aCL and LA in two (10%), and LA alone in three (15%). Patients who had platelet counts < 50,000/microL were administered oral prednisolone with or without intravenous immune globulin. No difference was found between the aPL-positive and -negative groups regarding gender, initial platelet count, and response to the therapy. After a median follow-up of 20 months (range, 2 to 68), two of 20 patients who were aPL-positive (10%) developed thrombosis, whereas no thrombotic event was found among those who were aPL-negative. CONCLUSIONS: Our data suggest that aPL levels should be determined at the initial presentation of ITP and that patients found to be aPL-positive should receive closer follow-up for thrombotic events.

Prevalence and Clinical Associations of Lupus Anticoagulant, Anticardiolipin Antibodies, and Anti-beta2-glycoprotein I Antibodies in Patients with Systemic Lupus Erythematosus / 대한진단검사의학회지

BACKGROUND: The presence of antiphospholipid antibodies (aPLs) is associated with the clinical features of antiphospholipid syndrome (APS), which comprises venous and arterial thrombosis and pregnancy loss, and systemic lupus erythematosus (SLE). The prevalence of aPLs has been reported to be different in patient populations affected by either of these conditions. We performed a retrospective study to evaluate the prevalence and clinical associations of aPLs, including lupus anticoagulant (LAC), anticardiolipin (aCL), and anti-beta2-glycoprotein I antibodies (anti-beta2-GPI) in a cohort of Korean patients with SLE. METHODS: This study included samples from 88 SLE patients for whom aPL testing had been advised between June 2006 and July 2009 at the Dong-A University Hospital. Serum and plasma samples were tested for LAC, aCL (IgG, IgM), and anti-beta2-GPI (IgG, IgM) antibodies. Clinical data from patients were obtained from a review of medical records. RESULTS: LAC was the most common (34.1% of total patients, 30/88) antibody, followed by IgM aCL (31.8%, 28/88), IgG aCL (18.2%, 16/88), and IgM and IgG anti-beta2-GPI (both 5.7%, 5/88 each). Positivity for LAC was strongly associated with venous/arterial thrombosis (P=0.002). CONCLUSIONS: LAC was the most common antibody detected in Korean SLE patients and is shown to have a significant association with the presence of venous/arterial thrombosis. The measurement of LAC may be clinically useful in identifying patients with SLE who are at a high risk for venous/arterial thrombosis.

Prevalence of Antiphospholipid antibodies in Syrian patients with thrombosis

Antiphospholipid antibodies [aPL] are a heterogeneous family of antibodies associated with thrombosis and other complications. To study the prevalence of aPL in patients with thrombosis at Aleppo University Hospitals, Syria. One hundred and fifty-seven patients with venous and arterial thrombosis and 63 healthy controls were studied. Anticardiolipin antibodies [aCL] and Lupus anticoagulant [LA] were determined. Thirty-four out of 157 [21.7%] patients with thrombosis had some type of aPL. aPL was also found in four healthy subjects [4/63=6.3%]. Eighteen patients [11.5%] were positive for LA, 20 [12.7%] for aCL antibodies and 4 [2.6%] were positive for more than one aPL. Patients without risk factors for thrombosis and having positive aPL were 23/34 [67.7%]. Fourteen out of 78 [17.9%] patients with arterial thrombosis, and 20/79 [25.3%] with venous thrombosis were positive for at least one aPL. Our study showed a significant prevalence of aPL in patients with thrombosis. It seems that aPL is a risk factor for venous and arterial thrombosis, especially in patients with no conventional risk factors

Usefulness of Silica Clotting Time for Detection of Lupus Anticoagulants / 대한진단검사의학회지

BACKGROUND: The presence of lupus anticoagulants (LA) is a strong risk factor for thrombosis in antiphospholipid syndrome. We investigated the usefulness of addition of silica clotting time (SCT) to the pre-existing dilute Russell's viper venom test (dRVVT) for detection of LA. Also, we analyzed differences in the thrombotic features and the characteristics of antiphospholipid antibodies between dRVVT and SCT. METHODS: A total of 167 patients positive for LA or anti-cardiolipin (anti-CL) antibody and 76 healthy controls were enrolled. The dRVVT and SCT were used for detection of LA. Anti-CL, anti-beta2-glycoprotein I (anti-beta2 GPI) and anti-prothrombin (anti-PT) antibodies were measured using commercial ELISA kits. RESULTS: In detection of thrombosis, the sensitivity of the combined test of SCT and dRVVT was 56.4%, which was higher than that of dRVVT alone (46.2%) or SCT alone (23.1%). The specificity of the combined test (80.9%) was comparable to that of dRVVT (81.9%). Also, odds ratio for predicting thrombosis was higher in the combined test than in dRVVT or SCT alone. When normalized LA ratio of the two tests was compared, the group of patients with higher ratio of SCT showed significantly higher prevalence of recurrent abortion and higher positivity of IgG types of anti-CL, anti-beta2 GPI and anti-PT than the group with higher ratio of dRVVT. CONCLUSIONS: Addition of SCT to dRVVT can improve the detection sensitivity of thrombosis in LA test. And the high normalized LA ratio of SCT may be a useful parameter for detection of recurrent abortion.

Antiphospholipid antibodies in young myocardial infarction patients.

Myocardial infarction (MI) is a multi-factorial disease which claims many young lives. There are very few Indian studies that have investigated antiphospholipid antibodies (APLs) in MI patients. APLs have been implicated in arterial thrombosis including premature coronary artery and cerebrovascular thrombosis. In the present study, the prevalence of two clinically significant APLs--anticardiolipin antibody (ACA) and lupus anticoagulants (LA) in young MI patients was studied and compared with age- and sex-matched controls. Fifty healthy blood donors and 40 young MI patients (less than 45 yrs) diagnosed according to the American Heart Association guidelines were recruited for the study. The criteria for diagnosis were presence of atleast two of three classical findings including: clinical symptoms, diagnostic ECG, and presence of one or more cardiac biomarkers out of raised CK-MB isoform and T-troponin on serial measurement. LA and ACA were tested by lupus-sensitive activated partial thromboplastin time (aPTT) and ELISA respectively. Elevation of ACA was observed in 9 patients, while 6 were positive for LA. ACA of IgG isotype was detected in 8 patients. One patient had LA and raised ACA of IgG and IgM isotypes. Antiphospholipid antibodies were found to be significantly associated with MI in young patients, when considered together (p < 0.05) and in coronary thrombosis, mild elevation of ACA may be considered significant.

Avances sobre síndrome antifosfolípido / Advances in antiphospholipid syndrome

El Síndrome antifosfolípido (SAF) es una trombofilia adquirida, que se caracteriza por presentar eventos trombóticos recurrentes y complicaciones obstétricas en presencia de anticuerpos antifosfolípidos (aFL), los cuales son pesquisados por pruebas de laboratorio como anticoagulante lúpico y anticuerpos anticardiolipina. En esta revisión se muestran los aspectos más relevantes del SAF, destacando los avances en fisiopatología y criterios diagnósticos.

Presence of Lupus anticoagulant in an asymptomatic Nigerian

Background:The lupus anticoagulant (LA) is one of the antiphospholipid antibodies (aPL); which prolong phospholipid- dependent coagulation tests by interfering with coagulation reactions that depend on protein - phospholipid complexes in vitro. Method: A 25 year old 'healthy' male Nigerian was screened for the presence of any coagulation abnormality using the KCT; PT and platelet count; after volunteering for his plasma to be used in the preparation of normal pooled plasma in a study. Results: He was disco- vered to have a prolonged KCT; PT and normal platelet count. Based on the prolonged KCT his plasma was subjected to mixing studies with various concentration of normal pooled plasma; the KCT index was calculated and a curve was plotted. His KCT index was 1.6 and the curve convex in the left axis suggesting the presence of LA. His past medical history and physical examination were not remarkable.Three months after the initial study; a repeat KCT index was 1.4 and the subject asymptomatic. Conclusion: From literature review this is the first report of LA in an asymptomatic adult Nigerian; the importance of this finding is discussed

Activated protein C resistance and lupus anticoagulant activity induced by plasma and purified monospecific human IgG anti-β2-glycoprotein-I antibodies / Resistencia a la proteína C activada y actividad de anticoagulante lúpico inducidas por plasma y por anticuerpos purificados humanos del IgG anti β2-glicoproteína I

ABSTRACT Introduction. We investigated the activated protein C resistance (APCR) phenotype and the lupus anticoagulant (LA), activity induced by anti-β2-glycoprotein-I (anti-β2GP-I) antibodies. Patients and methods. We studied plasma and sera samples from 29 patients with persistently positive anti-β2GP-I: 22 with thrombosis (12 with primary APS, 10 with APS secondary to SLE) and seven without thrombosis (all with SLE); 25 healthy subjects were studied as controls. We detected anticardiolipin antibodies (ACA); IgG (and its subclasses) and IgM anti-β2GP-I, on irradiated and non-irradiated plates by ELISA. APCR was assessed by the activated partial thromboplastin time (APTT)-based assay and by the modified test. The FV Leiden mutation was studied by PCR. LA determination included screening and confirmatory dRVVT. Serum anti-β2GP-I were affinity purified on sepharose columns and their isotype, subclass, and reactivity against various antigens were studied by ELISA. Results. We found that titers of IgG anti-β2GP-I on irradiated plates were higher than on non-irradiated plates (p = 0.002), IgG2 was the predominant subclass. Fifteen patients (13 with thrombosis) had LA and 15 (also 13 with thrombosis) induced the APCR phenotype. Eleven (all with thrombosis) had both. Two patients were heterozygous for the Leiden mutation. Two purified antibodies, monospecific for β2GP-I, induced an in vitro APCR phenotype and LA activity. Conclusions. Our results seem to indicate that the inhibition of the APC anticoagulant function by IgG2 anti-β2GP-I with LA activity may be one of the responsible mechanisms of thrombophilia in patients with APS.

Introducción. Investigamos la resistencia a la proteína C activada (RPCA) y la actividad de anticoagulante lápico (AL), inducidas por anticuerpos anti-β2-glicoproteína-I (anti-β2GP-I). Pacientes y métodos. Estudiamos los plasmas y sueros persistentemente positivos para anti-β2GP-I de 29 pacientes: 22 tuvieron trombosis (12 con síndrome de antifosfolípidos (SAF) primario y 10 con SAF secundario a lupus erítematoso generalizado (LEG)) y siete sin trombosis (todos con LEG). Como controles estudiamos 25 sueros de personas clínicamente sanas. Detectamos anticuerpos anticardiolipina, anti-β2GP-I IgG (y sus subclases) e IgM por ELISA en placas irradiadas y no irradiadas. Evaluamos la RPCA por medio del tiempo parcial de tromboplastina activada y por la prueba modificada. Estudiamos la mutación FV de Leiden por PCR y el anticoagulante lápico con el método de dRVVT screening y confirmatorio. Después de purificar los anti-β2GP-I séricos con una columna de antígeno unido a sefarosa, analizamos por ELISA sus isotipos, subclases y reactividad contra β2GP-I y algunos fosfolípidos. Resultados. Los títulos de anti-β2GP-I IgG fueron más altos en placas irradiadas que en no irradiadas (p = 0.002), predominó la subclase IgG2. Quince plasmas (13 de pacientes con trombosis) tuvieron AL y 15 (13 también de pacientes con trombosis) indujeron el fenotipo de RPCA. Once plasmas (todos de pacientes con trombosis) indujeron ambas actividades. Dos pacientes fueron heterocigotos para la mutación de Leiden. Dos anticuerpos purificados monoespecíficos para β2GP-I indujeron el fenotipo de la RPCA y la actividad de AL in vitro. Conclusiones. Nuestros resultados sugieren que la RPCA, inducida por los anti-β2GP-I que concomitantemente tienen actividad de AL, puede tener implicaciones patogénicas en la trombofílía del SAF.

Avaliação do desempenho dos reagentes do tempo de tromboplastina parcial ativada utilizados para detectar o anticoagulante lúpico / Assessment of the performance of reagents of activated partial thromboplastin time used to detect the lupus anticoagulant

INTRODUÇAO: O anticoagulante lúpico é uma imunoglobulina pertencente à família dos anticorpos antifosfolípides. A sua ação in vitro é interferir nos testes de coagulação dependentes de fosfolípides. O tempo de tromboplastina parcial ativada (TTPA) é um teste utilizado como screening na pesquisa do anticoagulante lúpico. Os reagentes utilizados neste teste apresentam grandes variações quanto à sensibilidade. OBJETIVO: Avaliar o desempenho dos reagentes do TTPA e detectar a presença do anticoagulante lúpico através de diferentes testes da coagulação. MATERIAL E MÉTODO: A pesquisa do anticoagulante lúpico foi realizada em 50 amostras plasmáticas de pacientes do sexo feminino através dos testes do TTPA, do tempo de coagulação do caulim (TCC), do tempo de tromboplastina parcial ativada diluída (TTPAd) e do tempo do veneno da víbora de Russel diluído (TVVRd). Três cefalinas comerciais foram avaliadas pelos testes do TTPA e do TTPAd. Na comparação entre os reagentes estudados foi aplicado o cálculo do intervalo de confiança (95 por cento). RESULTADOS: Os três reagentes avaliados apresentaram boa concordância e os métodos utilizados responderam bem à pesquisa do anticoagulante lúpico. DISCUSSAO E CONCLUSAO: As três cefalinas comerciais avaliadas podem ser utilizadas na rotina laboratorial para a pesquisa do anticoagulante lúpico.

Lupus anticoagulant in immune thrombocytopenic purpura.

OBJECTIVE: Antibodies against phospholipid antigens (APA) have been demonstrated in adult idiopathic(immune) thrombocytopenic purpura (ITP), but their clinical and pathogenetic significance has remained elusive. Also there are no such studies available in pediatric ITP cases. In this study, the prevalence and clinical significance of APAs were investigated in pediatric patients with ITP. METHODS: Forty newly diagnosed ITP patients (age 2-13 years) were prospectively studied. They were evaluated for the presence of lupus anticoagulant (LA). RESULTS: Eleven patients (27.5%) were LA positive at the time of diagnosis. No statistically significant differences were found between the LA-positive and LA-negative groups regarding gender, initial platelet counts, or response to methyl prednisolone therapy. After 6 months of follow up, 5 of the 11 LA-positive cases were still positive for LA. The frequency of LA positivity found in this pediatric age group was similar to that reported in adult patients. CONCLUSION: In view of the fact that in adult patients with ITP, the persistent presence of APAs is an important risk factor for the development of antiphospholipid syndrome, the same may also hold true for pediatric ITP patients, and thus 'demands long term follow up for these patients.

Aplicación del tiempo de tromboplastina parcial activado (TTPA) con tiempo de incubación modificado en el diagnóstico del anticoagulante lúpico (AL) / Clinical application of the activated partial thromboplastin time (APTT) with modified incubation time for the diagnosis of lupus anticoagulant (LA)

Background: Although several tests are used to screen for the presence of LA, none detects all its types. The shortening of APTT observed when the pre-incubation period is prolonged, proved to be a sensitive test for the presence of LA. Material and methods: We determined the APTT, performed with a 4 or 15 min preincubation period (APTTs and APTT15 respectively), in 22 healthy subjects, 3 commercial positive controls for LA, 16 patients with a previous diagnosis of LA and 54 patients with recurrent fetal loss and/or infertility. Evidence of LA was established by a positive Staclot-LA test. Results: APTTs and APTT15 were 31.5±4.7 and 28.4±4.5 seconds respectively in samples from 22 normal subjects. The figures in samples with LA, were 71.5±20.3 s and 58.6±18 s respectively. The difference between the two APTTs performed on an individual sample was defined as the APTT 4-15 and was 2.6±2.0 in normal subjects 2.5±2.8 in 13 patients anticoagulated with warfarin, -10.0±6.5 in 13 patients receiving heparin, and 13.2±4.9 in 15 patients with LA. The test values for LA patients were significantly higher than those for normal subjects (p <0.0001). For values over 5, the APTT 4-15 had 93.3 per cent sensitivity and 100 per cent specificity. In one patient with recurrent fetal loss or infertility, who was LA positive, the APTT 4-15 was positive with a value of 14. Conclusions: This modified TTPA is easy to perform, and provides a reasonably discriminatory value for the presence of LA. Therefore, we recommend the TTPA 4-15 to screen for LA.

Antiphospholipid antibodies--our experience.

Antiphospholipid antibodies (APA) have aroused multispeciality interests. In our study of 200 cases worked up for APA, we have used a few simple coagulation tests to detect lupus anticoagulant (LA) and ELISA to detect anticardiolipin antibodies. The positivity rate for LA among cases with recurrent pregnancy loss was 4.16% and for aCL 20.8%. The positivity rate for LA in patients with venous thrombosis was 6.2%, in arterial thrombosis was 7.14% and in SLE patients was 58.3%. In conclusion APAs are to be looked for in cases of recurrent pregnancy loss, thrombosis in people < 45 years of age without risk factors and SLE patients to assess the thrombotic risk and to decide on anti coagulant therapy for further management.

Síndrome antifosfolípido catastrófico y falla cardíaca aguda. Caso clínico / Catastrophic antiphospholipid syndrome and acute heart failure. Report of a case

A 33 years old woman was admitted to the hospital after four days with cough, dyspnea, orthopnea and hemoptysis. Blood pressure was 170/90 mmHg, pulse was 112 and temperature was normal. She had cyanosis and a left ventricular gallop, without heart murmurs. A chest radiograph revealed pulmonary edema and echocardiogram showed a global left ventricular systolic disfunction. Oxygen and furosemide were started, but cardiopulmonary collapse ensued. The patient was supported with mechanical ventilation and treated with inotropic drugs. A right sided cardiac catheterization showed pulmonary wedge pressure of 18 mmHg and a cardiac index of 3 l/min/m2. The levels of creatinine and urea nitrogen were elevated and a urine protein was 97 mg/dl. Coagulation tests were normal except by a positive lupic anticoagulant. Markers of connective tissue diseases or vasculitis were negatives. The clinical evolution suggested that a catastrophic antiphospholipid syndrome was ongoing. Intravenous corticoids, gammaglobulin and cyclophosphamide were administered with transient improvement. On her fourth day of treatment, the patient presented sudden pulmonary bleeding and embolism. A plasmapheresis was performed with improvement of renal, cardiac and pulmonary function. After this episode, the patient has been treated with prednisone and oral anticoagulants treatment for the last two years, without further clinical events.

Laboratory identification of lupus anticoagulants using the combination of activated partial thromboplastin time and Russell's viper venom at two phospholipid concentrations.

The most appropriate combination of tests for lupus anticoagulants (LA) is unknown. The standard double centrifugation method to prepare plasma was inadequate for platelet elimination, interfering with kaolin clotting time and mixing studies. In the present study, the percentage correction of activated partial thromboplastin time (APTT) and Russell's viper venom time (RVVT) by high compared with low concentrations of phospholipid was used for both screening and confirmation of LA. Abnormality in either one was reported as positive. The specificity of the tests in 122 individuals without LA was 100 per cent for RVVT and 96.7 per cent for APTT, which yielded false positive by heparin. The mixing study was omitted from the authors' strategy without decreasing the specificity. In 795 patients with thrombosis, LA was detectable in 6.03 per cent. The sensitivity of diluted activated partial thromboplastin time (dAPTT) and diluted Russell's viper venom time (dRVVT) alone, compared with the combination of the two was 83.3 per cent and 79.2 per cent respectively. Therefore, this new test scheme is a simple, inexpensive and efficient method for Thai patients.

Síndrome antifosfolípido primario y secundario: estudio comparativo de anticuerpos diagnósticos / Primary and secondary antiphospholipid syndrome: comparative study of diagnostic antibodies

Se conoce como Síndrome Antifosfolípido a la asociación de trombosis venosas y/o arteriales, pérdidas fetales recurrentes y/o trombocitopenia junto con la presencia de anticuerpos antifosfolípidos. Este puede ser primario si no presenta patologías asociadas o secundario en el caso de asociarse a otras enfermedades autoinmunes. Los objetivos de este trabajo fueron: comparar la prevalencia de anticuerpos antifosfolípidos: VDRL, anticoagulante lúpico, Acs anti-cardiolipina (IgG) y Acs anti-ß2Glicoproteína I (Acs anti-ß2GPI) en pacientes con síndrome antifosfolípido primario y secundario (SAF 1º-SAF 2º); evaluar la relevancia diagnóstica de cada anticuerpo y en pacientes con SAF 2º y lupus eritematoso sistémico (LES), correlacionar los Acs anticardiolipina con la presencia de Acs anti-DNAdc. Se estudiaron 100 pacientes: SAF 1º (n=40), SAF 2º (n=60) y 79 controles normales. La VDRL se determinó por aglutinación indirecta, Acs anti-cardiolipina y Acs anti-ß2GPI por ELISA, anticoagulante lúpico por métodos de rastreo y confirmatorios y Acs anti-DNAdc por inmunofluorescencia indirecta. Se obtuvo una alta prevalencia de Acs anti-cardiolipina: SAF 1º (97,5 por ciento) y SAF 2º (83,3 por ciento). Hubo diferencias significativas en la prevalencia de Acs anti-ß2GPI en SAF 1º con respecto a SAF 2º (90 por ciento vs 61,6 por ciento) (p<0,01). La asociación de Acs anti-DNAdc y Acs anti-cardiolipina fue de 89,7 por ciento. Se llegó a la conclusión de que los Acs anti-cardiolipina son los que se detectan con mayor frecuencia en pacientes con síndrome antifosfolípido independientemente de ser primario o secundario. Los Acs anti-ß2GPI serían una importante herramienta diagnóstica por ser más específicos. En pacientes con SAF 2º y LES la presencia de Acs anti-cardiolipina sería más frecuente en aquellos que cursan con Lupus activo