Lupus anticoagulant in children – a confounding factor in diagnosis and targeted therapy

Abstract Introduction: Lupus anticoagulant (LAC) belongs to a heterogeneous group of antibodies directed against negatively charged phospholipid-binding proteins, inhibiting phospholipid-dependent reactions. We assessed the frequency, etiological background, clinical and biological expression as well as the appropriate management and outcome of LAC in a pediatric population. Patients and methods: We included 19 pediatric patients diagnosed with a positive LAC test during a period of 1 year. LAC detection was carried out according to the ISTH/SCC guidelines 2012. Coagulometric assays were performed in order to check for coagulation factor activities. The presence of specific inhibitors has been tested by the Bethesda assay. Results: LAC was positive in 0.4% of the patients monitored for increased activated partial thromboplastin time (aPTT) during the study period of 1 year. In contrast to the asymptomatic clinical image presented by the majority of our patients, the biological picture was dominated by an elevated aPTT (79 %), the aPTT ratio correlating significantly with the strength of LAC. In 58 % of the patients LAC became negative within 12 weeks, in another 4 (21%) patients within 20 weeks, whereas in 4 (21%) patients LAC remained positive throughout the follow-up. Conclusion: Albeit usually innocent in asymptomatic patients, LAC needs to be seriously taken into consideration from the diagnostic point of view in order to avoid dangerous therapeutic attitudes..