A woman with systemic lupus erythematosus, multiple pregnancy complications, and cerebral infarction who was only positive for phosphatidylserine-dependent antiprothrombin antibodies

A woman with systemic lupus erythematosus (SLE) had a history of two abortions before the 10th week, two foetal deaths with normal morphology, and one premature before the 34th week with early-onset hypertensive disorder of pregnancy (HDP) and placental dysfunction. Although she did not have any conventional antiphospholipid antibodies (aPLs), antiphospholipid syndrome (APS) was strongly suspected based on her obstetric history and renal biopsy findings consistent with aPL-associated nephropathy (APLN). Eventually, she was found to be positive for phosphatidylserine-dependent antiprothrombin antibodies (aPS/PTs). A healthy baby was born with anticoagulation and intravenous immunoglobulin (IVIG) therapy during pregnancy. aPS/PT titres gradually increased after delivery. Cerebral infarction occurred at 9 years after birth. If APS is clinically suspected but the antibodies included in the classification criteria for APS are all negative, we should consider an association with unconventional aPLs and manage according to APS.