Rituximab in lupus anticoagulant hypoprothrombinemia syndrome: A case report.

Background: Lupus anticoagulant hypoprothrombinemia syndrome (LAHPS) is a rare autoimmune condition characterized by acquired prothrombin (FII) deficiency associated with antiphospholipid syndrome (APS) and life-threatening bleeding. We present the case of a 34-year-old woman with heavy menstrual bleeding (HMB), positive Lupus anticoagulant (LA) test, and high titer anticardiolipin antibodies Immunoglobulin G (ACA IgG) and anti-β2 glycoprotein I antibodies IgG (antiB2GPI IgG). Severe iron deficiency anemia necessitated recurrent blood transfusions and intravenous iron infusions from 2018 to 2021.

Results: In January 2022, she was admitted to our clinic. Von Willebrand disease screening and platelet function analysis (PFA100) were normal. FII and FIX deficiencies were detected, without factor IX inhibitors. Anti-phosphatidylserine/prothrombin antibodies were confirmed by Padua University lab. To reduce antibody titers and menstrual bleeding, immunosuppressive therapy (Rituximab 375 mg/m2 weekly ×4 weeks) and hormonal therapy (desogestrel 75 mcg/day) were initiated.

Conclusion: After 1-year, complete remission of clinical symptoms was achieved, with normalization of FII and FIX values and moderate reduction of aPS/PT titers, especially IgM isotype.