Lupus Anticoagulant-Hypoprothrombinemia Syndrome: Correspondence

Excerpt

To the Editor: I have read with great interest the article “Lupus anticoagulant-hypoprothrombinemia syndrome” by Bhowmick et al. [1]. In systemic lupus erythematosus (SLE), secondary antiphospholipid antibody syndrome (APLAS) may occur which is responsible for serological lupus anticoagulant (LA) and/or anticardiolipin (aCL) antibody positivity. Bleeding symptoms in a patient with LA may be caused by thrombocytopenia, as a manifestation of APLAS or SLE itself, or rarely, by hypoprothrombinemia caused by a coexistent specific autoantibody against prothrombin (Factor II) [2]. This antiprothrombin antibody does not inactivate prothrombin in contrast to acquired coagulation factor inhibitor seen in Hemophilia A, but causes accelerated clearance of prothrombin resulting in hypoprothrombinemia. The laboratory criterion for APLAS is either presence in plasma of aCL in moderate or high titre or LA on two or more occasions at least 6 wk apart [3]. In the index case, prolonged activated partial thromboplastin time (APTT) and prothrombin time (PT)/ increased International normalized ratio (INR) may indicate combined deficiency of Factor VII (extrinsic pathway) and any factor, in intrinsic pathway, or rarely, any factor deficiency in the common pathway i.e., Factor X Factor V, or Factor II. The antiprothrombin antibody is coexistent with LA in lupus anticoagulant–hypoprothrombinemia syndrome (LA-HPS). This antiprothrombin antibody leads to low prothrombin levels due to its quick clearance from plasma. The author mentioned that complete coagulation studies showed low thrombin level (Factor II assay 8.6%). It should be low prothrombin level. LA-HPS is a rare association with SLE [4]. …