IgA inhibitor to factor VIII/von Willebrand factor

[Acquired von Willebrand syndrome: from diagnosis to treatment]

Acquired von Willebrand syndrome is a rare bleeding disorder, which has been related in various diseases including lymphoproliferative disorders or autoimmune diseases. Its diagnosis is an important step before treatment of patients and particularly in case of bleeding. We report four cases from Caen Hemophilia Treatment Center, diagnosed and treated from 1999 to 2008. Mucocutaneous bleeds in every case were the same as in hereditary von Willebrand disease. All patients had no personal or family history of bleeding. Phenotype was identified as type 2 von Willebrand disease with a loss of high molecular weight multimers. Anti-von Willebrand factor inhibitor screening was positive for three patients. The etiological diagnosis was one chronic lymphocytic leukaemia, two monoclonal gammapathies of undetermined significance (MGUS) and one undetermined case. The management of patients need two stages: first infusions of factor von Willebrand/factor VIII concentrates to stop bleeds, then treatment of the underlying disease such as chemotherapy, corticotherapy and treatment with high doses of polyvalents immunoglobulins. In every case, treatment was effective and improved patient's quality of life.

A new ELISA assay for diagnosis of acquired von Willebrand syndrome

The pathophysiology of acquired von Willebrand syndrome (AVWS), a rare bleeding disorder, is not fully understood. Circulating antibodies to Von Willebrand factor (VWF) are found in patients with AVWS associated with lymphoproliferative disorders but these autoantibodies are difficult to detect with routine laboratory tests and neutralisation assays. We have developed a simple enzyme-linked immunosorbent assay (ELISA) to detect serum antibody binding to VWF protein immobilized on polystyrene plates. Ten patients with AVWS were studied, eight of whom also had lymphoproliferative disorders. We found antibodies in eight patients; all of them were positive for IgG and five were also positive for IgM. This simple method appears to be more sensitive than functional assays, which failed to identify two of the patients who were positive with the ELISA. In conjunction with other tests, this ELISA method may be useful for demonstrating the immunological mechanism underlying some cases of AVWS. Such patients would qualify for intravenous immunoglobulin therapy, which can correct the clotting disorder.

Acquired von Willebrand's disease: a concise review

Acquired von Willebrand's disease (AvWD), an adult-onset bleeding diathesis, has most commonly been found in patients with an underlying lymphoproliferative disease or monoclonal gammopathy. Other malignancies, autoimmune diseases, hypothyroidism, and drugs have also been associated with AvWD. We have included an illustrative case history of a patient with a bleeding diathesis consistent with AvWD and a monoclonal gammopathy who required emergent cardiac surgery. Our review of the literature determined that most cases of AvWD are due to a circulating antibody that combines with the high molecular weight multimers (HMWM) of von Willebrand factor (vWF). These vWF multimer-antibody complexes are subsequently cleared from the circulation either by the reticuloendothelial system or by adsorption onto tumor cells. Clearance of the HMWM of vWF thus results in extremely low functional levels and variable antigenic levels. Mixing studies which are traditionally used to diagnose factor inhibitors are useful only if removal of vWF-antibody complexes can be accomplished in vitro. Treatment with intravenous immunoglobulin has recently been shown to be the most effective therapy for patients with an underlying lymphoproliferative disorder or monoclonal gammopathy. This therapeutic strategy is based on the observed immune complex clearance phenomenon that appears to be operative in most cases. Other AvWD-associated diseases require treatment specifically directed at the underlying disorder.

Acquired von Willebrand disease associated with free lambda light chain monoclonal gammopathy, normal bleeding time and response to prednisone

We report a case of acquired von Willebrand's syndrome with severe gastrointestinal bleeding and associated free monoclonal lambda light chains. The patient had a rapid sustained clinical and laboratory response to the administration of prednisone. Of note in this patient was the occurrence of angiodysplasia which has previously been reported in association with acquired von Willebrand's syndrome. No inhibitors of VWF:Ag, VWF:RCoF, or factor VIII:C were detected by mixing studies and the bleeding time was normal. Very few high molecular weight von Willebrand multimers were present prior to prednisone; however, the pattern reverted to a normal distribution following treatment. In appropriate patients with acquired von Willebrand's syndrome and monoclonal para-proteins, a trial of prednisone may be indicated.