Elevated vWF Antigen Serum Levels Are Associated With Poor Prognosis, and Decreased Circulating ADAMTS-13 Antigen Levels Are Associated With Increased IgM Levels and Features of WM but not Increased vWF Levels in Patients With Symptomatic WM

Abstract

Background: Waldenström's macroglobulinemia (WM) is a rare malignancy characterized by bone marrow infiltration by lymphoplasmacytic cells and the presence of a monoclonal IgM paraprotein. The interactions of lymphoplasmacytic cells with other cells in their microenvironment, including mast cells and endothelial cells, support their survival and proliferation and can induce resistance to therapy. von Willebrand factor (vWF) plays a key role in primary hemostasis but is also a marker of endothelial "stimulation." High levels of vWF have been associated with an adverse prognosis in patients with symptomatic WM and might reflect the interactions between lymphoplasmacytic cells and other cells of their microenvironment.

Materials and methods: Considering vWF and ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) as markers of endothelial dysfunction and activation, we evaluated the prognostic importance of vWF and ADAMTS-13 antigen levels in the serum of patients with previously untreated symptomatic WM to validate vWF as a possible prognostic marker for progression-free and overall survival. We also validated the measurement of vWF in the serum instead of citrated plasma and investigated the possible correlations of ADAMTS-13 antigen levels with disease characteristics. The analysis included 42 patients with symptomatic WM and 19 matched healthy controls.

Results: The serum levels of vWF antigen provided significant prognostic information, and patients with levels ≥ 200 IU/dL had a very poor prognosis compared with patients with lower levels. The ADAMTS-13 antigen levels were decreased in WM patients and correlated with the IgM levels, β₂-microglobulin, and extent of bone marrow infiltration.

Conclusion: vWF levels measured in the serum could become an important prognostic marker in patients with WM and requires further investigation.

Keywords: Endothelial dysfunction; Waldenström's macroglobulinemia; von Willebrand factor.