Quantification and Facilitated Comparison of von Willebrand Factor Multimer Patterns by Densitometry

Abstract

Platelet satellitism surrounding polymorphonuclear neutrophils has been observed almost exclusively in EDTA-treated blood at room temperature. The mechanism underlying this phenomenon is not understood fully. We report a case of platelet rosetting around atypical lymphocytes in peripheral blood smears made from EDTA-treated and untreated blood. Flow cytometry of the peripheral blood sample and immunohistochemical stains of the subsequent bone marrow biopsy specimen revealed a monoclonal B-cell population positive for CD5, CD20, and cyclin D1 and negative for CD3 and CD23; cytogenetic findings revealed a complex karyotype that included t(11;14). These findings were consistent with mantle cell lymphoma. To our knowledge, the finding of platelet satellitism involving mantle cell lymphoma cells in peripheral blood has not been reported previously.

Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

“…Following treatment with the VWF concentrates used in this study, only a single type 1 VWD patient, had HMWM within normal limits. Not all high purity human VWF concentrates fully restore HMWM to normal levels,10 although Haemate P has previously been demonstrated to produce a significant increase to HMWM,24 this was not observed in our cohort. Further studies are needed to investigate post treatment samples using H5VWM.…”

“…In‐house VWF multimers (IHVWM) may be performed using sodium dodecyl sulphate (SDS) agarose gel electrophoresis, often followed by Western blotting, then visualization by methods including via radioactive Iodine (I 125 ) autoradiography, chemiluminescence,7 infrared fluorescent imaging,8 or Alkaline Phosphatase (AP) 9. Densitometry of the agarose gels may be performed to aid interpretation of the multimer pattern 10. Interpretation of densitometry is also not standardized between laboratories; some report peaks 1‐3 to represent the LMWM, 4‐5 the intermediate molecular weight multimers (IMWM), and peaks 6 and above represent the HMWM,11 while others report peaks 1‐5 as LMWM, 6‐10 as IMWM, and peaks 10 and above as HMWM 9…”

Evidence for a role of anti-ADAMTS13 autoantibodies despite normal ADAMTS13 activity in recurrent thrombotic thrombocytopenic purpura

“…VWF multimer analysis was performed on 1.7% sodium-dodecyl sulfate-agarose (Type VII, LGT; Sigma-Aldrich, St Louis, MO, USA) gels according to Budde et al 17 The patient's multimer patterns were compared to the reference pattern of normal human Anti-ADAMTS13 autoantibodies and normal ADAMTS13 activity in TTP haematologica | 2012; 97 (2)plasma run on the same gel by scanning densitometry 18 and visual comparison by one of us (UB), blinded for corresponding ADAMTS13 activity and disease state. To assess endogenous VWF proteolysis semi-quantitatively, VWF satellite bands were classified as being increased, normal, decreased or absent.…”

Increased von Willebrand factor antigen and high molecular weight multimers in sickle cell disease associated with nocturnal hypoxemia

“…Blots were then incubated with rabbit anti-human vWF polyclonal antibody (Dako, California) followed by anti-rabbit IgG-HRP conjugate (GE Healthcare, New Jersey), developed using ECL chemiluminescence (GE Healthcare, New Jersey). X-ray images were scanned and analyzed [16]. Optical density values representing the concentrations of vWF multimers of different molecular weights were plotted as densitographs using NIH ImageJ software (Table); individual peaks on the densitographic plot were identified as being separated by a clear trough between 2 adjacent peaks.…”