Abstract Number: PB1580
Meeting: ISTH 2020 Congress
Background: VWF multimers testing is an integral part of the diagnostic process on VWD. By this way, low (LMWM), intermediate (IMWM), high (HMWM) and ultra-high (UHMWM) molecular weight multimers can be estimated.
Aims: To determine if VWF multimeric profile obtained by agarose electrophoresis with gel immunofixation in semi-automatic system (Hydragel 5) and agarose gel electrophoresis reference methods are comparable.
Methods: Samples (n=24): 4 acquired VW syndrome (AVWS) from myeloproliferative syndrome with thrombocytosis (MPS-T), 6 VWD type 1, 9 type 2 (confirmed by molecular biology), 1 probably type 2N, 2 not classified type 2, and 2 from Thrombotic Thrombocytopenic Purpura (TTP).
Semiautomatic method: Electrophoresis followed by immunofixation using Hydragel 5 von Willebrand Multimers kit in HYDRASYS 2 instrument (Sebia).
Standard method: Discontinuous SDS-electrophoresis in agarose gels followed by inmunofixation using a polyclonal rabbit anti-Human VWF and polyclonal swine anti-rabbit inmunoglobulins biotinylated, revealed with 4Cl-1-Naftol. Multimeric profile: analyzed by ImageQuant TL 8.1 (GE Healthcare).
Results: Results are shown in tables 1 and 2.
Each gel processing was completed in one working day and its visualization was clear. AVWS showed decreased HMWM. VWD type 1 showed normal multimeric profile. UHMWM were detected in TTP. Results of VWD type 2A, 2B and 2M are shown in table 2. The unclassified VWD type 2 samples showed presence of all multimers in one and slightly decreased HMWM in the other.
Conclusions: All MPS-T AVWS presented decreased HMWM. Samples from VWD type 1, 2A, 2B, and TTP presented full agreement of multimeric profile between methods.
In VWD 2M samples there was also agreement, even in the sample PMC with an unusual multimeric profile in which only semi quantitative estimation of HMWM showed slightly differences. The semiautomatic method seems to be a useful and appropriate method for VWF multimeric profile screening in Hemostasis clinical laboratories.
|Type of sample||Patient||VWF:Ag (%)||VWF:RCo (%)||VWF:RCo/ VWF:Ag ratio||Multimeric Profile|
|Reference method||Hydragel 5|
|AVWS MPS-T||n=4||94-114||32-55||0.3-0.48||–||Slightly decreased HMWM Slightly increased LMWM and IMWM|
|VWD type 1||n=6||33-58||32-45||0.6-0.85||Normal||Normal|
|Probably VWD type 2N||n=1||95 (FVIII: 33%)||77||0.77||–||Normal|
|TTP||BT||56||79||1.4||52% of UHMWM||UHMWM present|
|TTP||FM||156||157||1||31% of UHMWM||UHMWM present|
[Table 1: results of samples of VWD type 1, AVWS, TTP and a probable VWD type 2N]
|Type of sample||Patient||VWF:Ag (%)||VWF:RCo (%)||VWF:RCo/ VWF:Ag ratio||Mutation||Multimeric Profile Reference method||Multimeric Profile Hydragel 5|
|VWD type 2A||SC||70||<5||0.06||Heterozygous p.Arg1597Trp||Absence HMWM Very decreased IMWM Increased LMWM||Absence HMWM Very decreased IMWM Increased LMWM|
|VWD type 2A||EC||44||<10||0.20||Heterozygous p.Gly1631Asp||Absence HMWM Very decreased IMWM Increased LMWM||Almost absence HMWM Very decreased IMWM Increased LMWM|
|VWD type 2M||ZC||17||<10||0.53||Heterozygous p.Arg1374Cys||All multimers present but slightly decreased||Moderate decrease HMWM Slightly decreased IMWM Increased LMWM|
|VWD type 2M||PMC||21||<10||0.43||Homozygous p.Glu1549Lys||Decreased HMWM Slightly decreased IMWM Increased LMWM||Very decreased HMWM Slightly decreased IMWM Increased LMWM|
|VWD type 2M||SA||73||10||0.14||Heterozygous p.Thr1468Ile||Normal but Slightly increased LMWM||Slightly decreased HMWM Slightly increased LMWM|
|VWD type 2M||AB||21||<5||0.19||Heterozygous p.Arg1374Cys||All multimers present with low definition between mers||All multimers present with low definition|
|VWD type 2B||MC||71||26||0.37||Heterozygous p.Arg1306Trp||Absence of HMWM||Decreased HMWM Increased LMWM and IMWM|
|VWD type 2B||MK||41||57||1.39||Heterozygous p.Pro1266Leu||Normal||Normal|
|VWD type 2B||GA||75||38||0.51||Homozygous p.Val1316Met||Absence of HMWM||Very decreased HMWM Slightly increased LMWM|
[Table 2 Results of 9 samples of VWD type 2 previously classified]
To cite this abstract in AMA style:López MS, Paiva J, Woods AI, Saez MS, Barrera LH, Privitera V, Chuliber F, Villagra Iturre M, Penchasky D, Sorroche P, Oyhamburu J, Martinuzzo M, Sánchez Luceros A. Comparison of von Willebrand Factor (VWF) Multimeric Profile Obtained by a Commercial Electrophoretic Test (Hydragel 5 von Willebrand Multimers) and Classical Home-made with a Discontinuous 1% Agarose Gel Electrophoresis [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/comparison-of-von-willebrand-factor-vwf-multimeric-profile-obtained-by-a-commercial-electrophoretic-test-hydragel-5-von-willebrand-multimers-and-classical-home-made-with-a-discontinuous-1-agarose/. Accessed January 23, 2022.
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