| Abstract|| |
BACKGROUND: von Willebrand disease is a common inherited bleeding disorder caused by the deficiency of von Willebrand factor (vWF). The levels of vWF depend on several factors, including exercise, hormones, and ABO blood type. This study was planned to evaluate plasma vWF levels and factor VIII (fVIII) levels in healthy blood donors and its association with the ABO blood group.
AIMS: The aim of this study was to evaluate plasma vWF levels and fVIII levels in healthy donors and its association with the ABO blood group.
METHODS: This study was done in 2016 healthy adult blood donors. Complete history and relevant examination were done along with ABO and Rh (D) blood group typing, complete blood count, prothrombin time, activated partial thromboplastin time, vWF antigen (Ag) level, fVIII coagulant assay, and other tests for hemostasis.
STATISTICAL ANALYSIS USED: Data were expressed in proportions and mean, median, and standard deviation, respectively. An appropriate test of significance was applied. P < 0.05 was considered statistically significant.
RESULTS AND CONCLUSIONS: vWF level of donors ranged from 24 to 186 IU/dL with a mean of 96.31 IU/dL. Low vWF Ag level (below 50 IU/dl) was found in 2.5% of donors while 0.1% (2/2016) had level <30 IU/dL. O Rh (D)-positive blood group donors had the lowest vWF level (87.85 IU/dL), while ARh (D)-negative donors had the highest vWF level (117.27 IU/dL). fVIII level of the donor population ranged from 22% to 174%, with a mean of 98.82%. About 2.48% of donors had fVIII levels below 50%. There was a statistically significant correlation between fVIII level and vWF level (P < 0.001).
Keywords: ABO blood group, bleeding manifestation, factor VIII coagulant assay, von Willebrand factor
|How to cite this article:|
Agrawal N, Pahuja S, Sharma S. Von Willebrand factor levels in healthy blood donors and their association with blood group: A tertiary care hospital-based study. Asian J Transfus Sci 2023;17:28-33
|How to cite this URL:|
Agrawal N, Pahuja S, Sharma S. Von Willebrand factor levels in healthy blood donors and their association with blood group: A tertiary care hospital-based study. Asian J Transfus Sci [serial online] 2023 [cited 2023 Mar 21];17:28-33. Available from: https://www.ajts.org/text.asp?2023/17/1/28/370931
| Introduction|| |
Von Willebrand disease (vWD) is the most common inherited bleeding disorder caused by quantitative deficiency (Type 1 and Type 3) or qualitative defect (Type 2) of von Willebrand factor (vWF)., It has an estimated prevalence of 1% in the population worldwide.
vWF is a large multimeric plasma glycoprotein which plays a critical role in hemostasis. It initiates platelet adhesion and also transports and protects factor VIII (fVIII) from in vivo proteolysis. Plasma levels of vWF are influenced by several genetic and environmental factors, including exercise, hormones, ABO blood type, and age., Among all these factors, ABO blood group type exerts major quantitative effects on the plasma levels of the vWF-fVIII complex, with significantly lower levels of vWF and fVIII in O blood group individuals than nonO blood group individuals. Not much work has been done in India on the correlation of blood group and age with plasma vWF level. We planned a study to evaluate the vWF level of the healthy blood donor population and its association with the ABO blood group type.
| Methods|| |
This hospital-based cross-sectional study was done from November 2018 to March 2020. Two thousand and sixteen healthy adult donors who came for blood donation to Regional Blood Transfusion Center, Lady Hardinge Medical College, were recruited into the study. All the people who were on medications such as anticoagulants, Oral Contraceptive Pill (OCP), antiplatelet drugs, anticonvulsants, and antibiotics were excluded from the study and were also deferred from blood donation. The study was conducted after getting approval from the Institutional Ethics Committee and after taking informed written consent from the participants in the language they understand. Detailed personal and family history of hemorrhagic symptoms (epistaxis, easy bruising, menorrhagia, gum bleeding, etc.) was recorded in a predesigned performa (on the basis of a condensed MCMDM-1 bleeding questionnaire).
Blood samples were collected for: Complete blood count (CBC), ABO and Rh (D) blood group typing, prothrombin time (PT), activated partial thromboplastin time (aPTT), vWF: antigen (Ag), and fVIII coagulant assay. Just after venepuncture for blood donation, with the help of a vacutainer port of quadruple blood bag, 2.7 ml of blood was taken in citrate vacutainer (containing 0.3 ml of 3.2% trisodium citrate) and 2 ml of blood was taken in dipotassium ethylenediaminetetraacetic acid (EDTA) vacutainer.
Platelet poor plasma was prepared for vWF and fVIII test immediately by centrifuging citrated blood at 2000 g (relative centrifugal force) for 15 min. A CBC of the study group was performed on an EDTA blood sample on Sysmex KX 21 automated hematology analyzer [Figure 1]. PT and aPTT were determined on the same day using standard commercial PT/APTT reagents by Diagnostica Stago (France) using a fully automated Stago STA compact coagulation analyzer [Figure 2]. The remaining plasma was stored in separately labeled aliquots for vWF and fVIII tests and stored in the deep freezer at <−40°C.
Quantitative determination of vWF: Ag in plasma was done by the immunoturbidimetric method using the STA®-Liatest® vWF: Ag kit (Stago, France) [Figure 3]. The assay was based on the change in turbidity of latex microparticles coated with antibodies specific for vWF. The suspension was mixed with the test plasma whose vWF: Ag level was to be assayed. An Ag-antibody reaction takes place, leading to agglutination of the latex microparticles which induces an increase in turbidity of the reaction medium. This increase in turbidity was reflected by an increase in absorbance, which was measured photometrically. Coagulation assay for fVIII was done by STA®-Deficient VIII (Stago, France) [Figure 4]. The assay measured clotting time, in the presence of cephalin and activator, of a system in which all the factors are present and in excess (supplied by STA®-Deficient VIII) except fVIII which was derived from the sample being tested. Before performing these tests, the plasma samples were thawed in a water bath set at 37°C.
|Figure 3: STA® - LIATEST ® vWF: AG KIT, diagnostica stago (France). vWF: von Willebrand factor|
Click here to view
| Results|| |
A total of 2016 healthy blood donors attending the Regional Blood Transfusion Centre, Lady Hardinge Medical College and Associated Hospitals were enrolled in the study. The age of the study population ranged from 18 to 55 years, with a mean age of 30.40 years. The maximum number of donors (54.6%) belonged to the age group of 21–30 years. The majority of the donors were males contributing to 99.4% of total donors. None of the donors had any personal or family history of bleeding manifestation. All the donors had hemoglobin levels within the normal range (>12.5 g/dL). Platelet counts of the donors were also within the normal range.
The maximum number of donors belonged to BRh (D)-positive blood group (33.9%) while ABRh (D)-negative blood group constituted the least number of donors (0.7%).
PT was prolonged beyond the reference range in 1 out of 2016 donors. aPTT was abnormally prolonged in 5 out of 2016 donors. Both were corrected after mixing with pooled normal plasma in all these six donors, suggestive of clotting factor deficiency.
vWF levels of the donors ranged from 24 to 186 IU/dL with a mean of 96.31 IU/dL. Out of 2016 donors, 97.4% of the donors (1963/2016) had normal vWF levels (>50 IU/dL). Low vWF was present in 2.5% (51/2016) of the donors, while 2/2016 donors (0.1%) had vWF level <30 IU/dL (considered level for definitive diagnosis of vWD). There was a positive, statistically significant (P = 0.008) correlation between age and vWF level. For every 1 year increase in age, the vWF level increased by 0.36 IU/dL. No statistically significant difference was observed in vWF: Ag levels between both genders (P = 0.062). All the donors with subnormal vWF levels were males.
Donors with O Rh (D)-positive blood group had the lowest vWF level with a mean of 87.85 IU/dL, while ARh (D)-negative blood group donors had the highest vWF level with a mean of 117.27 IU/dL [Table 1]. vWF level of O blood group donors was significantly (P < 0.001) lower than nonO blood group donors (A, B, and AB) [Table 2]. However, no statistically significant difference was observed in vWF: Ag levels among nonO blood group donors (between A and B, B and AB, and A and AB). Rh (D)-negative donors had a significantly higher level of plasma vWF: Ag level than Rh (D)-positive donors (P = 0.001).
|Table 1: von Willebrand factor and factor VIII level in different ABO RhD blood groups of donors (n=2016)|
Click here to view
|Table 2: Comparison of von Willebrand factor and factor VIII level of donors with O and nonO blood groups (n=2016)|
Click here to view
We reevaluated the subgroup of donors with subnormal levels of vWF: Ag level for blood group and age distribution. About half of the donors with subnormal vWF levels belonged to blood group O contributing 47.2% of total donors, followed by B, A, and AB blood groups [Table 3].
|Table 3: Blood group distribution of donors with subnormal von Willebrand factor level (n=53)|
Click here to view
Donors with blood group A showed a significant correlation of plasma vWF: Ag level with age. The level of donors of the older age group was significantly higher than younger donors of the same blood group.
fVIII level of the donor population ranged from 22% to 174%, with a mean of 98.82%. Out of 2016 donors, 2.48% of donors had fVIII levels below 50%. There was no statistically significant difference in fVIII level among donors of different age groups.
The lowest plasma fVIII level was found in the donors of blood group O, while A blood group had the highest level, followed by B and AB blood group donors. fVIII level of O blood group donors was significantly lower than nonO blood group donors (P = 0.001) [Table 2].
The mean fVIII level in the donors with the subnormal level of vWF was 40.92%. Both the donors with vWF levels <30 IU/dL, also had low fVIII levels (<50%) along with prolonged aPTT (>34.5 s). However, among 51 donors with vWF levels of 30–50 IU/dL (low vWF), 20 donors had low fVIII with 1 donor having prolonged aPTT while the rest 31 donors had normal fVIII levels [Table 4].
|Table 4: Distribution of donors with subnormal von Willebrand factor levels according to factor VIII levels|
Click here to view
There was a positive, statistically significant correlation between fVIII level and vWF level (P < 0.001). An increase of 0.09 IU/dL in the vWF level leads to 1% increase in the fVIII level [Figure 5].
|Figure 5: Correlation between factor VIII level and vWF level. vWF: von Willebrand factor|
Click here to view
| Discussion|| |
vWD is a common bleeding disorder caused by deficiency or dysfunction of vWF. It is reported worldwide as one of the most common hereditary bleeding disorders. vWF levels exhibit a high degree of variation within different populations, ranging from 50 to 200 IU/dl. Some researchers have reported the association of the ABO blood group with plasma vWF levels. The effect of the ABO blood group on plasma vWF: Ag levels may be due to altered rates of vWF synthesis or secretion by endothelial cells of a different ABO genotype. Alternatively, the effect of ABO on plasma vWF: Ag levels may be due to different rates of vWF clearance from the plasma in vivo.
In the present study, we evaluated the influence of ABO blood group type, age, and gender on the plasma levels of vWF: Ag. Our study shows that the ABO blood group has a statistically significant correlation with vWF: Ag plasma levels. Blood group O donors had the lowest mean vWF level, while AB blood group donors had the highest mean vWF level, and the difference between the two groups was statistically significant. Among nonO blood groups, there was no statistically significant difference in mean vWF: Ag levels between A, B, and AB blood groups.
Gill et al. in a study on 1101 healthy donors reported that individuals with blood group O had the lowest mean vWF: Ag level (74.8 U/dL), followed by group A (105.9 U/dL), group B (116.9 U/dL), and AB (123.3 U/dL) blood group donors. In the study conducted by Souto et al., the lowest mean values of vWF: Ag (77.3% ± 27%) were observed in subjects with type O blood group, and the highest vWF: Ag values (136.7% ± 33%) corresponded to type AB blood group subjects. vWF: Ag level was found to be significantly lower in the O blood group than in the nonO blood group (A, B, and AB). Similar results have been reported in other populations – Nigeria, Turkey, Italy, Georgia, Africa, and China. However, in the study done by Coppola et al., there was no significant difference in vWFlevels between Group O and nonO centenarians. Comparative evaluation of vWF level of O and nonO blood group subjects in various studies is shown in [Table 5].
|Table 5: von Willebrand factor level of O and nonO blood group subjects in various studies|
Click here to view
In our study, we found a positive correlation of age with plasma vWF level as an increase of vWF level by 0.36 IU/dL with every 1 year increase in age. The vWF level of donors of age group <20 years and 21–30 years was significantly lower than the level of donors of 41–50 years of age. Coppola et al. in a study conducted in 2003 found that vWF: Ag levels were higher in centenarians than in subjects of age <100 years. However, study by Akpan et al. showed no statistically significant correlation between plasma vWF: Ag concentration and the age of the blood donors (P = 0.9664). Plasma vWF levels showed no significant difference between both the gender groups in our study. This observation in our study was similar to the study of Rodeghiero et al. and Gill et al. where male and female adults had almost similar vWF levels.
Donors with the O blood group had mean fVIII levels significantly lower than nonO blood group donors with no significant association fVIII levels with age. Plasma vWF level showed a positive, statistically significant correlation with fVIII level (P < 0.001). In a study conducted by Souto et al., the lowest mean values of fVIII: C (131.8%) were observed with type O blood group subjects, and the highest fVIII: C values (170.9%) corresponded to AB blood group subjects. Wang et al. in a study conducted on 290 healthy volunteer blood donors observed that the plasma fVIII level of O blood group donors was significantly lower than the level of nonO blood group donors. They also observed that the mean fVIII level of donors of <40 years of age (78.2%) was significantly lower than the level of the donor of >50 years of age (110.3%).
There is a paucity of studies on the level of vWF in the healthy Indian population and its association with ABO blood group types. Ambika et al. assessed vWF in 394 healthy blood and apheresis donors in Southern India and found that VWF: Ag level was significantly lower for O group than nonO group individuals (P = 0.001, F = 71.707). Few studies have been performed on vWF levels in patients presenting with menorrhagia, epistaxis, or other hemorrhagic symptoms.,, Research in this will enhance our knowledge regarding subclinical deficiency of vWF and the association of plasma vWF levels with different ABO blood group types.
| Conclusion|| |
Our study has shown that ABO blood group and age but not gender of an individual have a significant influence on plasma levels of vWF: Ag while fVIII level is influenced by blood group but not the age of the individual. A positive, statistically significant correlation was observed between plasma vWF level and fVIII level (P < 0.001) in our study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Kumar S, Kishore R, Gupta V, Jain M, Shukla J. Prevalence and spectrum of von Willebrand disease in Eastern Uttar Pradesh. Indian J Pathol Microbiol 2010;53:486-9.
] [Full text]
Lillicrap D. von Willebrand disease: Advances in pathogenetic understanding, diagnosis, and therapy. Blood 2013;122:3735-40.
Sukhu K, Poovalingam V, Mahomed R, Giangrande PL. Ethnic variation in von Willebrand factor levels can influence the diagnosis of von Willebrand disease. Clin Lab Haematol 2003;25:247-9.
Mohanty D, Shetty S. Von Willebrand disease : An update. J Blood Disorders Transf 2014;5:238.
Albánez S, Ogiwara K, Michels A, Hopman W, Grabell J, James P, et al.
Aging and ABO blood type influence von Willebrand factor and factor VIII levels through interrelated mechanisms. J Thromb Haemost 2016;14:953-63.
Stakiw J, Bowman M, Hegadorn C, Pruss C, Notley C, Groot E, et al.
The effect of exercise on von Willebrand factor and ADAMTS-13 in individuals with type 1 and type 2B von Willebrand disease. J Thromb Haemost 2008;6:90-6.
O'Donnell J, Boulton FE, Manning RA, Laffan MA. Amount of H antigen expressed on circulating von Willebrand factor is modified by ABO blood group genotype and is a major determinant of plasma von Willebrand factor antigen levels. Arterioscler Thromb Vasc Biol 2002;22:335-41.
Trasi S, Shetty S, Ghosh K, Mohanty D. Prevalence and spectrum of von Willebrand disease from western India. Indian J Med Res 2005;121:653-8.
Douleh EA, Numair NA, Albanyan A, Alsuliman A, Bayoumi N, Owaidah T. Prevalence of von willebrand disease among university students in Riyadh, Saudi Arabia. J Appl Hematol 2018;9:136-9.
Lanke E, Johansson AM, Halldén C, Lethagen S. Genetic analysis of 31 Swedish type 1 von Willebrand disease families reveals incomplete linkage to the von Willebrand factor gene and a high frequency of a certain disease haplotype. J Thromb Haemost 2005;3:2656-63.
Gill JC, Endres-Brooks J, Bauer PJ, Marks WJ Jr., Montgomery RR. The effect of ABO blood group on the diagnosis of von Willebrand disease. Blood 1987;69:1691-5.
Souto JC, Almasy L, Muñiz-Diaz E, Soria JM, Borrell M, Bayén L, et al.
Functional effects of the ABO locus polymorphism on plasma levels of von Willebrand factor, factor VIII, and activated partial thromboplastin time. Arterioscler Thromb Vasc Biol 2000;20:2024-8.
Akpan IS, Essien EM. Measurement of Von Willebrand factor antigen levels in a Nigerian population : Relative effects of ABO blood group, age, gender and ethnic differences. IJSRM Hum 2017;8:58-69.
Akin M, Balkan C, Karapinar DY, Kavakli K. The influence of the ABO blood type on the distribution of von Willebrand factor in healthy children with no bleeding symptoms. Clin Appl Thromb Hemost 2012;18:316-9.
Rodeghiero F, Castaman G, Dini E. Epidemiological investigation of the prevalence of von Willebrand's disease. Blood 1987;69:454-9.
Miller CH, Dilley A, Richardson L, Hooper WC, Evatt BL. Population differences in von Willebrand factor levels affect the diagnosis of von Willebrand disease in African-American women. Am J Hematol 2001;67:125-9.
Wang Z, Dou M, Du X, Ma L, Sun P, Cao H, et al.
Influences of ABO blood group, age and gender on plasma coagulation factor VIII, fibrinogen, von Willebrand factor and ADAMTS13 levels in a Chinese population. PeerJ 2017;5:e3156.
Coppola R, Mari D, Lattuada A, Franceschi C. Von Willebrand factor in Italian centenarians. Haematologica 2003;88:39-43.
Ambika PL, Kar R, Basu D, Kulkarni RG. Influence of ABO blood group on Von Willebrand factor antigen level in normal individuals: A cross-sectional study from southern India. Indian J Hematol Blood Transfus 2021;37:505-6.
Gupta PK, Charan VD, Saxena R. Spectrum of Von Willebrand disease and inherited platelet function disorders amongst Indian bleeders. Ann Hematol 2007;86:403-7.
Saxena R, Gupta M, Gupta PK, Kashyap R, Choudhry VP, Bhargava M. Inherited bleeding disorders in Indian women with menorrhagia. Haemophilia 2003;9:193-6.
C/o Dr. Rajendra Diagnostic Center, Shop No. 44, Near Trauma Center, Opposite Vijay Cinema MGM Government Hospital, Hanumangarh - 335 513, Rajasthan
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]