Abstract
Background:
It is well established that ABO and rhesus (Rh) genes and phenotypes vary widely between ethnic groups and both within and between geographical areas. The aim of this study was to determine the distribution of ABO and Rh blood groups in Kurds and to compare it with those of other populations.
Subjects and methods:
The study included blood grouping of total population of 53,234 whose ABO and Rh blood groups were determined by standard methods during a period of about 5 years (2005–2009).
Results:
The most prevalent blood group was O (37.16%), followed by blood groups A (32.47%) and B (23.84%), whereas the least prevalent blood group was AB (6.53%). The majority 91.73% were Rh positive, and 8.27% were Rh negative. Data showed that among the Rh-positive individuals, 34.03% were O, 29.99% were A, 21.69% were B, and 6.02% were AB. Break up of the Rh negatives showed that 3.13% were group O, 2.48% were A, 2.15% were B, and 0.51% were AB.
Conclusion:
Blood group O is the commonest blood group in, followed by A, B, and AB. More than 91% of the study population is Rh positive. Also, we can conclude that distribution of ABO and Rh blood groups in Kurds, in addition to being close to the mean of the world’s population, is closest to Iranians, with similar trend to the neighboring countries, and appears to be intermediate between eastern (Asian) and western European (Caucasian) data.
Keywords: ABO, rhesus, blood group, Kurds
Introduction
ABO blood group was discovered by Karl Landsteiner during early experiments with blood transfusion in 1901, for which he received the Nobel Prize 30 years later, and in cooperation with Alexander S Wiener, the rhesus (Rh) group was discovered in 1937.1 Even after 100 years, the single most important test performed in blood banking services is determination of ABO blood groups to avoid morbidity and mortality.2
Blood classification into groups is based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). Some of these antigens are also present on the surface of other types of cells and body secretions like saliva, sweat, semen, serum, tears, urine etc,3 which are used in forensic investigations. Several of these RBC surface antigens that stem from one allele (or very closely linked genes) collectively form a blood group system. Blood groups are genetically determined and exhibit polymorphism in different populations. A total of 30 human blood group systems are now recognized by the International Society of Blood Transfusion.4 Blood groups are inherited from both parents. The ABO blood types are controlled by a single gene located on the long arm of the ninth chromosome with 3 alleles: i, IA, and IB. IA and IB alleles are dominant over i, expressing a special dominance relationship (codominance), which means that type A and type B parents can have an AB-type child and O-type child if they are both heterozygous (IBi, IAi).5 ABO blood groups are the most investigated blood group system, and owing to ease of identifying their phenotypes, they have been used as genetic markers of populations. It is well established that differences in ABO blood groups exist, both within and among ethnic groups and by geographical area.6,7 Some variations may even occur in different areas within one small country.8
It is interesting to note that the distribution of ABO and Rh blood groups varies from race to race; therefore, the distribution of the blood groups A, B, O, and AB varies across the world according to the population and within human subpopulations, eg, in United Kingdom, the distribution of blood type frequencies in the population still shows some correlation to the distribution of placenames and to the successive invasions and migrations, including Vikings, Danes, Saxons, Celts, and Normans, who contributed the morphemes to the placenames and the genes to the population.9
Blood group distribution in different groups of population is important in health care and blood transfusion.10 Clinically, the two most significant blood group systems are ABO and Rh. Knowing of phenotype distribution of ABO system in a given population is important for planning procurement of blood supplement and associated diseases with blood group11 and to know if any significant phenotype dispersion is present when comparing with other population.
Almost always, an individual has the same blood group, but very rarely, an individual’s blood type changes through addition or suppression of an antigen, eg, in malignancy12 or in autoimmune diseases.13
When the rate of Rh positive is considered, varying percentages were reported in various races and populations: Caucasians (85%),7 African blacks (94%),14 Asians (99%),7 Arabians (91%),15 and Europeans with their descents (84%).16
To the best of our knowledge, there is no recent published study available on the distribution of ABO and Rh blood groups in Kurds (the native inhabitants of Mesopotamia). We designed this study to find out the frequency of ABO and Rh (D) phenotypes in Kurds of Iraq.
Subjects and methods
This study was carried out over a period of 5 years (2005–2009). The study population included a total of 53,234 apparently healthy subjects; 28,379 were men, and 24,855 were women. Their age ranged between 18 and 46 years (mean, 27.4 ± 6.2). The majority of study population were from attendants of Ma’moon Al-Dabbagh Health Centre laboratory for health screening and counseling before marriage and Hawler Teaching Hospital Laboratory for health screening and blood grouping, which is mandatory for various purposes, such as army recruitment, pre-employment health screening, and screening for driving license. This to a great extent excluded individuals with chronic illnesses, eg, diabetes mellitus, peptic ulcers, and malignancies.
All subjects were of known Kurdish ethnicity tribes from different provinces of Kurdistan Region of Iraq; Erbil, Duhok, Sulaymani, and Kirkuk, who were identified by their national Iraqi ID cards. The blood samples of the study population were typed by slide method, using ABO and Rh (D) Typing Antisera, Biotec Laboratories, United Kingdom. Manufacturer’s procedural instructions were followed. Results were compared with similar group prevalence studies from neighboring countries and world ethnic groups and races.
Results
The prevalence of O, A, B, AB, and Rh phenotypes is shown in Table 1. The most common blood group was O (37.16%), followed by blood groups A (32.47%) and B (23.84%). Blood group AB occurred at lowest prevalence (6.53%). The prevalence of the ABO phenotypes linked with Rh phenotype was O+ (34.03%), followed by A+ (29.99%), B+ (21.69%), and AB+ (6.02%). The lowest prevalence was that of AB − (0.51%) (Table 2). The difference in the pattern of blood groups O, A, B, and AB in men and women was inconsequential.
Table 1.
Prevalence of the phenotype of ABO and Rh (D)
| Phenotype | Men | % | Women | % | Total | % |
|---|---|---|---|---|---|---|
| (I) ABO phenotype | ||||||
| A | 8,946 | 31.52 | 8,337 | 33.54 | 17,283 | 32.47 |
| B | 6,793 | 23.94 | 5,900 | 23.74 | 12,693 | 23.84 |
| AB | 2,067 | 7.28 | 1,408 | 5.66 | 3,475 | 6.53 |
| O | 10,573 | 37.26 | 9,210 | 37.06 | 19,783 | 37.16 |
| Total | 28,379 | 100 | 24,855 | 100 | 53,234 | 100 |
| (II) Rh (D) phenotype | ||||||
| Rh (+ve) | 26,170 | 92.22 | 22,663 | 91.18 | 48,833 | 91.73 |
| Rh (−ve) | 2,209 | 7.78 | 2,192 | 8.82 | 4,401 | 8.27 |
| Total | 28,379 | 53.31 | 24,855 | 46.69 | 53,234 | 100 |
Table 2.
Prevalence of ABO and rhesus blood groups in Kurds
| ABO blood group | Rh factor (D) | No | Prevalence | Total |
|---|---|---|---|---|
| A | Positive | 15,965 | 29.99 | 32.47 |
| A | Negative | 1,318 | 2.48 | |
| B | Positive | 11,548 | 21.69 | 23.84 |
| B | Negative | 1,145 | 2.15 | |
| AB | Positive | 3,204 | 6.02 | 6.53 |
| AB | Negative | 271 | 0.51 | |
| O | Positive | 18,116 | 34.03 | 37.16 |
| O | Negative | 1,667 | 3.13 | |
| Total | Positive | 48,833 | 91.73 | 100 |
| Total | Negative | 4,401 | 8.27 |
Discussion
This study has determined the distribution of ABO and Rh (D) blood groups in Kurds at Kurdistan Region of Iraq in both sexes. Blood group of donors was not included to avoid a possible bias, as blood group O+ is regarded, in our country and some other countries, as a generous and more precious blood group encouraging more donation,17 and differences in blood group prevalence between general population and blood donors are obvious in some other studies.18 Also, the blood donation system in Iraq differs from many other countries in that the family and relatives of the recipient are responsible to insure blood units of the same recipients’ blood group available for transfusion, with its consequences in amplification of the number of donations of high incidence blood groups like group O, A, and Rh positive and low incidence of donation of less frequent blood groups like B, AB, and Rh negative, which falsely decrease its incidence more.
There were no significant differences in both ABO and Rh blood groups in men and women. This is because blood groups are of autosomal inheritance, thus, the frequencies are not different in both sexes, and, therefore, in blood group studies from all populations, blood groups are reported for men and women together. The marked differences between this study and a previous study on Kurds in Baghdad19 most probably can be attributed to a possible sampling error and the smaller size of the study population as Kurds are only forming about 5% of Baghdad population, whereas in Kurdistan region, Kurds are forming more than 95% of population.
Populations across the globe differ in the distribution of their blood group phenotypes (Table 3). In this study population, the frequency of blood group O was higher than A, followed by B, and the lowest was AB. These results were very close to a previous study on a smaller population of Iraqis (not Kurds).6
Table 3.
Prevalence of ABO phenotype of Kurds compared with neighboring countries and some other populations
| People group | O | A | B | AB |
|---|---|---|---|---|
| Iraq (non-Kurds)6 | 36 | 30 | 26 | 8 |
| Saudi Arabia24 | 51 | 26 | 19 | 4 |
| Kuwait21 | 44 | 27 | 24 | 5 |
| Jordan23 | 37 | 38 | 18 | 7 |
| Iran20 | 35 | 33 | 23 | 9 |
| Syria27 | 38 | 46 | 13 | 3 |
| Turkey26 | 32 | 46 | 15 | 7 |
| Asians (eg, India)25 | 39 | 23 | 33 | 5 |
| African blacks (eg, Nigeria)14 | 53 | 24 | 20 | 3 |
| Caucasian24 | 47 | 41 | 9 | 3 |
| Europeans16 | 43 | 40 | 12 | 5 |
| World’s population28 | 41 | 32 | 22 | 5 |
| Kurds (this study) | 37 | 32 | 24 | 7 |
Also, more probably, our results were close to many studies in Iran20 because both Iranians and Kurds (ie, ancient Medes) and Iraqis in general share the same history of the area. Results of this study have some similarity, but less close trends as seen in some of the neighboring Arab countries, eg, Kuwait,21 Saudi Arabia,22 and Jordan.23 These trends were also observed in populations of other ethnicity like Caucasian,24 Blacks,14 and Europeans.16 In many Asian populations, there is an increase in the prevalence of group B, eg, India and Malaysia.25 Our results were not comparable to the situation seen in the neighboring Turkey26 and Syria,27 with higher prevalence of group A.
Rh (D) positive frequency (91.73%) in this study was similar to some neighboring Arabian countries, eg, Saudi Arabia (91.22%),15 Arians (91.7%),25 and Iran (88.7%).20 Compared with racial groups, it is similar to African blacks (94%)14 but with a marked differences from those of Caucasians (85%), including Europeans and their descents,16 and Asians (99%).7 This suggests that the expected frequency of Rh isoimmunization would be lower in Kurds and neighboring countries than that encountered in Europeans and white Americans. Results of these study samples (53,234) out of total population of Kurds in Iraq (5,500,000) have a similar trend to the means of the world’s total studied population (2,261,025,244).28 This study and the cumulative information from different literatures indicate a multiethnic origin of the population of a country and reflect the relics of the historical movements of different racial groups in a region and in the world during disasters and wars with the ultimate changes in the history of human civilization.
From this study, we can conclude that this is the largest and most reliable data of ABO and Rh (D) phenotype frequencies in Kurds. It is close to the mean of the world’s population, with similar trending to Iranians, the neighboring Arabs, and most Europeans. The frequency of ABO and Rh phenotypes in Kurds appears to be intermediate between eastern (Asian) and western (Caucasian) data.
Acknowledgments
We thank all the staff of Hawler Teaching Hospital laboratory and Ma’moon Al-Dabbagh Health Centre Laboratory, Erbil, Kurdistan Region, Iraq and in particular, Mr Sa’ady Khalid Kadir for his cooperation and laboratory work.
Footnotes
Disclosure
The author reports no conflicts of interest in this work.
References
- 1.Watkins WM. The ABO blood group system: historical background. Transfus Med. 2001;11:243–265. doi: 10.1046/j.1365-3148.2001.00321.x. [DOI] [PubMed] [Google Scholar]
- 2.Honig CL, Bore JR. Transfusion associated fatalities: a review of bureau of biologics reports 1976–1978. Transfusion. 1980;20(6):653–661. doi: 10.1046/j.1537-2995.1980.20681057154.x. [DOI] [PubMed] [Google Scholar]
- 3.Hartmann G. Group Antigens in Human Organs. Copenhagen: Ejnar; Munksgaard; 1941. [Google Scholar]
- 4.International Society of Blood Transfusion (ISBT) Table of blood group systems. Oct, 2008. http://ibgrl.blood.co.uk/isbt
- 5.Yazer M, Olsson M, Palcic M. The cis-AB blood group phenotype: fundamental lessons in glycobiology. Transfus Med Rev. 2006;20(3):207–217. doi: 10.1016/j.tmrv.2006.03.002. [DOI] [PubMed] [Google Scholar]
- 6.Mourant AE, Kopec AC, Damaniewssta-Sobczak K. Distribution of Human blood groups and other polymorphism. 2nd ed. Oxford University Press; 1976. Northern and central Europe; pp. 62–69. [Google Scholar]
- 7.Reid ME, Lomas-Frances C. The Blood Group Antigen Facts Book. SanDiego: Academics Press; 1997. [Google Scholar]
- 8.Kolmakova GN, Kononova LL. The prevalence of ABO blood groups among persons of native nationality in Buryatia. Sud Med Ekspert. 1999;42:15–16. [PubMed] [Google Scholar]
- 9.Potts WTW. History and blood groups in the British isles. In: Sawyer PH, editor. English Medieval Settlement. New York: St. Martin’s Press; 1979. [Google Scholar]
- 10.Yamamoto F. Molecular genetics of ABO. Vox Sang. 2000;78(Suppl 2):91–103. [PubMed] [Google Scholar]
- 11.Jaff MS, O’Briain DS. Excess of blood group B in primary myelofibrosis. Vox Sang. 1987;52(3):250–253. doi: 10.1111/j.1423-0410.1987.tb03038.x. [DOI] [PubMed] [Google Scholar]
- 12.Matsushita S, Imamura T, Mizuta T, Hanada M. Acquired B antigen and polyagglutination in a patient with gastric cancer. Jpn J Surg. 1983;13(6):540–542. doi: 10.1007/BF02469500. [DOI] [PubMed] [Google Scholar]
- 13.Kremer HI, Koopmans M, de Heer E, Bruijn J, Bajema Change in blood group in systemic lupus erythematosus. Lancet. 2007;369(9557):186–187. doi: 10.1016/S0140-6736(07)60099-3. [DOI] [PubMed] [Google Scholar]
- 14.Enosolease ME, Bazuaye GN. Distribution of ABO and Rh-D blood groups in the Benin area of Niger-Delta: implication for regional blood transfusion. Asian J Trans Sci. 2008;2(1):3–5. doi: 10.4103/0973-6247.39502. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Al-Himaidi AR, Umar M. ABO blood group distribution among Saudi citizens related to their regional and original tribal location. Kuwait J Sc Eng. 2002;29(11):75–81. [Google Scholar]
- 16.Mollison PL, Engelfriet CP, Contreras M. Blood Transfusion in Clinical Medicine. 10th ed. Oxford: Blackwell Science; 1997. [Google Scholar]
- 17.Oluwadare I, Shonekan S. ABO and Rhesus ‘D’ blood type distribution in students admitted into Moshood Abiola Polytechnic, Abeokuta, Nigeria in 2006. Afr J of Biotechnol. 2008;7(11):1641–1643. [Google Scholar]
- 18.Al-Arrayed S, Shome DK, Hafadh N, et al. ABO blood group and Rhd phenotypes in Bahrain: results of screening school children and blood donors. Bahrain Medical Bulletin. 2001;23(3):112–115. [Google Scholar]
- 19.Al-Khafaji SD, Al-Rubeai MAF. The frequencies of the ABO and Rh(D) blood groups in the Kurdish population of Iraq. Ann Hum Biol. 1976;3(2):189–191. doi: 10.1080/03014467600001311. [DOI] [PubMed] [Google Scholar]
- 20.Boskabady MH, Shademan A, Ghamami G, Mazloom R. Distribution of blood groups among population of the city of Mashhad (North East of Iran) Pak J Med Sci Q. 2005;21(2):194–198. [Google Scholar]
- 21.Al-Bustan S, El-Zawahri M, Al-Azmi D, Al-Bashir AA. Allele frequencies and molecular genotyping of the ABO blood group system in a Kuwaiti population. Int J Hematol. 2002;75(2):147–153. doi: 10.1007/BF02982019. [DOI] [PubMed] [Google Scholar]
- 22.Sarhan MA, Saleh KA, Bin-Dajem SM. Distribution of ABO blood groups and rhesus factor in Southwest Saudi Arabia. Saudi Med J. 2009;30(1):116–119. [PubMed] [Google Scholar]
- 23.Hanania S, Hassawi D, Irshaid N. Allele frequency and molecular genotypes of ABO blood group system in a Jordanian population. J Med Sci. 2007;7:51–58. [Google Scholar]
- 24.Guyton AC, Hal JE. Text book of Medical Physiology. 11th ed. London: W. B. Saunders Company; 2005. [Google Scholar]
- 25.Ali N, Anwar M, Bhatti FA, Nadeem M, Nadeem A, Ali AM. Frequency of ABO and Rh blood groups in major ethnic groups and casts of Pakistan. Pak J Med Sci Q. 2005;21(1):26–29. [Google Scholar]
- 26.Kaya H, Gündodu M, Akarsu E, Kiki I, Tekin B. The distribution of blood groups in Erzurum. Med J Atatürk Univ. 1999;31:20–22. [Google Scholar]
- 27.Sakharov RS, Nofal’Kh K. The frequency of ABO blood groups and the expression of group antigens and isohemagglutinins in Syrian Arabs. Sud Med Ekspert. 1996;39(2):34–36. [PubMed] [Google Scholar]
- 28.BloodBook.Com. Racial and ethnic distribution of ABO blood types. 2003–2008. Available from: www.aboblood.com