Asian Journal of Transfusion Science
Home About Journal Editorial Board Search Current Issue Ahead of print Back Issues Instructions Subscribe Login  Users: 1860 Print this page  Email this page Small font sizeDefault font sizeIncrease font size 

Previous Article  Table of Contents  Next Article  
Ahead of print publication
Red blood cell alloimmunization among transfusion-dependent thalassemia major patients in northeastern Iran

1 Department of Childhealth, Birjand University of Medical Sciences, Birjand, Iran
2 Department of Pediatrics, Birjand University of Medical Sciences, Birjand, Iran
3 Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran

Click here for correspondence address and email

Date of Submission28-Jul-2021
Date of Acceptance29-May-2022
Date of Web Publication12-Dec-2022


BACKGROUND: Thalassemia is one of the most common congenital hemoglobinopathies globally. Regular red blood cell (RBC) transfusion is of paramount importance in the treatment of thalassemia patients. However, this practice increases the risk of alloimmunization. This study was performed to determine the prevalence of RBC antibodies among multiple-transfused thalassemic patients in southern Khorasan, the eastern side of Iran.
METHODS: For the purpose of screening unexpected antibodies, blood samples of 68 β-thalassemia major patients were investigated. After determining positive cases through screening phase, the process of antibody identification was carried out using reagent cells.
RESULTS: The overall rate of alloimmunization was 2.9%, and the most frequent clinically important alloantibodies were anti-Kell and anti-Rh systems. Anti-K was detected in one of the patients. Furthermore, the simultaneous occurrence of anti-E and anti-C was seen in another study subject.
CONCLUSION: A number of factors might have contributed to the low alloimmunization rate detected in this study, including the homogeneity of the population in South Khorasan, well-matched donors for those patients, first transfusion at an early age, and the use of leukodepleted blood.

Keywords: Alloantibody screening, alloimmunization, β-thalassemia major

How to cite this URL:
Mobasheri L, Chahkandi T, Talebpour A, Sarab GA. Red blood cell alloimmunization among transfusion-dependent thalassemia major patients in northeastern Iran. Asian J Transfus Sci [Epub ahead of print] [cited 2023 Jan 28]. Available from:

   Introduction Top

The thalassemia syndromes are the most common heterogeneous group of inherited single-gene blood disorders characterized by partial or complete deficiency of α-globin (alpha-thalassemia) or β-globin (beta-thalassemia) chain of hemoglobin (Hb) production, resulting in anemia ranging from severe to clinically asymptomatic individuals.[1],[2] Thalassemia affects approximately 4.4 of every 10,000 live births throughout the world.[3] There are no significant gender differences in the prevalence of this disease.[4] Thalassemia has a high frequency in a broad belt, extending from the Mediterranean basin through the Middle East (Iran), India, and Southeast Asia and South China.[5],[6] Iran is located in the middle of thalassemia belt with more than 18,000 affected individuals.[7] Beta-thalassemia major, also known as “Cooley's anemia,” usually reveals its manifestations in the 1st year of life in 95% of the patients, and it has been evaluated that there are 80 million carriers with β-thalassemia universally.[8] Life-long blood transfusion therapy for the maintenance of Hb around 9–11.5 g/dl appears to be the primary medication for these patients following the extensive usage of hematopoietic stem cell transplantation for the treatment of the disease.[8],[9] The adverse effects of repetitive allogeneic blood transfusion, despite being lifesaving process, include iron overload, increased rate of transfusion-transmissible infections, and alloimmunization to red cell antigens.[10],[11] Alloimmunization occurs due to the genetic inconsistency between the recipient and donor red cell antigens and the recipient's immune system response (alloantibody) against incompatible foreign red blood cell (RBC) antigens.[12] Reports have confirmed that the variable rate of alloimmunization in multi-transfused thalassemia patients ranges from 4% to 50% with a lower incidence in more homogeneous populations.[13] Alloimmunization is usually against “low frequency” antigens (minor antigens) that are not considered clinically significant in sporadic transfusions, but they may be of considerable importance in multiply transfused patients.[14] As blood is routinely matched with main blood group antigens, i.e., ABO and Rh D antigen, there is a high probability for alloimmunization against clinically important other blood group antigens such as Kell (K), Kidd (Jk), Duffy (Fy), and Rh C and E.[9] Development of anti-RBC is associated with hemolysis and complication in transfusion therapy. Difficulty in obtaining compatible blood units, cross-matching of blood, and a higher rate of transfusion are serious complications in blood management of patients with thalassemia. Identification of antigens and transfusion of fully compatible blood may prevent alloimmunization.[15]

The aim of this study is to determine the frequency of alloimmunization and identify the most common alloantibodies associated with red cell antigens in southern Khorasan thalassemic patients. Thus, the current study aims to help formulate transfusion strategies for all the multi-transfused thalassemic patients in the southern part of Khorasan, east of Iran.

   Methods Top


This cross-sectional descriptive study was carried out in Birjand province (southern Khorasan, Iran) over a period of 2 years from July 2018 to May 2020. The study protocol was approved by Ethics Committee at Birjand University of Medical Sciences. A total of 68 living patients diagnosed with β-thalassemia major inclined to participate in the study were registered at Birjand Blood Transfusion Organization, which reached 100% voluntary blood donations for the thalassemia patients in South Khorasan, Iran.

Thalassemic patients were confirmed through physical examinations, complete blood count tests, and special Hb tests conducted by a hematologist. These patients received leukocyte-reduced packed RBCs about once a month. The demographic information of the patients including age and sex and information on transfusion history such as the first time of transfusion and the interval between consecutive transfusions, levels of ferritin, spleen status, viral tests (anti-HIV, anti-HTLV1, anti-HCV, anti-HBC, hepatitis B surface antibody, and hepatitis B surface antigen) were collected from the patient records at the Medical Center of Special Diseases of South Khorasan, Iran.

Laboratory process

First, venous blood samples were obtained from each subject (10 ml). Next, 2 ml of each sample was transferred into ethylenediaminetetraacetic acid tubes to determine the blood types' phenotypes, and the remaining was moved to serum-separating tubes. Screening of unexpected antibodies was carried out for all of the patients according to the standard instructions of the Iranian Blood Transfusion Organization (IBTO) with three O-cell vials (R1R1, R2R2, and rr) sensitized to clinically important antigens of all known blood groups, including Rh (D, C, E, c, e, f, and Cw), Kell (K, k, Kpa, Kpb, Jsa, and Jsb), Kidd (Jka and Jkb), Duffy (Fya and Fyb), P (P1), Lewis (Lea and Leb), MNS (M, N, S, and s), Lutheran (Lua and Lub), and Xga. The screening was performed in different reaction conditions such as room temperature, 37°C/albumin, and 37°C/antihuman globulin (AHG). After determining positive cases through screening phase, the process of antibody identification was carried out using 11 reagent cells (panels) provided by IBTO in 3 phases including room temperature, 37°C/albumin, and 37°C/AHG.

Statistical analysis

All statistical calculations were performed using the SPSS statistical software (version 16.0; SPSS Inc., Chicago, IL, USA). Qualitative data were statistically expressed in the form of frequency and percentages. Numerical data were statistically represented in terms of range, mean, and standard deviation (±). Pearson Chi-square or Fisher's exact test was used to test the association between gender and age group.

   Results Top

A total of 68 β-thalassemia major patients were examined at blood transfusion center in South Khorasan province. There were 35 (51.5%) males and 33 (48.5%) females (M: F ratio of 1.06:1) whose ages ranged from 1 to 28 years, with a mean age of 13.67 ± 5.4. Qualitative and numerical clinical information of thalassemic patients is given in [Table 1] and [Table 2], respectively. The median level of ferritin in patients was 3334 ng/ml, ranging from 236 to 11465. In this study, 25% of the patients were splenectomized, and the mean age of the first transfusion was 10.34 ± 8.6 months with a range of 2–48 months. Patients had been receiving regular compatible packed leukodepleted red cells every 2–4 weeks. Two subjects were found positive for RBC alloantibodies (2.9%): one of them with one type of alloantibody (anti-Kell) and the other with two types of alloantibodies (anti-C and anti-E) [Table 3]. There was no statistically significant correlation between the existence of alloantibodies and the age or gender of the patients. The most common ABO group was O (39.7%), followed by A (30.9%) and B (23.5%). Nearly 85% of the patients were RhD positive. Out of the 68 patients, 1 case (2.9%) was positive for HTLV1, and 2 cases (23.1%) were reactive for anti-HBC.
Table 1: Qualitative clinical data of thalassemic patients

Click here to view
Table 2: Numerical clinical data of thalassemic patients

Click here to view
Table 3: Profile of alloimmunized thalassemia patients

Click here to view

   Discussion Top

Chronic RBC transfusion among thalassemia patients might induce alloantibody formation against minor blood group systems such as Kidd, Kell, Duffy, and Rh systems which may complicate transfusion therapy in these patients.[7] We found alloantibodies in 2 out of 68 patients, indicating an overall frequency of alloantibody development of 2.9%.

Lower rates of alloimmunization may be expected when there is an antigenic homogeneity between recipients and donors in a population. In this way, ethnicity can play a significant role in this matter.[16],[17],[18] Since the vast majority of donors in this study are of the same ethnicity, this theory was somewhat corroborated by the current research. Previous studies on homogenous populations in Greece, Italy, and Malaysia showed lower rates of alloimmunization, 5%, 10%, and 1.13%, respectively.[15],[19],[20],[21] A study in Saudi Arabia reported alloimmunization rate among thalassemia patients who received multiethnic blood was 22.06%.[22] In another study, the rate of alloimmunization in Asian patients who had received transfusion predominantly from American donors was 22% and mainly noted that c, S, K, and Fyb antigens were all potentially hemolytic antibodies.[23] It has been indicated that heterogeneity of the population in Taiwan caused the prevalence of 37% of alloimmunization in this population.[24] Furthermore, a higher rate of approximately 20% was noted in two Greek studies and one study in Egypt with a rate of 42.5% when blood matched only for ABO and Rh-D antigens was used.[2],[25],[26]

Apart from the antigenic homogeneity between the recipient and the donor as a main factor affecting the alloimmunization process, there are also other factors that are worth considering. The role of immune system is quite well recognized in this regard.[27] The splenectomy and asplenia cause long-term residues of foreign antigens in the blood circulation that may further enhance the immune response to the foreign antigens which are not effectively filtered.[28] Thus, the low rate of alloimmunization in our study may lie in the low rate of our splenectomized patients. The immune response may also be affected by the patient's age at the start of transfusion and the number of blood transfusions that a patient receives. Blood transfusion at an early age (up to 3–4 years old) may lead to tolerance and protection against alloimmunization in thalassemia patients. In the current study, the mean age of the first blood transfusion was 10.34 months. However, the relation between the number of blood units transfused and the antibody formation is almost unknown in thalassemia, but it is an important factor in increased alloimmunization in the patients with sickle cell disease, who receive multiple transfusions.[25],[27] Besides, another reason for the low rate of the alloimmunization in the current study, subjects may be attributed to a number of studies that have shown leukodepleted RBC units, or leukoreduction filters may decrease the alloimmunization because of the possible alleviation of the patient's sensitization process by the Human leukocyte antigens (HLA) system.[6],[29],[30] Last but not least, investigations have shown that the “better match” policy can reduce the prevalence of patients with clinically significant red cell alloantibodies.[21] Hence, the low rate of the alloimmunization may be ascribed to some extent to the fact that the thalassemic patients in South Khorasan Province are carefully monitored with appropriate antibody screening. Some studies have reported that most alloantibodies were against Rh (especially Rh E and Rh C, alone, or simultaneously) and Kell systems.[22],[31],[32] Therefore, the evaluation of packed cells for Rh (anti-C and E) and Kell (anti-K) systems from the beginning of transfusion can be effective in reducing the frequency of alloantibody synthesis. Phenotype matching based on the patient phenotype in the patients who have not yet produced any alloantibodies could reduce the cost of consequent alloimmunization complexities or even the rate of consequent deaths.

   Conclusion Top

Based on our findings, anti-Rh and anti-Kell were the most prevalent alloantibodies in this study. Despite multiple transfusions, there was a favorable condition in terms of alloimmunization in this study. However, this does not necessarily mean that in the subsequent continuous exposures to antigens caused by blood transfusions, this statement will continue. The results of this study emphasize the importance of red cell antigen typing and antigen matching from the beginning of transfusion, especially for the Rh and Kell antigens. Thus, a safe and sufficient blood supply is important for enhancing the quality of life and survival of these thalassemic patients.


The authors would like to thank the Vice-Chancellor of Research and Technology in Birjand University of Medical Sciences and Birjand Blood Transfusion Organization for the good support in this study. The grant number of this study was Ir.bums.REC.1398.162.

Financial support and sponsorship

This study was financially supported by the Birjand University of Medical Sciences, Birjand Blood Transfusion Organization.

Conflicts of interest

There are no conflicts of interest.

   References Top

el-Danasoury AS, Eissa DG, Abdo RM, Elalfy MS. Red blood cell alloimmunization in transfusion-dependent Egyptian patients with thalassemia in a limited donor exposure program. Transfusion 2012;52:43-7.  Back to cited text no. 1
Obaid JM, Abo El-Nazar SY, Ghanem AM, El-Hadidi AS, Mersal BH. Red blood cells alloimmunization and autoimmunization among transfusion-dependent beta-thalassemia patients in Alexandria province, Egypt. Transfus Apher Sci 2015;53:52-7.  Back to cited text no. 2
Smith Y. Thalassemia Genetic Prevalence; 2018. Available from: [Last updated on 2018 Aug 23].  Back to cited text no. 3
Kulkarni M. Clinical Methods in Paediatrics. New Delhi, India: Jaypee Brothers Medical Publishers; 2005.  Back to cited text no. 4
Li CK. New trend in the epidemiology of thalassaemia. Best Pract Res Clin Obstet Gynaecol 2017;39:16-26.  Back to cited text no. 5
Matteocci A, Pierelli L. Red blood cell alloimmunization in sickle cell disease and in thalassaemia: Current status, future perspectives and potential role of molecular typing. Vox Sang 2014;106:197-208.  Back to cited text no. 6
Davoudi-Kiakalayeh A, Mohammadi R, Pourfathollah AA, Siery Z, Davoudi-Kiakalayeh S. Alloimmunization in thalassemia patients: New insight for healthcare. Int J Prev Med 2017;8:101.  Back to cited text no. 7
[PUBMED]  [Full text]  
Putzulu R, Piccirillo N, Orlando N, Massini G, Maresca M, Scavone F, et al. The role of molecular typing and perfect match transfusion in sickle cell disease and thalassaemia: An innovative transfusion strategy. Transfus Apher Sci 2017;56:234-7.  Back to cited text no. 8
Jain R, Choudhury N, Chudgar U, Harimoorthy V, Desai P, Perkins J, et al. Detection and identification of red cell alloantibodies in multiply transfused thalassemia major patients: A prospective study. Indian J Hematol Blood Transfus 2014;30:291-6.  Back to cited text no. 9
Elhence P, Solanki A, Verma A. Red blood cell antibodies in thalassemia patients in northern India: Risk factors and literature review. Indian J Hematol Blood Transfus 2014;30:301-8.  Back to cited text no. 10
Jansuwan S, Tangvarasittichai O, Tangvarasittichai S. Alloimmunization to red cells and the association of alloantibodies formation with splenectomy among transfusion-dependent β-thalassemia major/HbE patients. Indian J Clin Biochem 2015;30:198-203.  Back to cited text no. 11
Datta SS, Mukherjee S, Talukder B, Bhattacharya P, Mukherjee K. Frequency of red cell alloimmunization and autoimmunization in thalassemia patients: A report from eastern India. Adv Hematol 2015;2015:610931.  Back to cited text no. 12
Azarkeivan A, Ahmadi MH, Zolfaghari S, Shaiegan M, Ferdowsi S, Rezaei N, et al. RBC alloimmunization and double alloantibodies in thalassemic patients. Hematology 2015;20:223-7.  Back to cited text no. 13
Belsito A, Costa D, Fiorito C, De Iorio G, Casamassimi A, Perrotta S, et al. Erythrocyte genotyping for transfusion-dependent patients at the Azienda Universitaria Policlinico of Naples. Transfus Apher Sci 2015;52:72-7.  Back to cited text no. 14
Al-Joudi F, Ali AB, Ramli MB, Ahmed S, Ismail M. Prevalence and specificities of red cell alloantibodies among blood recipients in the Malaysian state of Kelantan. Asian J Transfus Sci 2011;5:42-5.  Back to cited text no. 15
[PUBMED]  [Full text]  
Hmida S, Mojaat N, Maamar M, Bejaoui M, Mediouni M, Boukef K. Red cell alloantibodies in patients with haemoglobinopathies. Nouv Rev Fr Hematol 1994;36:363-6.  Back to cited text no. 16
Ho HK, Ha SY, Lam CK, Chan GC, Lee TL, Chiang AK, et al. Alloimmunization in Hong Kong southern Chinese transfusion-dependent thalassemia patients. Blood 2001;97:3999-4000.  Back to cited text no. 17
Yazdanbakhsh K, Kang S, Tamasauskas D, Sung D, Scaradavou A. Complement receptor 1 inhibitors for prevention of immune-mediated red cell destruction: Potential use in transfusion therapy. Blood 2003;101:5046-52.  Back to cited text no. 18
Economidou J, Constantoulakis M, Augoustaki O, Adinolfi M. Frequency of antibodies to various antigenic determinants in polytransfused patients with homozygous thalassaemia in Greece. Vox Sang 1971;20:252-8.  Back to cited text no. 19
Coles SM, Klein HG, Holland PV. Alloimmunization in two multitransfused patient populations. Transfusion 1981;21:462-6.  Back to cited text no. 20
Sirchia G, Zanella A, Parravicini A, Morelati F, Rebulla P, Masera G. Red cell alloantibodies in thalassemia major. Results of an Italian cooperative study. Transfusion 1985;25:110-2.  Back to cited text no. 21
Gader AG, Al Ghumlas AK, Al-Momen AK. Transfusion medicine in a developing country – Alloantibodies to red blood cells in multi-transfused patients in Saudi Arabia. Transfus Apher Sci 2008;39:199-204.  Back to cited text no. 22
Singer ST, Wu V, Mignacca R, Kuypers FA, Morel P, Vichinsky EP. Alloimmunization and erythrocyte autoimmunization in transfusion-dependent thalassemia patients of predominantly Asian descent. Blood 2000;96:3369-73.  Back to cited text no. 23
Wang LY, Liang DC, Liu HC, Chang FC, Wang CL, Chan YS, et al. Alloimmunization among patients with transfusion-dependent thalassemia in Taiwan. Transfus Med 2006;16:200-3.  Back to cited text no. 24
Michail-Merianou V, Pamphili-Panousopoulou L, Piperi-Lowes L, Pelegrinis E, Karaklis A. Alloimmunization to red cell antigens in thalassemia: Comparative study of usual versus better-match transfusion programmes. Vox Sang 1987;52:95-8.  Back to cited text no. 25
Spanos T, Karageorga M, Ladis V, Peristeri J, Hatziliami A, Kattamis C. Red cell alloantibodies in patients with thalassemia. Vox Sang 1990;58:50-5.  Back to cited text no. 26
Ameen R, Al-Shemmari S, Al-Humood S, Chowdhury RI, Al-Eyaadi O, Al-Bashir A. RBC alloimmunization and autoimmunization among transfusion-dependent Arab thalassemia patients. Transfusion 2003;43:1604-10.  Back to cited text no. 27
Bhatti FA, Salamat N, Nadeem A, Shabbir N. Red cell immunization in beta thalassaemia major. J Coll Physicians Surg Pak 2004;14:657-60.  Back to cited text no. 28
Schonewille H, Brand A. Alloimmunization to red blood cell antigens after universal leucodepletion. A regional multicentre retrospective study. Br J Haematol 2005;129:151-6.  Back to cited text no. 29
Buetens O, Shirey RS, Goble-Lee M, Houp J, Zachary A, King KE, et al. Prevalence of HLA antibodies in transfused patients with and without red cell antibodies. Transfusion 2006;46:754-6.  Back to cited text no. 30
Al-Riyami AZ, Al-Muqbali A, Al-Sudiri S, Murthi Panchatcharam S, Zacharia M, Al-Mahrooqi S, et al. Risks of red blood cell alloimmunization in transfusion-dependent β-thalassemia in Oman: A 25-year experience of a university tertiary care reference center and a literature review. Transfusion 2018;58:871-8.  Back to cited text no. 31
Sadeghian MH, Keramati MR, Badiei Z, Ravarian M, Ayatollahi H, Rafatpanah H, et al. Alloimmunization among transfusion-dependent thalassemia patients. Asian J Transfus Sci 2009;3:95-8.  Back to cited text no. 32
[PUBMED]  [Full text]  

Correspondence Address:
Gholamreza Anani Sarab,
Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ajts.ajts_107_21


  [Table 1], [Table 2], [Table 3]


[PREVo] Next Article

     Search Pubmed for
    -  Mobasheri L
    -  Chahkandi T
    -  Talebpour A
    -  Sarab GA
   Article in PDF

    Article Tables

 Article Access Statistics
    PDF Downloaded7    

Recommend this journal

Association Contact us | Sitemap | Advertise | What's New | Copyright and Disclaimer | Privacy Notice

2006 - Asian Journal of Transfusion Science | Published by Wolters Kluwer - Medknow
Online since 10th November, 2006