|Year : 2022 | Volume
| Issue : 1 | Page : 47-50
Antibody screening and identification in voluntary blood donors – Need of the hour
Rakesh Kumar Luhar, Ripal J Shah, V Harimoorthy
Prathama Blood Centre, Ahmedabad, Gujarat, India
|Date of Submission||04-Jan-2022|
|Date of Decision||13-Feb-2022|
|Date of Acceptance||07-Apr-2022|
|Date of Web Publication||29-Apr-2022|
Dr. Rakesh Kumar Luhar
Prathama Blood Centre, Ahmedabad, Gujarat
Source of Support: None, Conflict of Interest: None
Background and Objectives: Although unexpected antibody screening is mandatory according to the Food and Drug Administration and National Blood Policy, the prevalence of irregular red cell antibody and its specificities are not much reported in the donor population of western India. The objective of this study is to find the prevalence of unexpected antibodies in healthy blood donor population of western India. Methods: This is a retrospective study conducted in one of the largest stand-alone blood centers in western India. Data were retrieved from the Integrated Blood Bank Management System (powered by the blood center located in Ahmedabad) software. The data were analyzed for a period of 24 months, from March 1, 2019, to March 31, 2021. Unexpected antibody screening of all voluntary healthy blood donors was performed with fully automated blood grouping equipment Immucor NEO and Diagast EVO using commercial Capture-R Ready Indicator Red Cells (Immucor, USA) and Hemascreen Pool (Diagast, France). Further antibody identification was performed with 11 cell panels. Results: A total of 53,724 volunteer blood donors donated at our blood center during the study period comprised 51,185 (95.27%) male donors and 2539 (4.72%) female donors. A total of 25 (0.046%) donors showed the presence of unexpected antibodies. Most frequent alloantibodies were anti-M (n = 4, 16%) and multiple antibody (n = 4, 16%). Conclusion: Implementation of unexpected antibody screening in all the healthy blood donors routinely and identification of antibodies in antibody screen-positive donors helped us to understand the prevalence of antibodies in our region and its importance in providing compatible blood components which are devoid of irregular antibodies and to avoid delayed transfusion reactions.
Keywords: Antibody identification, antibody screening, unexpected antibody, voluntary blood donor
|How to cite this article:|
Luhar RK, Shah RJ, Harimoorthy V. Antibody screening and identification in voluntary blood donors – Need of the hour. Glob J Transfus Med 2022;7:47-50
|How to cite this URL:|
Luhar RK, Shah RJ, Harimoorthy V. Antibody screening and identification in voluntary blood donors – Need of the hour. Glob J Transfus Med [serial online] 2022 [cited 2022 May 20];7:47-50. Available from: https://www.gjtmonline.com/text.asp?2022/7/1/47/344323
| Introduction|| |
Red cell antibodies, anti-A and anti-B, are the naturally occurring antibodies that are commonly detected in the human plasma. All other antibodies are not naturally present but are developed and detected only after exposure to the corresponding antigens. These antibodies are called “irregular red cell antibodies.” There are two types of irregular red cell antibodies: alloantibodies and autoantibodies. Alloantibody is produced against the antigen that is lacking on individual own red cells, whereas autoantibody is produced against own red cells. Such irregular alloantibodies/autoantibodies can be sometimes encountered in healthy blood donors who are either transfused previously or in multiparous females. These irregular antibodies mainly include antibodies against antigens from Rh, MNSs, Duffy, and Kidd blood group systems. These antibodies are very important clinically because they may cause critical transfusion reactions such as acute or delayed hemolytic transfusion reaction or neonate hemolytic syndrome.
As per the Food, Drug, and Cosmetic Act (FDCA), irregular allo/autoantibodies refer to antibodies that are reactive at 37°C or detected in the antihuman globulin phase of testing. The reactivity of these antibodies is highly varied and unpredictable. These antibodies can be encountered in healthy blood donors who are either transfused previously or in multiparous females. As per the National Blood Policy, India, 2007, in addition to infectious marker screening, blood donors should be screened for unexpected antibodies to avoid any adverse transfusion reaction, especially in case of the transfusion of plasma-containing components.
There is a paucity of literature on the prevalence of irregular red cell antibodies in whole blood donor population. The reported incidence of irregular antibodies from various studies ranges from 5 to 10 in 10,000 blood donors and even higher (20%) in regularly transfused populations (sickle cell disease or thalassemia patients).
Aims and objectives
The objective of this study is to find the prevalence of unexpected antibodies in healthy blood donors in western India.
| Materials and Methods|| |
This is a retrospective study conducted at one of the largest stand-alone blood centers in western India over a 2-year duration from March 1, 2019, to March 31, 2021. Total donations from 53,724 healthy blood donors were included in the current study.
Donors who are eligible for blood donation according to the Institutional Standard Operating Procedure based on National FDCA, National AIDS Control Organization, American Association of Blood Banks, National Accreditation Board for Hospitals and Healthcare Providers, WHO, and Director General of Health Services (DGHS) guidelines were selected. Donated blood was screened for the irregular/unexpected antibody along with ABO-Rh blood group and transfusion-transmitted infection testing. Subtle donor screening was done at the time of blood donation. Informed consent was taken before each blood donation.
All universal precautions were taken while sample blood collection, processing, and testing. All the donor samples were collected from the blood donation in K2 Ethylene diamine tetra-acetic acid (EDTA) vaccuttes for blood grouping and unexpected antibody screening. Blood grouping was performed using Solid Phase Red Cell Adherence Assay (SPRCA) and Erythrocyte Magnetized (EM) technology on fully automated blood group equipment NEO and Diagast EVO using commercial Capture-R Ready Indicator Red Cells (Immucor, INC.3130 Gateway Drive Norcross, GA 30071 USA) and Hemascreen Pool reference cell (Diagast,251, Avenue Eugene Avinee BP9-59374 Loos cedex-France). Unexpected antibody screening was performed using commercial pooled “O” reference cell and using commercial Capture-R Ready Indicator Red Cells (NEO) and Hemascreen Pool (Diagast EVO) use. Any sample found positive for unexpected antibodies with pooled cells was subjected to antibody identification.
Majority of the identification was done with 11 cell panels from Diagast. Antibody presence was confirmed with the absence of corresponding antigen.
All blood donors who had donated blood at our center during the study period were included in the current study.
None were excluded from the study.
All the data were compiled and tabulated and frequencies and percentages were calculated using Microsoft Excel spreadsheet 2007 (12.0.4518.1014).
The current study was retrospective data analysis. The ethical clearance was taken from the institutional ethical committee.
| Results|| |
A total of 53,724 healthy donors donated blood at our blood center during the study period. Among these, 51,185 (95.27%) donors were male and 2539 (4.73%) were female. A total of 25 (0.046%) donors showed the presence of unexpected antibodies with commercial pooled O-cells. The overall frequency of alloantibody among blood donors is depicted in [Table 1].
Anti-M antibodies were the highest (n = 04/25, 16%) among all antibodies identified. There were some cases in which antibodies could not be determined. This was attributed to multiple reasons such as multiple antibodies and solid-phase phenomena (SPP). This undetermined antibody also constitutes the same prevalence of anti-M (n = 04/25, 16%).
Next common were anti-D and anti-E each (n = 3/25 each, 12%). Antibodies of Rh blood group system with anti-C, anti-c, and anti-Cw (1/25, 4%) each were also detected. SPP antibody (n = 3/25) was also showing 12% prevalence in the study group.
| Discussion|| |
The unexpected antibody can be detected in general healthy blood donor population. The prevalence of alloantibodies was found to be 0.046% (25/53, 724) in our donor population.
Factors influencing the immunization rate and distribution of red blood cell (RBC) alloantibody include age, gender, ethnicity, number of transfusions, autoimmune disease, immunoglobulin G (IgG) level, lymphoproliferative disease, solid malignancy, and number of incompatible erythrocytes received by the individual through transfusion. Proper detection and identification of unexpected or irregular alloantibody in donors are important for smooth and safe transfusion to patients. The prevalence of such irregular red cell antibodies has been extensively studied in patients in various parts of the world and also in India, but the data regarding exclusive donor population are very limited.
Data from various other studies reported that the rate of alloimmunization among blood donors varies from 0.05% to 3.9%. In our study population, the prevalence of unexpected antibodies is 0.046%, which is almost similar to other studies from India, as depicted in [Table 2].,,,,,, The difference in various frequencies in various studies could be due to the different methodology used for antibody screening and identification and heterogeneity of the population studied. In our study, SPRCA and erythrocyte-magnetized method have a sensitivity of 97%–98%.
A study from Seattle, Washington, had reported a 0.32% incidence of irregular RBC antibodies in blood donors, and a study by Winters et al. in 2001 reported a prevalence of 1.4% (n = 257 of 18,185 donors studied) among blood donors of Olmsted County, Minnesota. This high prevalence of antibodies in these studies was attributed to higher number of females in donor population who were previously transfused or had a history of pregnancy.
In our study, irregular RBC alloantibodies in males (n = 23, 92%) and females (n = 2, 8.0%) donors were observed. When compared to number of donors donated from both the genders, the prevalence of irregular antibodies was higher in female donors (0.078%) as compared to male donors (0.045%), as depicted in [Table 3]. Our observation differs from observation from a similar study conducted by Makroo et al. (n = 63, 82.90%). Naturally occurring antibodies which may present in either male or female population without a previous history of transfusion or pregnancy, if detected during antibody screening, should be checked for clinical significance as per institutional policies.
In the present study, 28% (n = 7) of donor antibodies could be undetermined antibodies. Donors showing positive antibody screening with the presence of inconclusive antibody panel could be possibly due to low-titer antibodies in the donor serum. The other possibility could be that these antibodies are directed to antigens not present in the screening cell panel.
They are suspected when screen and panel cells are positive with reactions in the same phase and at the same strength, along with a negative auto control. Seven donors in the present study (28%) showed the presence of undetermined antibodies. The plasma units from these units were sent for fractionation purpose as per the institutional protocol, and donor notification was given.
Anti-M generally naturally occurring alloantibodies which does not react at 37°C and are not clinically significant for transfusion but can cause a problem in pretransfusion testing. These antibodies are clinically significant when reactive at 37°C where plasma and platelets shall be issued for fractionation purpose to prevent unusual transfusion reactions and packed red cells can be issued after appropriate compatible crossmatch. The frequency of M antigen globally is 75%; hence, 25% of the individuals lack M antigen, who are able to generate anti-M antibody when exposed to the antigen which could be the best possible explanation of such high frequency.
The second common antibody in our study was anti-D with a frequency of 12% (n = 3) followed by anti-E (n = 3). Approximately 80%–85% of D-negative persons makes anti-D after exposure to D-positive RBCs. Anti-E is an IgG antibody directed against the E antigen in the Rh blood group system. Anti-E is implicated in hemolytic transfusion reaction and hemolytic disease of the fetus and newborn. Patients with anti-E must receive E-negative blood.
Anti-SPP antibody was found to be 12% (n = 3). The solid-phase phenomenon antibody is a good indicator that patients will develop alloantibodies in future with a formation rate of 11% which is higher than expected normal rate of antibody development of 1%–2% per unit of RBC transfused. Therefore, these patients are at higher risk and should be monitored carefully in future to determine if RBC alloantibodies develop over time.
A study by Meade et al. used solid-phase technology at their institution, and they have experienced an increase in pan-reactive antibody screens and panels but negative when changing to manual tube method or other enhancement media. This pattern of reactivity is termed as SPP.
The Lewis blood group system is different from other blood group systems, as the antigens (Lea and Leb) are formed in the plasma and absorbed onto the red cell membrane. Although Lewis antibodies present in recipients are implicated in hemolytic transfusion reaction, there is no report highlighting its clinical significance of Lewis antibodies in donor plasma. These antibodies may be clinically relevant if the antibody causes in vitro hemolysis during serologic laboratory testing and antigen-negative blood should be selected for transfusion. In our donors, the incidence of anti-Lea was 8% (n = 2). Like the present study, Chenna et al. also reported the presence of Lewis antibodies in their study group.
The limitation of the study was incomplete immunohematology workups in cases of undetermined antibodies or inconclusive antibodies due to lack of availability of rare red cell reagents or local reference laboratories for serological or molecular confirmation.
| Conclusion|| |
This study emphasizes the need for the mandatory screening and identification of unexpected antibodies among healthy blood donors, and it helps to serve by providing safe blood components which are devoid of any irregular antibody. Irregular antibody screening in donors is not done regularly in many centers in India. Red cell antibody screening of the donors is a simple test, adds a layer of safety in transfusion, and reduces the need for minor crossmatching for plasma transfusion. In such cases, only packed RBCs should be used for transfusion. In addition, we recommend that in cases where the antibody is found in blood donors, the donor should be informed. Prevalence of RBC antibodies also helps to develop rare donor registries.
We would like to express our gratitude to Diagast and Immucor, India, for extending their support in antibody identification. We are thankful to staff of blood center for the technical support in performing the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]