File Name: antibody detection and identification .zip
The development of alloantibodies can significantly complicate transfusion therapy and results in difficulties in cross-matching of blood. Most literature on alloimmunization is limited to multitransfused individuals, with very few studies on the general hospital patients. This study was aimed at assessing the frequency and type of unexpected red cell antibodies in the general patient population at a multispecialty tertiary care centre in New Delhi, India.
The results of 49, antibody screening tests carried out on patients, from January to December were analyzed. The clinical and transfusion records were reviewed. The data were compiled and statistically analysed. A total of 49, 29,; Antibody screening was positive in patients 0. The overall alloimmunization rate was 0. Antibodies against the Rh system were the most frequent Since clinically significant antibodies are frequently detected in our patient population, antibody screening and if required, identification is the need of the hour.
Since antibodies against the common Rh and Kell blood group antigens are the most frequent, provision of Rh and Kell matched red cells may be of protective value. Provision of safe blood for transfusion does not only imply thorough testing for infectious markers, but also protection from haemolytic transfusion reactions resulting from alloimmunization against red cell antigens. Ever-increasing efforts at improving blood safety have led to incorporation of regular screening protocols for detection of unexpected immune antibodies at the various transfusion centres across the globe.
The ultimate goal is to determine the exact specificity of the antibody and to provide blood that lacks the corresponding antigen to the patient 1. Alloimmunization occurs when a foreign antigen introduced in an immuno-competent host evokes an immune response. This commonly occurs following transfusion of blood or in pregnancy, when red cells that bear antigens absent from the individual's own blood enter the circulation 2. The most important unexpected red blood cell alloantibodies in daily transfusion practice, in terms of frequency of occurrence, are directed towards the Rh D, C, E, c and e and Kell K antigens, followed by other blood group antigens of the Duffy, Kidd, MNS and other minor blood group systems 3.
These antibodies can cause acute and delayed haemolytic transfusion reactions as well as haemolytic disease of foetus and newborn 3 , 4. Most literature on alloimmunization is limited to multitransfused individuals 3 , 5 , 6 , 7 , 8 , with a few studies on the general hospital patients 9 , 10 , 11 , 12 , This study was carried out to assess the frequency and type of unexpected red cell antibodies in the general patient population at a multispecialty tertiary care centre in New Delhi, India.
To determine the frequency of unexpected red cell antibodies, the results of 49, antibody screening tests carried out at the Department of Transfusion Medicine, Indraprastha Apollo hospitals, New Delhi, India over a period of four years from January to December were analysed.
Antibody screening was performed on the fully automated Immunohaematology analyzer Galileo: Immucor Inc. The screening cell panels covered most antigens against which clinically significant antibodies are formed, with homozygous expression of the most important ones. In case of a positive antibody screen, further testing was performed to precisely characterize the unexpected antibody ies and to determine their specificities in case of alloantibodies.
Antibody identification was performed using different cell panels from Immucor Inc. Adsorption and elution techniques were applied whereever applicable, especially in cases of autoantibodies to look for any underlying alloantibodies.
An attempt to determine the thermal amplitudes of the autoantibodies was made by testing at various temperatures to assess their clinical significance.
Statistical analysis: Descriptive analysis and Pearson's correlation were performed for continuous variables while t test was used for non continuous variables. Table I. A total of 49, patient samples were screened for the presence of unexpected antibodies. This included 29, In patients 0. A single alloantibody was identified in patients, while 54 patients had developed more than one alloantibodies. Among the alloimmunized cases, had received one or more transfusions of blood and blood components in the past.
Of the alloimmunized women, 75 had a history including one or more pregnancies. Antibodies against the Rh system were the most frequent of alloantibodies, The exact specificity of the antibodies could not be determined in the serum of six patients. One of these cases was reported as antibody against a high incidence antigen, since most of the panel cells were reacting with it. The others were either antibodies against a low incidence antigen or an antigen not typed in the cell panel.
The frequency and specificities of the various alloantibodies identified are provided in Table II. Age of the immunized patients ranged from 1 to 91 yr with a mean age of No correlation was observed between the age of the patient and rate of alloimmunization or the number of antibodies identified.
An increase in the number of transfusions significantly raised the level of alloantibodies developed in a patient 0. Red cell alloimmunization results from the genetic disparity between red blood cell antigens of donor and recipient or from mother and foetus 2. The information available on alloimmunization especially in India is limited to select patient populations like multitransfused 6 , or pregnant women 14 and very limited data are available for general patients.
Various observational studies in general patients have estimated the presence of alloantibodies against red cell antigens between 0. The rate of alloimmunization in our general patient population was 0. The reasons for this could be that our study population comprised general hospital patients and not the high risk groups like the multitransfused. Also the antibody detection method used at our centre is specific for IgG antibodies. Various studies have used different methods for antibody screening and identification that may also detect IgM antibodies, indicating detection of a significant proportion of antibodies which are not clinically significant yet detected.
Rh and Kell antibodies have been reported to be the most common clinically significant alloantibodies 3 , 4. In our study anti E was identified as the most common antibody followed by anti D. In five patients serum samples showed reaction with occasional cells in the panel and the specificity of the antibody could not be ascertained.
These could either represent antibodies against low incidence antigens or antigens not typed in the cell panels that was used. Most commercial cell panels currently in use in India, including the one used in this study are prepared in the West, with their own donors; thus, genetic and demographic differences in between these donors and Indian patients are inevitable. A higher rate of alloimmunization was observed in females than in males.
A similar observation was made by Hoeltge et al 15 as they found higher percentage of immunized females than males. Higher rates of alloimmunization in females may be attributed to antigenic exposure during pregnancy in addition to transfusions which is the only source of exposure in men. Earlier transfusion and the number of transfusions have been identified as a significant determinant of alloimmunization 2 , 16 , 17 , although several studies have not been confirmed this association 18 , In our study the number of transfusions and pregnancies was a significant factor affecting alloimmunization rates.
The development of alloantibodies can significantly complicate transfusion therapy and result in difficulties in cross-matching of blood. Clinically significant antibodies are capable of causing mild or severe adverse events following transfusion, such as haemolytic transfusion reactions or haemolytic disease of the foetus and newborn Thus, knowledge of such alloantibodies is essential not only in the multitransfused patients but in all hospital patients who require or may require transfusion.
This not only helps in selecting appropriate RBC products for transfusion but also avoids unnecessary delays in provision of blood in case of emergencies or surgical complications.
As is evident from our results and existing literature 3 , 4 the most common alloantibodies found were against the common Rh and Kell antigens D, C, c, E, e, K , comprising nearly 71 per cent of the total alloantibodies identified.
These findings emphasize the role of extended antigen typing for recipients as well as donors, and the importance of being able to provide Rh and Kell matched blood. Besides, Rh and Kell typing of blood donors makes provision of blood for patients who have developed antibodies against these antigens easier and less time consuming. In our study, an antibody was found in the serum sample of five patients reacting with a few cells in the panel. The specificity of the antibody could not be determined and it probably represented an antibody against certain low incidence antigens or an antigen not typed in the cell panel.
This indicates towards a need to study and understand frequencies of a broader spectrum of antigens in the Indian population, besides the ones currently typed in the commercial cell panels, to determine which additional antibodies may need identification. In many centres in India, the current practice for providing compatible blood to patients in cases of alloimmunization is still reliant upon random cross-matching of available units in the inventory.
Since clinically significant antibodies are frequently detected in our patient population and cross-matching is not fully effective as a procedure of ensuring absence of the antigen to which the patient is immunized, 12 this practice is neither safe nor cost-effective. Antibody screening and if required identification, combined with phenotyping donors to provide a supply of antigen-negative blood is necessary for safe transfusion. National Center for Biotechnology Information , U.
Indian J Med Res. Author information Article notes Copyright and License information Disclaimer. Reprint requests : Dr R. Received Jun This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3. This article has been cited by other articles in PMC. Methods: The results of 49, antibody screening tests carried out on patients, from January to December were analyzed.
Results: A total of 49, 29,; Keywords: Alloimmunization, autoantibodies, general patient population, multitransfused, unexpected red cell antibodies. Table I Relationship between various factors and alloimmunization status. Open in a separate window. Results A total of 49, patient samples were screened for the presence of unexpected antibodies. Table II Frequency and specificities of the alloantibodies identified. Discussion Red cell alloimmunization results from the genetic disparity between red blood cell antigens of donor and recipient or from mother and foetus 2.
Table III Studies on alloimmunization in general hospital patients. Table IV Studies on alloimmunization in multitransfused patients. References 1. Chow EYD. The impact of the type and screen test policy on hospital transfusion practice. Hong Kong Med J. Schonewille H. Leiden: University Press; Red blood cell alloantibodies after transfusion.
Alloimmunization and erythrocyte autoimmunization in transfusion-dependent thalassemia patients of predominantly Asian descent.
not used for routine antibody detection, but very useful in antibody identification. 6 additional reactivity by indirect antiglobulin test. D. C. E c e Lea Leb. P1.
Do you find detective work exciting? Do you want to improve those skills? Our Antibody Detection and Identification course will guide you through the processes that will help you to expose the antibody that is the culprit. Antibodies must be identified so that appropriate blood products are selected for transfusion and the risk of adverse reaction is minimized.
Antibody detection and identification are performed by testing patient serum or plasma with reagent red cells. Agglutination or hemolysis indicates sensitization of the reagent red cells by an unexpected antibody in the patient's serum. The reagent red cells come with an antigram or antigen profile sheet. The antigram shows the phenotype of each reagent cell used. Antibody detection is performed using an antibody screening test. An antibody screen consists of 2 or 3 group O reagent red cells with known antigen phenotypes.
The aim of the blood transfusion service should be to provide effective blood and blood components, which are as safe as possible and adequate to meet patient's need.
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