Identification of Rh alloantibody in Thalassaemia Patients

Summary: Thalassaemiais a congenital hemolytic disorder caused by partial or complete deficiency of α or β globin chain synthesis. The disease is treated by lifelong red cell transfusion. So they are at high risk of developing allo-antibodies, resulting difficult to obtain compatible blood, results in, haemolysis & occasionally life threatening events. Objectives: To find out the frequency of Rhesus alloantibodies among the thalassaemic patients. Methods: This cross sectional study was done in the department of transfusion medicine in Bangabandhu Sheikh Mujib Medical University from 01-07-2010 to 03-07-2011. Sample size was 100 and the data was collected by face to face interview. Purposive sampling method was applied using inclusion & exclusion criteria. Statically analysis of the result was obtained by using window based computer software devised with Statistical Packages for Social Sciences (SPSS-15) (SPSS Inc, Chicago, IL, USA). Result: In the present study all respondent were Rh D-positive. Out of 100 respondents 2 (2.0%) had positive direct Coomb’sand 6 (6.0%) had positive indirect Coomd’s test. Out of 6 respondent with Rhesus all-antibody, 4 (66.7%) had anti E antibody, 1(16.7%) had anti c antibody and 1 (16.7%) had non specific antibody. Conclusion: In this study among the 100 respondents of thalassaemic patients who receive regular blood transfusion 6 (6.0%) had developed rhesus allo-antibody among with the most common was Anti E antibody 4 (66.7%). Such information may enable understanding and prevention of this serious and common complication.

globin chain synthesis. 2,4The most severe forms of βthalassemia major present within the first year of life with severe anaemia and failure to thrive.The disease is treated by lifelong red cell transfusion.Regular transfusions are essential for patients with thalassemia to maintain growth and development during childhood and to sustain good quality of life during adulthood. 4The mainstay of therapy fo severe beta-thalassaemia syndromes is periodic blood transfusions. 5Thalassemic patients receiving.Multiple transfusions are at high risk of developing alloantibodies. 3,4,6hey are generally given to correct the anemia, prevent ineffective erythropoiesis and improve growth and development. 5 is estimated by the WHO, the World Bank, and other international agencies that there is a massive increase in the number of patients with different forms of thalassemia in many emerging countries and it is imperative to establish more surveys of the frequency of the disease and set up centers for its control and management. 2 Despite there being numerous foreign epitopes on essentially all transfusions of nonautologous RBCs, transfusion is not a highly immunogenic stimulus.Even in response to multiple transfusions, alloimmunization to alloantigens on transfused RBCs has an overall frequency of approximately 2-6% 6 .The development of erythrocyte alloantibodies complicates transfusion therapy in patients with thalassemia. 4,7The Rh and Kell system alloantibodies are most frequent.However, in a majority of the alloimmunized patients, usually one alloantibody is detected.Patients with alloantibodies against one blood group system are prone to the development of alloantibodies to other blood group systems due to genetic and acquired patient-related factors. 6loimmunization to erythrocyte antigens is a frequent complication in & transfusion-dependent thalassemia. 4This type of sensitization results in difficulty obtaining compatible blood, transfusion reactions, haemolysis and occasionally life-threatening events.Thalassemia is a relatively common condition and it is well known that the development of erythrocyte alloantibodies complicates transfusion therapy for this disorder. 4Antibodies to some blood group antigens frequently causehemolysis (clinically significant, e.g.ABO, Rh, Kell, Kidd, Duffy, MNSs, Lewis), whereas others cause no deleterious effect (clinically insignificant, e.g.Anti-LW, Ge, Xg, Sc, Chido, Rogers, Bg).The prevalence of alloantibodies in thalassemics in India is 4-7%.The Rh and Kell system alloantibodies are most frequent. 5,6In a study found significant levels of red cell alloantibodies were present in 11 patients (25%), and 8 patients (18%) had red cell autoantibodies. 8e development of erythrocyte alloantibodies complicates transfusion therapy inpatients with thalassemia.However, no data are available on the frequency of erythrocyte alloimmunization in patients with transfusion-dependent thalassemia in Bangladesh.In this study, we will investigate the frequency of alloantibodies among patients receiving regular red cell transfusions for thalassemia.

Methodology:
This is a cross sectional studywas conducted in the Department of Transfusion Medicine, Bangabandhu Sheikh Mujib Medical University from 1 st July 2010 to 30 th June 2011.100 thalassaemia patients were seen and purposive sampling method was applied including both sex and rhesus D antigen positive with age group 2-50 years.Data was collected by face to face interview and stastical analyses of the results were obtained by using window based computersoftware devised with Statistical Packages for Social Sciences(SPSS-15)(SPSS Inc, Chicago, IL, USA).Out the 100 respondents 49 were male and 51 were female, Male female ratio was 1:1.04.

Blood transfusion
Frequency Percent

Discussion:
Thalassemia is one of the most common genetic disorders.
It is estimated that 300,000 infants are born with major hemoglobinopathies worldwide in each year of whom 60,000 to 70,000 are beta thalassemia major cases especially inthe Mediterranean area, Middle East, Far East, and East Asia. 9Major advances have occurred in the treatment and prevention of thalassemia major. 10The survival of patients increased significantly with the improvement of conventional therapy and some of them reach mature age and are exposed to higher risk of new complications. 11Almost all patients with thalassaemia major require blood transfusion within the first two to three years of life to prevent severe anaemia and its physical consequences. 12Life-long transfusion remains the main treatment for severe thalassemia.The development of anti-RBC antibodies, (alloantibodies and or autoantibodies) can significantly complicate transfusion therapy. 13It is well known that the development of erythrocyte alloantibodies complicates transfusion therapy. 4Alloimmunization and autoimmunization are common, serious complications in Asian thalassemia patients, who are affected by donor-recipient RBC antigen mismatch and immunological factors. 4,13Alloimmunization to erythrocyte antigens is a frequent complication in transfusion-dependent thalassemia.This type of sensitization results in difficulty obtaining compatible blood, transfusion reactions, haemolysis and occasionally life-threatening events. 4The RBC antigenic difference between the blood donor and therecipient; 2, The recipient's immune status; 3. The immunomodulatory effect/ of the allogeneic blood transfusions on the recipient's immune system are thethree factors for alloimmunization.13 Mean ± SD age of the respondents was 16.75 ± 14.15 with a range of 2 to 50 years.52 (52.0%) of the respondents were in the age group of 2 to 10 years followed by the age group of 11 to 20 years (16.0%).Other age group 21 to 30 years, 31 to 40 years and 41 to 50 years were 14 (14.0%), 9 (9.0%) and 9(9.0%) respectively 10 showed that in 1973, a survey wasdone of the ages of 243 living patients with thalassemia major followed at 12 centers in the United States and Canada.22.0% percent were younger than 5 years and 2.1% were older than 25 years (mean 11.4±6.7 [SD] years).In1985, there were 303 patients at the same centers; 11% were younger than 5years and 7.9% were older than 25 years (mean 14.2±7.3years.In a study 12 from the 12 reference hospitals for two decades show increasing mean ages of patients in 1973, 11.4 ± 6.7 years; in 1985, 14.2±7.3years; and in 1993, 16.H9.2years. Inngladesh a study by 21 of 152 with thalassaemic patients found the mean age of 6.8±3.6 years.In a study 20 found the mean±SD age of patients was 13.0 ± 6.1 years and ranged from 2 to 26 years.Mean ± SD age of the respondents in the studies by 12,20 found similarity with the preserlt study.But the study by 21 were found dissimilarity with the present study. In this present study out of 100 respondents 49 were male and 51 were female.Male to female ratio was 1:1.04. 13in a study of 64 patients found 37 were females and 27 were males.Male to female ratio was 1:1.37. 20In a study of 121 patients 66 (54.5 %) were females and 55 (45.5%) were males.Male to female ratio of the present study comparable with the studies of 13,20 .
A low rate of alloimmunization may be expected when there is homogeneity of RBC antigens between the blood providers and recipients. 13In this study 2 (2.0%) had positive direct Coombs' test and 6 (6.0%) hadindirect Coombs' test.In a study 13 showed that the incidenceof red cell alloimmunization among Asian patients in the United States was 20.8%, which was attributed majnly to differences in the distribution of red cell antigens between Caucasian donors and Asian recipients. 13ta on presumed homogenous populations studied by 14 in Greece and 15 in Italy showed an overall low rate (5% to 10%) of alloimmunization. 13Studies have reported a rate of red cell alloimnmnization ranging from 5 to 20% 16,17,18,19,20 E; two cases of anti c and one case of anti-4 Mia', anti-D and anti-S.In their study three patients had two alloantibodies.In the present study amongthe respondents with rhesus alloantibody anti E antibody were most frequent which can be compared with the study by. 13,4nclusion: In this study among the 100 respondents of thalasaemic patients who receive regular blood transfusion, 2(2.0%) had positive direct Coombs' test and 6(6.0%) had positive indirect Coombs' test.Anti E antibody is the most common rhesus alloantibody found in this study.
Due to the short study period, more sample number and further investigation could not be achieved.With the growing knowledge base of the immune effects of current blood transfusion and limited data on the immune status of thalassemia patients, a large study addressing the complex interaction of these factors is needed.Such information may enable understanding and prevention of this serious and common complication.

Recommendation:
All thalasaemic patients should have done phenotype & Genotype prophylactically before planning of transfusion.
Blood should be cross-matched by ICT method.If antibody is identified then corresponding antigen negative blood should be transfused.
Large scale study is recommended. complication.

Table I
Distribution of age of the respondentsTable-II shows the distribution of sex of the respondents.

Table -
III shows the distribution of frequency of blood transfusion.In 70.0% of respondents frequency of blood transfusion was monthly followed by irregular frequency (20.0%).Frequency of blood transfusion of rest 10.0% was weekly.Table-IV shows the distribution of adverse effect during blood transfusion.Out of 100 respondents adverse effect present in 40.0% and 60.0% had no adverse effect.

Table
VII shows the distribution of alloantibody by Coombs' test among the respondents.Out of 100 respondents 2 (2.0%) had positive direct Coombs' test and 6 (6.0%) had indirect Coombs' test.

Table 8
shows the distribution of Rhesus alloantibody among the respondents.Out of 6 respondents with rhesus alloantibody, 4 (66.7%) had anti E antibody, 1 (16.7%) had 1 (16.7%) had non specific antibody.No respondents were presented with anti C antibody and antic antibody.