Harnessing the potential of blood donors negative for high prevalence Rh antigens: A database initiative for thalassaemia care.

With increasing life expectancy and prevalence of thalassaemia, it has led to a greater need for safe blood, yet the current supply from voluntary donors is insufficient to meet this demand. Thalassaemia recipients face a significant risk of alloimmunization because of repeated exposure to foreign red cell antigens. Study aims to determine high prevalent Rh antigen negative donors in western India donor population along with what percentage of these donors are willing to become dedicated voluntary donors for thalassaemia patients. Study also aims to examine factors influencing their willingness and challenges faced in mobilizing dedicated donors. 700 whole blood donors from western India, following screening for inclusion & exclusion criteria as per Drugs and Cosmetic Act (DCA) 2020 amendment guidelines & were sero-negative for transfusion transmitted infections were enrolled for the study. Red cell phenotyping was performed using Conventional Tube Technique (CTT) for "D", "C", "E", "c", "e" and "K" antigen using known antisera. Donors that were "C" AND/OR "e" antigen negative were contacted telephonically and were counseled and motivated for becoming voluntary blood donors. Statistical analysis assessed correlation between donation frequency, donor's occupation and education. Among 700 donors, 96.6% (n = 676) were males and 3.4% (n = 24) were females. The most predominant blood group was B > O > A > AB. Rh(D) antigen was present in 91.44% (n = 640) and absent in 8.6% (n = 60). Prevalence of other Rh antigens is as follows: "e" (99%) > "C" (85.4%) > "c" (59.1%) > "E" (18.0%). Only 1.15% had "K" antigen positive. The commonest Rh phenotype R1R1 (DCe/DCe) was expressed by 40.57% (n = 283), and the least common r″r (cE/ce), r″r″ (cE/cE) and r'r' (Ce/Ce) was found in 0.14% (n = 1), respectively. 'C' negative, 'e' negative, 'C' and 'e' antigen negative donors constituted 14.8% (n = 104) with 93.2% (n = 97) C-antigen negative, 1.92% (n = 2) e-antigen negative and 4.8% (n = 5) both "C" and "e" antigen negative donors. The commonest phenotypes among C-antigen and e-antigen negative donors were rr (50%) and RzR2 (1.94%) respectively. Likewise, the most common phenotype amongst both C- and e-antigens negative donors was R2R2 (3.84%). 61.5% of the donors agreed to enroll for voluntary blood donation following telephonic invitation, while 6.8% of them refused permanently. Approximately, 3.9% of the blood donors were willing to donate blood only when needed and 27.8% of them could not be contacted. Creating a database of voluntary donors with known phenotype, especially who lack very common antigens like "C" and "e" and are willing to become dedicated, regular voluntary donors for thalassemic patients can ensure timely administration of safe blood. One of the major challenges for this noble initiative was lack of awareness which can be circumvent effectively with proper counseling efforts.

Gupta A ，Bava D ，Kaur P ，Chatterjee AK ，Kumar A ，Nigam A ，Tripathi A ，Kumar R ... -  《-》

Rh and Kell phenotyping in voluntary blood donors: A study from a tertiary care blood center of western India.

In human beings, there are 45 blood group systems and 360 antigens currently recognized by ISBT (July 2023). The Rh blood group system has 56 antigens, out of them 5 antigens D, C, c, E, and e are clinically significant antigens. The Kell blood group system has 25 highly immunogenic antigens. Cases have been reported where IgG-type of antibodies against Rh and Kell antigens are found which are responsible for transfusion reactions and hemolytic disease of newborn. To study the prevalence of Rh-Kell phenotype in voluntary blood donors, To provide Rh and Kell antigen-matched blood products to patients to prevent alloimmunization, To make a donor directory of Rh and Kell phenotyped donors for further use. The antigen typing for Rh antigens (D, C, c, E, and e) and Kell (K) was performed on the collected ethylenediaminetetraacetic acid samples from 1014 voluntary donors. The test was performed by Erythrocyte Magnetic Technique using a microplate (DuoLys) in a fully automated immunohematology system (Diagast Qwalys Evo 3 instrument). From 1014 phenotyped donors, the most common antigen frequency was of "e" (98.6%) followed by "D"(96.2%),"C"(89.4%), "c"(54.8%), and "E"(18.6%). The frequency of the "K" antigen was (1.38%). The most common Rh phenotype from the study population was R1R1(CDe/CDe) (45%) and the rarest was r'r' (Ce/Ce) (0.1%). Knowledge of the phenotype frequency in the local population is helpful in making a donor directory, In situations where clinically significant alloantibodies are found in patient's serum, antigen-negative blood unit can be arranged using a donor directory.

Shah SD ，Bhatnagar NM ，Shah MC ，Thakkar GH ，Ahuja U ，Patel A ，Gajera D ，Kalavadiya PG ... -  《-》

Pattern of distribution of 35 red cell antigens in regular voluntary blood donors of South Gujarat, India.

Extended phenotyping is one of the important method of reducing red cell alloimmunisation. Extended phenotyping of red cells from voluntary donors have many uses in addition to its application in population genetics. As there was very little data extended phenotyping on a cohort of Indian Voluntary blood donors this project was undertaken. 200 regular voluntary blood donors having 'O' blood group were included for red cell antigen typing of Rh (D,C,E,c,e), Kell (K, k, Kpa, Kpb), Duffy (Fya, Fyb), Kidd (Jka, Jkb), Lewis(Lea, Leb), P(P1), MNS (M, N,S,s), and Lutheran (Lua, Lub), Colton (Coa, Cob), Diago (Diaa, Wra), Vw and Xga antigens using conventional antisera provided by DIAGAST. Calculations of antigen and phenotypes frequencies were expressed as percentages. Out of 200 'O' group blood donors, 96.5% were Rh D and 2.5% were K positive. Amongst Rh antigens, e was the most common (100%) followed by D, C (91.0%), c (50.5%) and E (16.5%) with DCe/DCe (R1R1, 48.0%) being the most common phenotype. In Kell blood group system, we found k antigen to be 100% and a rare phenotype Kp (a + b+) was found in 1% of the donors. For Kidd and Duffy blood group systems, Jk (a + b+) and Fy (a + b-) were the most common phenotypes (39.0% and 64.0%, respectively). In the MNS blood group system, M + N+ (67.5%) and S + s+(43.5%) were the most common phenotypes. There were antigens like Cw(3.5%), K(2.3%), Kpa(1.2%), Ina(1.0%), Vw(1.2%), Coa(4.5%), Cob(1%), Lua(1.75%), Dia+(1.2%), and Wra+(0.6%) with frequency < 5% in the donor population. Extensively antigen phenotypes group 'O' red cells showed significant variation with other population from India as well as with Caucasian and black population. Extensive phenotyping 'O' group regular blood donors of red cell antigens is very useful to prepare in-house red cell panels for identification of alloantibodies.

Shah A ，Jariwala K ，Gupte S ，Sharma P ，Mishra K ，Ghosh K ... -  《TRANSFUSION AND APHERESIS SCIENCE》

Prevalence of Principal Rh Blood Group Antigens in Blood Donors at the Blood Bank of a Tertiary Care Hospital in Southern India.

Gundrajukuppam DK ，Vijaya SB ，Rajendran A ，Sarella JD ... -  《-》

The value of transfusion of phenotyped blood units for thalassemia and sickle cell anemia patients at an academic center.

Blood transfusion is the first-line treatment for patients with thalassemia and many sickle cell patients. However, cases of unregulated blood transfusion are shown to carry a high risk of alloimmunization to red blood cells (RBCs), which can lead to a hemolytic transfusion reaction and be fatal to patients. Screening and identification of alloantibodies are, therefore, essential practice in blood transfusion services. Transfusion of phenotyped blood can minimize these risks to patients. A prospective study was carried out on 1015 donors, and a prospective and retrospective study was carried out on 208 multiple transfused patients with β-thalassemia and sickle cell anemia. Donor and patient samples were subjected to Rh & K typing, and patient samples were also subjected to screening & identification of RBC antibodies. We aimed to determine the prevalence of RBC antigens in thalassemia and sickle cell patients, as well as blood donors, at King Abdulaziz University Hospital and the frequency of alloimmunization in the selected patients. The most commonly detected Rh-phenotype in donors was R1r (32.02%), followed by R1R1 (23.25%). Only 9.16% of donors were positive for the K antigen. The prevalence of Rh and K blood group antigens was also reported: the highest detected Rh-phenotype was R1r (40.86%) followed by R1R2 (24.04%) with only (6.25%) positive patients for K antigen. The rate of alloimmunization among sickle cell anemia and thalassemia patients was 39.42% and 35.57%, respectively. The highest specificity rates of the alloantibodies were recorded for anti-E and anti-K in both patient groups. The rate of alloimmunization in transfused patients was high and particularly observed against the Rh and K antigens. This study emphasizes the clinical need for typing patient RBCs prior to transfusion so as to provide phenotyped matched blood units and minimize the risks and associated morbidities of alloimmunization. Keeping a database of phenotyped blood donors is essential for the clinically effective and safe management of transfusion patients.

Hindawi S ，Badawi M ，Elfayoumi R ，Elgemmezi T ，Al Hassani A ，Raml M ，Alamoudi S ，Gholam K ... -  《-》