Phenotyping and Genotyping of HNA: Prevalence, Risk of Alloimmunization, and HNA Incompatibilities in Indians.

Background: Antibodies to human neutrophil alloantigens (HNA) are involved in the pathophysiology of several clinical conditions including transfusion-related acute lung injury (TRALI), alloimmune and autoimmune neutropenia, and febrile nonhemolytic transfusion reactions leading to neutropenia. The cognate antigens are polymorphic structures expressed on several glycoproteins on the neutrophils, i.e.

Red cell antigen phenotypes in blood donors & thalassaemia patients for creation of red cell antigen-matched inventory.

Background & Objectives: Patients with thalasssaemia are at a risk of alloimmunization and the presence of RBC alloantibodies further complicates transfusion therapy. Matching for the critical antigens of Rh, Kell, Kidd and Duffy blood group systems has been shown to minimize alloimmunization. The aim of the present study was to create a database of extensively typed donors for clinically significant and common blood group antigens of Rh, Kidd, Kell and Duffy systems for transfusion therapy of multitransfused thalassaemic patients.

Detection of a rare subgroup of A phenotype while resolving ABO discrepancy.

Weaker subgroups of ABO blood group system give rise to discrepancies between forward and reverse grouping and cause diagnostic difficulties in routine blood banking. Weaker subgroups of A blood group that have been reported so far include A3, Aend, Ax, Am, Ay, and Ael. We report a case of a 54-year-old patient whose red cells showed a discrepancy between cell and serum grouping on initial testing.

Molecular genotyping of clinically important blood group antigens in patients with thalassaemia.

Background & Objectives: In multitransfused thalassaemic patients, haemagglutination fails to phenotype the patient's blood group antigens due to the presence of donor-derived erythrocytes. DNA-based methods can overcome the limitations of haemagglutination and can be used to determine the correct antigen profile of these patients. This will facilitate the procurement of antigen-matched blood for transfusion to multitransfused patients.

RHD-Positive Alleles among D- C/E+ Individuals from India.

Background: Molecular bases of blood group systems, including Rh blood group, have been poorly studied in the Indian population so far, while specificities of Europeans, East Asians and Africans have been well known for years. In order to gain insights into the molecular bases of this population, we sought to characterize the allele in D- Indian donors expressing C and/or E antigen(s).

Methods: gene was analyzed in 171 serologically D-, C/E+ samples by standard molecular methods such as quantitative, multiplex PCR of short fluorescent fragments (QMPSF) and direct sequencing when necessary.

Molecular genotyping of Indian blood group system antigens in Indian blood donors.

Background: Haemagglutination has been the gold standard for defining the blood group status. However, these tests depend upon the availability of specific and reliable antisera. Potent antisera for extended phenotyping are very costly, weakly reacting or available in limited stocks and unavailable for some blood group systems like Indian, Dombrock, Coltan, Diego etc.

Heterogeneity of O blood group in India: Peeping through the window of molecular biology.

Background: Molecular genotyping of ABO blood group system has identified more than 60 "O" group alleles based on the single-nucleotide polymorphisms present in the ABO gene. Heterogeneity of O group alleles has been observed in various countries from South America, Europe, Middle East, and Asia. India is a vast country with more than 1300 million population which is divided into various ethnic and tribal groups.

Molecular basis of weak D expression in the Indian population and report of a novel, predominant variant RHD allele.

Background: The Rh blood group system is the most polymorphic system and is implicated in hemolytic transfusion reaction and hemolytic disease of the fetus and newborn. Molecular genetics of the RH genes have been extensively studied in Caucasians, Africans, and East Asians and the variant alleles giving rise to weak and partial D phenotypes have been reported. However, limited genetic studies have been carried out in the large Indian population, even though the variability of Rh expression has been documented.

Evolution of technology for molecular genotyping in blood group systems.

The molecular basis of the blood group antigens was identified first in the 1980s and 1990s. Since then the importance of molecular biology in transfusion medicine has been described extensively by several investigators. Molecular genotyping of blood group antigens is one of the important aspects and is successfully making its way into transfusion medicine.

First report of Rh individuals in the Indian population and characterization of the underlying molecular mechanisms.

Background: Rh phenotype is an extremely rare condition characterized by no expression of Rh antigens at the surface of red blood cells. Although rare, genetic bases of this phenotype are well known and include mutations within either the RH (RHD and RHCE) genes or the RHAG gene. So far Rh has been reported in individuals of Caucasian, African, and Asian origin.

Partial matching of blood group antigens to reduce alloimmunization in Western India.

Red blood cell alloimmunization occurs due to the genetic disparity of red cell antigens between donor and recipient. In the present study, we report a spectrum of red cell alloantibodies characterized in patients with different clinical conditions in a reference center in India. Majority of the antibodies identified were against the blood group antigens c, D, E, M, N, S, s and Jka.