title: Alloimmunization and autoimmunization in transfusion dependent thalassemia major patients: Study on 319 patients.
abstract: BACKGROUND
  The development of anti-red blood cell antibodies (both allo-and autoantibodies) remains a major problem in thalassemia major patients. We studied the frequency of red blood cell (RBC) alloimmunization and autoimmunization among thalassemia patients who received regular transfusions at our center and analyzed the factors, which may be responsible for development of these antibodies.
  
  
  METHODS
  The study was carried out on 319 multiply transfused patients with β-thalassemia major registered with thalassemia clinic at our institute. Clinical and transfusion records of all the patients were examined for age of patients, age at initiation of transfusion therapy, total number of blood units transfused, transfusion interval, status of splenectomy or other interventions. Alloantibody screening and identification was done using three cell and 11 cell panel (Diapanel, Bio-rad, Switzerland) respectively. To detect autoantibodies, autocontrol was carried out using polyspecific coombs (IgG + C3d) gel cards.
  
  
  RESULTS
  Eighteen patients out of total 319 patients (5.64%) developed alloantibodies and 90 (28.2%) developed autoantibodies. Nine out of 18 patients with alloantibodies also had autoantibodies. Age at first transfusion was significantly higher in alloimmunized than non-immunized patients (P = 0.042). Out of 23 alloantibodies, 52.17% belonged to Rh blood group system (Anti-E = 17%, Anti D = 13%, Anti-C = 13%, Anti-C(w) = 9%), 35% belonged to Kell blood group system, 9% of Kidd and 4% of Xg blood group system.
  
  
  CONCLUSIONS
  Alloimmunization was detected in 5.64% of multitransfused thalassemia patients. Rh and Kell blood group system antibodies accounted for more than 80% of alloantibodies. This study re-emphasizes the need for RBC antigen typing before first transfusion and issue of antigen matched blood (at least for Rh and Kell antigen). Early institution of transfusion therapy after diagnosis is another means of decreasing alloimmunization.
authors.affiliation: Department of Transfusion Medicine, PGIMER, Chandigarh, India.
authors.forename: Hari Krishan
authors.initials: HK
authors.lastname: Dhawan
authors.affiliation: Department of Pathology, Shaheed Hasan Khan Mewati, Government Medical College, Nalhar (Mewat), Haryana, India.
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumawat
authors.affiliation: Department of Transfusion Medicine, PGIMER, Chandigarh, India.
authors.forename: Neelam
authors.initials: N
authors.lastname: Marwaha
authors.affiliation: Department of Transfusion Medicine, PGIMER, Chandigarh, India.
authors.forename: Ratti Ram
authors.initials: RR
authors.lastname: Sharma
authors.affiliation: Department of Transfusion Medicine, PGIMER, Chandigarh, India.
authors.forename: Suchet
authors.initials: S
authors.lastname: Sachdev
authors.affiliation: Department of Pediatrics, PGIMER, Chandigarh, India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Bansal
authors.affiliation: Department of Pediatrics, PGIMER, Chandigarh, India.
authors.forename: Ram Kumar
authors.initials: RK
authors.lastname: Marwaha
authors.affiliation: Department of Transfusion Medicine, RML Hospital, New Delhi, India.
authors.forename: Satyam
authors.initials: S
authors.lastname: Arora
keywords: Alloimmunization; autoimmunization; thalassemia major; transfusion