title: Clinical significance of antibody specificities to M, N and Lewis blood group system.
abstract: BACKGROUND
  The clinically significant antibodies are those active at 37°C and/or by the indirect antiglobulin test. Most of the published literature refers to antibodies of Lewis blood group system to be insignificant, whereas antibodies to M and N blood groups are associated with variable clinical significance.
  
  
  OBJECTIVE
  The aim of this study is to find the frequency and clinical significance of antibodies to M, N and Lewis blood group systems.
  
  
  METHODS
  The study was carried out retrospectively from January 2009 to December 2012.
  
  
  METHODS
  Antibody screening was performed by solid phase red cell adherence (SPRCA) technique using four cell screening panel on a fully automated platform GALILEO (Immucor Inc. USA). In case of a positive antibody screen, antibody identification was performed using SPRCA (GALILEO, Immucor Inc. USA).
  
  
  RESULTS
  A total of 49,077 red cell antibody screens were performed and a total of 427 identifications of red cell antibodies were carried out. A total of 304 specific antibodies were detected: 8.22% of antibodies were of anti-M specificity and 2.96% were of anti-N specificity. Majority (84%) of anti-M and 77.78% of anti-N were of Immunoglobulin G (IgG) class reacting at 37°C. 1.31% of the antibodies were directed against Lewis system antigens of which 0.65% were anti-Lea and 0.65% were anti-Leb. Half of the Lewis system antibodies, i.e., 1 each of anti-Lea and anti-Leb were of IgG class.
  
  
  CONCLUSIONS
  Our study highlights the importance of detecting the thermal amplitude of antibodies with variable clinical significance especially if both IgG and IgM types of antibodies are associated with it so as to establish their clinical significance.
authors.affiliation: Department of Transfusion Medicine, Molecular Biology and Transplant Immunology, Indraprastha Apollo Hospitals, New Delhi, India.
authors.forename: Raj Nath
authors.initials: RN
authors.lastname: Makroo
authors.affiliation: Department of Transfusion Medicine, Molecular Biology and Transplant Immunology, Indraprastha Apollo Hospitals, New Delhi, India.
authors.forename: Bhavna
authors.initials: B
authors.lastname: Arora
authors.affiliation: Department of Transfusion Medicine, Molecular Biology and Transplant Immunology, Indraprastha Apollo Hospitals, New Delhi, India.
authors.forename: Aakanksha
authors.initials: A
authors.lastname: Bhatia
authors.affiliation: Department of Transfusion Medicine, Molecular Biology and Transplant Immunology, Indraprastha Apollo Hospitals, New Delhi, India.
authors.forename: Mohit
authors.initials: M
authors.lastname: Chowdhry
authors.affiliation: Department of Transfusion Medicine, Molecular Biology and Transplant Immunology, Indraprastha Apollo Hospitals, New Delhi, India.
authors.forename: Rosamma Nakamatathil
authors.initials: RN
authors.lastname: Luka
keywords: Anti-M; Lewis; anti-N; clinical significance