S-C Lo1, J-S Chang, S W-S Lin, D-T Lin. 1. Department of Laboratory Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10018, Taiwan.
Abstract
BACKGROUND AND OBJECTIVES: The red blood cell Mi III phenotype is prevalent in Asia, and its corresponding alloantibody, anti-Mi(a), has been reported to cause haemolytic transfusion reactions and haemolytic disease of the newborn. However, a complete picture of the immunological characteristics of anti-Mi(a) is still lacking. We therefore conducted a systematic study to evaluate the potential clinical significance of this antibody. MATERIALS AND METHODS: From April 1999 to March 2000, we identified 60 sera containing anti-Mi(a) among pretransfusion samples at a teaching hospital in Taiwan. These antibodies were tested for immunoglobulin class, thermal range and activity in a monocyte monolayer assay. RESULTS: Thirty-four (57%) of the antibodies were immunoglobulin M (IgM), and 15 retained their activity at 37 degrees C. Of those that were immunoglobulin G (IgG), 96% were of subclasses IgG1 and/or IgG3. Monocyte monolayer assay studies showed that 69% (18/26) of the IgG anti-Mi(a) sera were reactive. CONCLUSIONS: Our study justifies the implementation of anti-Mi(a) screening in Taiwan.
BACKGROUND AND OBJECTIVES: The red blood cell Mi III phenotype is prevalent in Asia, and its corresponding alloantibody, anti-Mi(a), has been reported to cause haemolytic transfusion reactions and haemolytic disease of the newborn. However, a complete picture of the immunological characteristics of anti-Mi(a) is still lacking. We therefore conducted a systematic study to evaluate the potential clinical significance of this antibody. MATERIALS AND METHODS: From April 1999 to March 2000, we identified 60 sera containing anti-Mi(a) among pretransfusion samples at a teaching hospital in Taiwan. These antibodies were tested for immunoglobulin class, thermal range and activity in a monocyte monolayer assay. RESULTS: Thirty-four (57%) of the antibodies were immunoglobulin M (IgM), and 15 retained their activity at 37 degrees C. Of those that were immunoglobulin G (IgG), 96% were of subclasses IgG1 and/or IgG3. Monocyte monolayer assay studies showed that 69% (18/26) of the IgG anti-Mi(a) sera were reactive. CONCLUSIONS: Our study justifies the implementation of anti-Mi(a) screening in Taiwan.