The prevalence of GP Mur and anti-"Mia" in a tertiary hospital in Peninsula Malaysia

The Mi III phenotype of the Miltenberger subsystem (or GP Mur) is relatively common in Southeast Asia especially along the south-east coast lines of China and Taiwan. The term anti-"Mia" describes antibodies that react with the Mi III phenotype. Since the Peninsula Malaysian population is a multiethnic one with a significant proportion of Chinese, a study was conducted into the prevalence of anti-"Mia" in patients from its 3 major ethnic groups--Chinese, Malays and Indians, as well as the GP Mur phenotype in blood donors (healthy individuals). Blood samples from 33,716 patients (general and antenatal) were screened for anti-"Mia" from January 1999 to December 2000. The investigation for the GP Mur phenotype representing the corresponding sensitizing antigen complex was carried out in 655 blood donors. Serum anti-"Mia" antibody was found to be the third most commonly occurring antibody detected in our patients and was found in all the ethnic groups. The antibody was detected in 0.2% of 33,716 antenatal and general patients with a prevalence in Chinese of 0.3%, Malay 0.2% and Indian 0.2%. The detection of these antibodies in the ethnic groups other than the Chinese is a noteworthy finding as such information is not well documented. The GP Mur red cell phenotype was detected in 15/306 (4.9%) of Chinese blood donors, a lower prevalence than in Chinese populations in other countries in the region. More significant was its detection in the Malays (2.8%) and the Indians (3.0%). Because of the many reports of clinical problems associated with the "Mia" antibody including the causation of fetal hydrops and haemolytic transfusion reactions, it is warranted that the GP Mur red cells be included in screening panels for group and screen procedures in countries with a significant Asian population.