Difference of Allo-Immunity to Erythrocytes in Asian Countries: Cooperative Study of Allo-Immunity to Antigen Diversity in Asian Population.
Authors: Watanabe Hiroko , Takeshita Akihiro , Kim Dae Won , Kwon So Yong , Han Kyou Sup , Suh Jang Soo , Natalie Chan Pui Ha , Nadarajan Veera Sekaran , Permpikul Parichart , Marican Nuranissa Bte Yacob , Uchikawa Makoto , Kino Shuichi , Ohto Hitoshi 
Published: October 2019

Abstract
Abstract 2112
Poster Board II-89
(Purpose) Asian populations have a wide variety of genetics and circumstances. Therefore, immune responses to allo-antigens may differ from those that are common among American and European populations. However, we have little information from Asian populations, and collaborative international study is required to improve the success of blood transfusions and transplantations. Therefore, we tried to analyze allo-antibodies (Abs) to erythrocyte antigens in patients from Asian countries. (Method) Forty-eight institutes, including those in Japan (29), Korea (15), Hong Kong (1), Singapore (1), Malaysia (1) and Thailand (1), participated to this cooperative study of allo-antibodies to erythrocyte antigens in Asian populations. We investigated the number of blood grouping tests, cross matching tests, and erythrocyte irregular Ab analyses as well as information of institutes including total number of bed, operations and transfusions performed. We also investigated methods adopted for screening and detecting irregular Abs to erythrocyte antigens. Furthermore, we studied the frequencies of irregular Abs to erythrocytes (D, C ,c, E, e, f, Ce, P1, M, N, S, s, Mia, Lea, Leb, Jka, Jkb, Jk3, Fya, Fyb,K, k, Kpa, Kpb, Jsa, Jsb, Dia, Dib, Lua, Lub, Xga and H), and compared them among Asian countries. The total number of independent cases included more than 866,000 patients. If a case was analyzed multiple times, we counted it as one case. Multiple antibodies detected in a patient were separately summarized. (Results) Ab screening methods adopted in these institutes included gel columns, beads columns, traditional tubes or some combination of these three. There was no difference in the methods including the erythrocyte panel adopted. Among the serum of 8,880 patients (male /female: 1 /1.55) 10,069 antibodies were detected. The numbers of these patients registered in each country are as follows; 4,222 in Japan, 2,423 in Korea, 975 in Malaysia, 622 in Thailand, 612 in Hong Kong and 26 in Singapore. On average, anti-E Ab was detected in 25.7% (min-max country, 14.3-32.2%) of patients, anti-Lea 20.9 % (3.2-30.4), anti-Mia 7.3% (0-49.4), anti-P1 6.6 % (0-10.6), anti-M 5.6 % (0-7.0), ant-c+E 4.9 % (1.6-8.5), anti-Leb 4.3 % (0-7.6), anti-D 4.0 % (0-16.2), anti-Fyb 2.2 % (0-3.7), anti-Dia 1.9 % (0-3.3), anti-Jka 1.7 % (0.8-7.7), anti-C+e 1.5 % (0-3.3), anti-Lea+Leb 1.4 % (0-5.8), anti-S 1.1 % (0-1.9), anti-c 1.1 % (0-2.3) and other Abs 9.9 %. Anti-D Ab was frequently observed in patients from Korea and Malaysia compared to Thailand, Hong Kong and Japan. Anti-Lea Ab was frequently observed in patients from Malaysia, Japan, Singapore and Korea. Anti-Dia Ab was observed in patients from Japan and Korea. Anti-Mia Ab was frequently observed in patients from Thailand and Hong Kong, followed by Malaysia and Singapore, and rarely from Japan and Korea. (Conclusion) This is the first international collaborative study on allo-immunity to erythrocyte antigens in Asian populations. There are some important differences among Asian countries with regard to the presence of anti-D, -Lea, -Dia and -Mia Abs. Further, the proportions of detected Abs, (such as anti-K, -D and -MiaAbs) differ from those reported in previous studies of patients from US and European counties (Winters et al, Hoeltge et al, Walker et al, etc). These new data will contribute to the advancement in successful blood transfusion in Asia and the world. Furthermore, the study will strengthen the network of international collaboration in future.

Disclosures:
No relevant conflicts of interest to declare.