Collaborative study of irregular erythrocyte antibodies in Japan: results from the Japanese study group of allo-immunity and antigen diversity in Asian populations.

As a national study, we evaluated the frequencies of irregular erythrocyte antibodies (Abs) by gender and history of transfusion or pregnancy. In total, data from 248,785 patients were analyzed, from whom 4222 irregular erythrocyte Abs were detected in 3554 cases (1.43%). Abs frequencies in these 4222 cases were as follows: anti-E, 26%; anti-Le(a), 26%; anti-P(1), 11%; anti-M, 6%; anti-E+c, 4%; anti-Fy(b), 4%; anti-Di(a), 3%; anti-Le(b), 3%; and anti-D, 2%. In pregnancy, anti-D (5%), anti-Jr(a) (3%) and anti-E+c (6%) Abs were, with statistical significance, more frequent. Among transfused patients, anti-E (38%), anti-E+c (8%), anti-Jk(a) (4%), anti-e+C (2%) and anti-E+Jk(a) (1%) Abs were, with statistical significance, more frequent.