ABSTRACT
BACKGROUND: Since the introduction of anti-Rh immunoglobulin prophylaxis, the incidence of hemolytic disease of the newborn (HDN) due to anti-D has remarkably decreased while the number of HDN due to ABO antibodies or minor blood group antibodies remains same. In Caucasians, anti-c, anti-E and anti-K are antibodies most frequently implicated in HDN. But in Koreans, antigenic frequency of Rh or Kell blood group is very different from Caucasians, so it is expected that the frequency of antibodies causing HDN would also be very different. Because there has been no representative data on minor blood group antibodies causing HDN in Korea, we analyzed 79 antibodies associated with HDN. METHODS: From January 1989 to July 1998, we determined the antibody specificity causing HDN in 79 cases. The nature and in vitro characteristics of the antibodies were analyzed. RESULTS: Among 79 cases, ABO antibodies were responsible in 20 cases, and anti-D was responsible in 7 cases. In minor blood group incompatibility, anti-E+c (21 cases) and anti-E (18 cases) antibodies were the antibodies most commonly involved. In ABO incompatibility, Direct Coombs' test (DAT) on baby RBC was positive only in 65% (13/20 cases). In 13 cases, ABO antibodies were detected only in the eluate of baby RBC. In non-ABO incompatibility, 96.6% (57/59 cases) showed positive DAT. In cases associated with anti-E+c and anti-E, Rh subtypes of 20 mothers were all CCDee except one, and Rh subtypes of 12 babies were all CcDEe except one. CONCLUSION: In ABO-HDN, negative DAT was frequently found and the test on baby RBC eluate was an essential part for diagnosis. Among non-ABO incompatibility, Rh incompatibilities, including RhD, were responsible in 94.9% (56/59 cases). Among HDN due to minor blood group antibodies, in contrast to previous reports, we found that anti-E+c was the most common antibody involved in HDN.