Analysis of Ambiguities of HLA-DR Typing using the Dynal RELI(TM) SSO HLA-DRB Kit and Development of an 'Interpretation Program for Koreans' / 대한진단검사의학회지

BACKGROUND: HLA-DR typing kits using reverse-SSO (sequence specific oligonucleotide) method show considerable ambiguities in HLA-DRB1 generic typing. We analyzed the ambiguities of the Dynal RELI(TM) SSO HLA-DRB test (Dynal DRB test) and developed an 'Interpretation Program for Koreans'. METHODS: A total of 3,000 Koreans were typed for HLA-DRB1/B3/B4/B5 using the 36 probe Dynal DRB test and all of the cases showing ambiguities in HLA-DRB1 generic typing were subjected to confirmatory typing using the PCR-single strand conformation polymorphism (SSCP) method. On the basis of these results, an 'Interpretation Program for Koreans'was developed for the 45 probe Dynal DRB test. RESULTS: Among 3,000 Koreans tested by the 36 probe Dynal DRB test, 456 cases (15.2%) showed ambiguities. In 95% of the ambiguity cases (433/456) and 99.2% of the total cases tested (433/3,000), the'most probable type'could be expected from the DRB1 gene frequencies and DRB1-B3/B4/B5 associations in Koreans and these results were in accordance with the confirmatory typing results as well as the results given by the 'Interpretation Program for Koreans'. Similarly, the 'Most Probable'could be assigned by the program in 99.4% (348/350) of the cases tested with the 45 probe Dynal DRB test. CONCLUSIONS: Ambiguity in the Dynal DRB test was observed in >15% of the Korean samples tested. The majority (95%) of the ambiguities could be resolved on the basis of HLA-DRB1 gene frequencies and DRB1-B3/B4/B5 associations in Koreans. Furthermore, using the program developed in this study, the correct assignment of DRB1 generic types was possible without additional typing in the majority (>99%) of the cases tested.

A Case of Anti-Xga Antibody / 대한수혈학회지

Authors experienced a patient with anti-Xga antibody in the serum. To our knowledge, this is the first report of anti-Xga antibody in Korea. The patient was a 65-year-old male with chronic renal failure who had received many hemodialyses. Anti-Xga antibody has not been implicated in hemolytic disease of the newborn or hemolytic transfusion reactions, but the antibody can be misinterpreted as clinically significant antibody in crossmatching because it usually reacts only on antiglobulin testing. In this case, no transfusion reactions happened.

Development of Homemade Indicator Cells for Platelet Antibody Test by Mixed Passive Hemagglutination / 대한임상병리학회지

BACKGROUND: Platelet antibody test has been used in the diagnosis and management of immunological platelet disorders and platelet crossmatch. Mixed passive hemagglutination (MPHA) test is a cost-effective, reproducible, easy to perform and convenient method. Anti-IgG coated indicator red cells used for MPHA test have not been made in Korea and those cells have been exclusively donated by Dr. Shibata in Japan. This study was designed to produce domestic indicator cells and to determine its acceptability by comparing to the results obtained with Dr. Shibata's indicator cells. We produced homemade indicator cells by coating human RhD-positive O RBC with human IgG anti-D (check cell) and then coated with rabbit anti-human IgG. METHODS: Sixty three sera from healthy male donors, 58 sera tested positive in platelet suspension immunofluorescence test (PSIFT), and 61 sera tested negative in PSIFT were evaluated by MPHA employing both homemade and Dr. Shibata's indicator cells. RESULTS: The concordance rate between PSIFT and homemade MPHA was 74%. Test results of MPHA with homemade indicator cell showed excellent correlation with Shibata's indicator cell (P=0.002). All of 63 sera from healthy volunteer male blood donors without history of transfusion were tested negative with homemade MPHA method. Test results of MPHA employing homemade indicator cells showed excellent correlation with those of PSIFT (P=2.67x10-8). CONCLUSIONS: Homemade indicator cells we developed in this study were able to replace Dr. Shibata's indicator cells for the MPHA test.

Diagnostic significance of serum A and B glycosyltransferase assay for the classification of ABO subgroups

BACKGROUND: A and B transferase are glycosyltransferase that transfer N-acetylgalactosamine and D- galactose to H antigen, respectively and lead to the expression of A and B phenotypes in ABO blood group system. Reduced or no activities of serum A and B transferase were observed in some A and B subgroup individuals. Determining the activities of serum A and B transferase can be useful in discriminating rare A and B subgroups. MATERIALS AND METHODS: ABO typing, saliva test, adsorption elution test and serum transferase assay were performed on samples from 12 individuals showing ABO discrepancy or weakened cell typing reactions which were referred to the Seoul National University Hospital to confirm their ABO blood types. Serum transferase activity was assayed by determining the ability of serum to convert group 0 RBCs into A or B cells. RESULTS: Determination of serum ABO transferase activity was useful in the identification of Ael (3 cases), B. (2 cases), Bm (1 case), Am (1 case), Bx (1 case), 0 with weakened anti-A or anti-B (3 cases), and A without anti-B due to hypogammaglobulinemia (1 case). CONCLUSION: Determining serum A and B glycosyltransferase activity was proven to be a simple and useful tool for the classification of several ABO subgroups.(Korean J Blood Transfusion 10(1): 27-33, 1999)

Development of decision support system for antibody identification / 대한수혈학회지

BACKGROUND: Determination of antibody specificity using antigram spread sheet requires experience and knowledge on in vitro characteristics of red cell antibodies, time-consuming, and still subjective to human error. A computer-based antibody identification system was developed to overcome these disadvantages. METHODS: Decision support system program for antibody identification was designed using Visual Basic 5.0 for Dade Data-cyte Plus. This system integrates the reaction patterns of saline, 37degrees C albumin, antiglobulin, 4degrees C saline enzyme treated and user-defined phases and lists the antibodies according to the probability. 115 irregular antibodies previously confirmed by standard manual method reanalyzed with this program. RESULTS: In 111 of 115 cases (96.5%), this system produced the same results with the manual identification. In two cases, of not matched 4 cases the computer program suggested additional antibodies and in one case, the computer program detected previous human error. In the other case, antibody identification was possible only after further tests including selective adsorption of multiple antibodies. CONCLUSION: The decision support system was rapid and easy and showed good concordance rate when compared with manual antibody identificaion results. In addition, human error could be reduced. Decision support system for antibody identification could be used in small blood banks by less experienced staffs.

Analysis of antibodies causing hemolytic disease of the newborn / 대한수혈학회지

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.

Two Cases of Severe Hemolytic Transfusion Reactions Caused by Anti-Jkb Antibody / 대한수혈학회지

We report two patients who suffered from hemolytic transfusion reactions due to anti-Jkb antibody: one showed acute- and the other showed delayed-type hemolysis. The first patient was a 40-year-old man who suffered from epilepsy after the operation for arteriovenous malformation 16 years ago. He received five units of red blood cells (RBC) after right temporal lobectomy. On the fifteenth postoperative day, fever and chill developed during transfusion of one unit of packed RBC, followed by dark urine and oliguria. The polyethylene glycol-Coombs test and enzyme test revealed anti-Jkb antibody which had not been detected on the pretransfusion specimen. The second patient was a 41-year-old man who was admitted for the reoperation of the prosthetic mitral valve. Because hemoglobin was 5.9g/dL at admission, he received five units of packed RBCs. Oliguria and laboratory findings consistent with hemolytic anemia were observed from the third day of transfusion. Anti-Jkb antibody was detected on antiglobulin phase. Both patients developed acute renal failure (ARF) and hemodialysis with conservative management were done. They finally recovered from ARF without any residual complications. Implementation of more sensitive pretransfusion tests should be considered to prevent rare, but serious hemolytic transfusion reactions.

Experiences of U.K. Notionol Externol Quality Assessment Scheme for Blood Group Serology / 대한수혈학회지

The blood bank of the Seoul National University Hospital has joined the U.K. National External Quality Assessment Scheme(NEQAS) for Blood Group Serology since 1992. We reported correct answers on all occasions for thirty-six samples tested for ABO, RhD typing, and direct antiglobulin test. Among 36 antibody screening and antibody,,identification tests, we missed one anti-S. Among 96 crossmatchings, we made 4 major errors and one minor error. It was interesting that all of the major errors we made were from the sample delivered in mid-summer. Since the items included in the domestic program for the external quality control of blood group serology are very limited in Korea, joining any international quality control program will be necessary for larger blood banks to assure quality of varirous blood bank tests being performed.