Results of the HLA Typing Proficiency Survey in Korea, 2000-2002 / 대한진단검사의학회지

BACKGROUND: HLA proficiency survey was started in 1996 in Korea, and the results of the 1996-1998 surveys were reported previously. Here, we report the results of the surveys performed in recent three years (2000-2002). METHODS: Six surveys were carried out with the participation of 52-54 laboratories. For each survey, 3 peripheral blood samples and 2 sera were distributed for 3 HLA class I serology, 3 HLA class I DNA, 3 HLA class II DNA, 6 HLA crossmatch, and 3 PRA tests. RESULTS: Overall consensus of serologic typing was similar to the results of the previous survey: HLA-A 93.5%, HLA-B 88.3%, and HLA-A, B 82.7%. There were an increasing number of the laboratories that were using DNA typing for HLA-DR (51 laboratories, 94%) and HLA-A and B (26 laboratories, 48%). Overall consensus of DNA typing was very high: HLA-A 100%, HLA-B 99.1%, HLAC 97.9%, HLA-DRB1 low/high resolution 99.2/99.0%, HLA-DQB1 low/high resolution 99.3/97.5%. HLA crossmatch (T cells) was reported by 44-49 laboratories, and the use of sensitive methods was increased: AHG 33 laboratories and flow cytometry 7 laboratories. For incompatible (positive) crossmatches, 4.9% (0-14.3%) of cytotoxicity tests and 7.1% (0-16.7%) of flow tests were reported as negative. PRA was reported by 5 laboratories only. CONCLUSIONS: The use of DNA tests for HLA typing and AHG or flow cytometry methods for HLA crossmatch tests has much increased compared to the previous report. A continuous survey program would play an important role in the standardization and maintenance of laboratory proficiency in histocompatibility testing in Korea.

Unusual Phenotype Expression in a Cis-AB Trait: Cis-AB Child from a Group A Father and a Group O Mother / 대한수혈학회지

Cis-AB (A2B3) is a rare genotype resulting from the inheritance of both A and B genes on one chromosome. Among possible genotypes of cis-AB, in individuals with O/cis AB and A1/cis-AB, the B antigen is usually weakly expressed. Study on a blood sample from a 13-year-old Korean girl showed a discrepancy between red blood cell and serum typing. The blood type was identified as AweakB on the red cell test, while weak anti-B was detected in the serum. Cis-AB (A2B3) was suspected, however, known blood types of her father and mother were A and O, respectively. In the repeated test, the propositus was typed as group A2B3. Her mother was typed as normal group O. Her father was typed as group A1 in cell typing, but in his serum, anti-B was very weakly detected. In the saliva test and adsorption and elution studies of the father, B substance was not detected. Finally, ABO genotyping was performed and ABO genotypes of the patient, mother and father were cisAB/O, O/O and cisAB/A1, respectively. This was the first reported case of A1/cisAB with phenotype A1. ABO genotyping technique will resolve problems encountered in association with unusual phenotype expression of cis-AB trait.

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

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 O RBCs into A or B cells. RESULTS: Determination of serum ABO transferase activity was useful in the identification of Ael (3 cases), B3 (2 cases), Bm (1 case), Am (1 case), Bx (1 case), O 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.

A Case of Group O without Anti-A,B due to hypogammaglobuluinemia / 대한수혈학회지

An ABO discrepancy was observed in a 19-year-old man clinically diagnosed as congenital hypogammaglobulinemia. The patient's red cell was typed as group O, and his serum had no ABO isoagglutinins. Absence of A antigen and B antigen on patient's RBC was confirmed by adsorption- elution test and saliva test. A-transferase and B-transferase activities were not demonstrated in patient's serum. Patient's serum protein electrophoresis revealed hypogammaglobulinemia pattern, and immunoglobulin levels were markedly decreased. Complete absence of B lymphocytes was observed on patient's lymphocyte subset profile. Patient's father and mother were typed as blood group O and no abnormalities were recognized in their serum protein electrophoresis patterns and immunoglobulin concentration.

Clinical Usefulness of Emergency Blood Donor Test / 대한수혈학회지

There are some emergency situations when untested fresh blood should be transfused. Emergency blood donor tests(EBDT) have been done as an effort to protect these blood recipients from contracting transfusion associated infections in Seoul National University, Hospital. EBDT includes HBsAg, anti-HlV, STS, and ALT test. Anti-HCV test is not included because of the absence of appropriate test kit. A total of 534 tests have been done from June 1993 to August 1995. Among these, 495 tests(92.7%) have been done for blood donor screening, and 39 tests(7.3%) for emergency organ transplantation. Sensitivity and specificiy of the emergency HBsAg test were 69% and 98%, respectively. There were two RPR reactive blood donors, but no anti-HIV positive cases. Among 458 blood donors, 37 donors(8.1%) showed increased ALT level(> 45IU/L). The percent of agreement in HBsAg, elevated ALT and anti-HIV tests between emergent and routine blood donor tests, were 97.0%, 98.9% and 100%, respectively. Although false positive and false negative EBDT result may is useful, although limited, we think that EBDT is useful in protecting blood recipient from transfusion associated infections.

A Family with -D- Phenotype Associated with Fatal Hemolytic Disease of the Newborn / 대한수혈학회지

-D- is a very rare haplotype which determines D without C, c, E or e and exalted D activity. The extremely rare homozygote propositi(-D-/-D-) are usually ascertained through their immune antibodies which react with red cells of all common Rh phenotypes. Authors experienced a woman with -D- phenotype for the first time in Korea. She had a history of abortion and intrauterine fetal death. She delivered a baby with severe hemolytic disease of the newborn at the third pregnancy. In spite of intensive medical interventions, the baby died of hydrops fetalis. An immune antibody to high incidence Rh antigen, namely anti-Hro, was demonstrated in the woman's serum. Family study revealed that all of the family had -D- gene complex and one of her sisters also was -D-homozygote. The sister also had anti-Hro in the serum.