RHD genotyping is a useful adjunct to serologic testing. Although the use of RHD genotyping in the detection of Asia type DEL in serological D negative Koreans is gradually increasing, it is rarely requested for patients with a known weak D phenotype. This paper reports the first Korean case of a 52-year-old female patient with serologic weak D phenotype and weak D type 33 (c.520G>A at exon 4 of RHD) identified by RHD exon 1 to 10 sequencing. In silico analysis predicted that the RHD c.520G>A (V174M) results in a serologic weak D phenotype.
Asia ; Computer Simulation ; Exons ; Female ; Humans ; Korea ; Middle Aged ; Phenotype ; Serologic Tests

D antigens are clinically significant, and routine tests on the D antigen requires the inclusion of weak D testing, which is performed using indirect antihuman immunoglobulin methods. On the other hand, exact typing of the D type of an individual can be done more precisely with RHD genotyping, which is a useful tool in cases where the RHD gene is intact. The majority of weak-D or partial-D cases are from single nucleotide changes or hybridization of RHD and RHCE genes. Nevertheless, frameshift mutations can also result in weak or partial-D. The characteristics of a frameshift mutation is typically a change in protein product after a problematic mutation and early termination of transcription, leading into truncated protein products. This paper reports a D-variant case with RHD 711delC along with a review of the relevant literature. In addition, the results of software analysis are reported.
Frameshift Mutation ; Genotype ; Hand ; Immunoglobulins

BACKGROUND: Pretransfusion tests are essential for safe transfusions, but occasionally, part or all can be omitted when a transfusion is needed urgently in an emergency. The purpose of this study was to share the authors' experience of various pretransfusion test protocols in a tertiary referral hospital in Korea. METHODS: From July 2016 to June 2017, all transfusion cases at Samsung Medical Center were analyzed retrospectively. For each pretransfusion test protocol, the parameters regarding issue, return and disposal rate of blood products, occurrence of hemolytic transfusion adverse effect, and prescription frequency of each respective department and ordering site were analyzed. RESULTS: A total of 90,539 units of red blood cells, 24,814 units of fresh frozen plasmas, 24,758 units of single donor platelets, and 23,303 units of platelet concentrates were issued during the study period. Among them, 3.6%, 1.8%, 0.3%, and 0.4% of red blood cells, fresh frozen plasmas, single donor platelets, and platelet concentrates were issued according to the emergency transfusion protocols. When various pretransfusion test protocols were applied to issue blood products, there was no case in which an adverse hemolytic transfusion reaction was suspected. When compared with usual pretransfusion test protocol, all emergency transfusion protocols showed significantly higher return and wastage rates in red blood cells and fresh frozen plasmas. Platelets also had a higher return and wastage rate, but the difference was not significant. CONCLUSION: These results suggests that there is no different risk of adverse hemolytic transfusion reaction regardless the pre-transfusion protocols, but management about of the increased rate of return and wastage of blood products in emergency transfusions should be considered.
Blood Platelets ; Emergencies ; Erythrocytes ; Humans ; Korea ; Plasma ; Prescriptions ; Retrospective Studies ; Tertiary Care Centers* ; Tissue Donors ; Transfusion Reaction

Cis-AB and B(A) alleles encode an ABO enzyme with dual A and B glycosyltransferase activity. Although globally rare, the cis-AB phenotype is found relatively often in Korean, Japanese, and Chinese populations. Cases of the B(A) allele have been reported mostly in the Chinese population. Forward typing performed in a Cambodian woman with an ABO discrepancy demonstrated a strong reaction with anti-A and anti-B reagents, while there was no reaction with lectin anti-A 1. The anti-A 1 antibody was detected in reverse typing. Through ABO gene sequence analyses of exons 6 and 7, one of the alleles was identified as ABO*B.01. In contrast, the other allele harboring a c.803G＞C substitution was either ABO*cisAB.05 or ABO*BA.06 allele. The ABO*cisAB.05 and ABO*BA.06 alleles remain indistinguishable despite routine serological testing and ABO genotyping. To the best of the author’s knowledge, this is the first case report of these variants discovered in a Cambodian individual residing in Korea.

Weak D type 102 allele (RHD*01W.102) carrying a missense variant (c.73A＞T, p.Ile25Phe) in exon 1 of the RHD has not been reported in Koreans to date. This is the first report of the weak D type 102 allele in the Korean population. The proposita, a 35-year-old woman, showed a serological weak D phenotype in routine RhD typing. Sequencing of all 10 RHD exons and zygosity testing targeting the hybrid Rhesus box revealed this proposita to harbor the weak D type 102 allele, as well as an RHD deletion (RHD*01W.102/RHD*01N.01). Family studies showed that the weak D type 102 allele was also present in her father and older brother (both assumed to be RHD*01W.102/RHD*01) but not in her mother and oldest brother (both assumed to be RHD*01/RHD*01N.01). In silico analysis of the replacement of isoleucine by phenylalanine at position 25 was done with PolyPhen-2, SIFT, and PROVEAN. While PolyPhen-2 predicted the variant as benign, SIFT and PROVEAN predicted it as damaging and deleterious, respectively, suggesting RHD c.73A>T (I25F) as the cause of serologic weak D phenotype. This patient should be treated as D-negative, when transfusion is needed.

Weak D and partial D result in quantitative and qualitative changes in RhD protein expression respectively. It is difficult to discriminate weak D from partial D by serological tests alone. RHD genotyping is a useful method that complements serological results. A 64-year-old woman visited our hospital for microvascular decompression surgery. Her blood type was O, D negative by manual tube test and as per auto analyzer results (QWALYS-3 system; DIAGAST, France). Weak D and partial D tests were performed by using two different monoclonal anti-D reagents (Bioscot; Merck Millipore, UK; Bioclone; Ortho Clinical Diagnostics, USA) and a panel of nine monoclonal antibodies, including anti-D IgM and IgG (D-Screen; DIAGAST, France). However, these serological tests could not confirm the subtype of partial D. Therefore, sequencing of RHD exon 1 to 10 was additionally performed for the patient and the case was revealed to be partial DVI type 3.

Cis-AB and B(A) alleles encode an ABO enzyme with dual A and B glycosyltransferase activity. Although globally rare, the cis-AB phenotype is found relatively often in Korean, Japanese, and Chinese populations. Cases of the B(A) allele have been reported mostly in the Chinese population. Forward typing performed in a Cambodian woman with an ABO discrepancy demonstrated a strong reaction with anti-A and anti-B reagents, while there was no reaction with lectin anti-A 1. The anti-A 1 antibody was detected in reverse typing. Through ABO gene sequence analyses of exons 6 and 7, one of the alleles was identified as ABO*B.01. In contrast, the other allele harboring a c.803G＞C substitution was either ABO*cisAB.05 or ABO*BA.06 allele. The ABO*cisAB.05 and ABO*BA.06 alleles remain indistinguishable despite routine serological testing and ABO genotyping. To the best of the author’s knowledge, this is the first case report of these variants discovered in a Cambodian individual residing in Korea.

Weak D and partial D result in quantitative and qualitative changes in RhD protein expression respectively. It is difficult to discriminate weak D from partial D by serological tests alone. RHD genotyping is a useful method that complements serological results. A 64-year-old woman visited our hospital for microvascular decompression surgery. Her blood type was O, D negative by manual tube test and as per auto analyzer results (QWALYS-3 system; DIAGAST, France). Weak D and partial D tests were performed by using two different monoclonal anti-D reagents (Bioscot; Merck Millipore, UK; Bioclone; Ortho Clinical Diagnostics, USA) and a panel of nine monoclonal antibodies, including anti-D IgM and IgG (D-Screen; DIAGAST, France). However, these serological tests could not confirm the subtype of partial D. Therefore, sequencing of RHD exon 1 to 10 was additionally performed for the patient and the case was revealed to be partial DVI type 3.

BACKGROUND: Although testing to detect weak D antigens using the antihuman globulin reagent is not required for D− patients in many countries, it is routinely performed in Korea. However, weak D testing can be omitted in D− patients with a C−E− phenotype as this indicates complete deletion of the RHD gene, except in rare cases. We designed a new algorithm for weak D testing, which consisted of RhCE phenotyping followed by weak D testing in C+ or E+ samples, and compared it with the current algorithm with respect to time and cost-effectiveness. METHODS: In this retrospective study, 74,889 test results from January to July 2017 in a tertiary hospital in Korea were analyzed. Agreement between the current and proposed algorithms was evaluated, and total number of tests, time required for testing, and test costs were compared. With both algorithms, RHD genotyping was conducted for samples that were C+ or E+ and negative for weak D testing. RESULTS: The algorithms showed perfect agreement (agreement=100%; κ=1.00). By applying the proposed algorithm, 29.56% (115/389 tests/yr) of tests could be omitted, time required for testing could be reduced by 36% (8,672/24,084 min/yr), and the test cost could be reduced by 16.53% (536.11/3,241.08 USD/yr). CONCLUSIONS: Our algorithm omitting weak D testing in D− patients with C−E− phenotype may be a cost-effective testing strategy in Korea.
Cost-Benefit Analysis ; Humans ; Korea ; Phenotype* ; Retrospective Studies ; Tertiary Care Centers