A Study of the Molecular Characteristics of the Serologic D-- Blood Type in Korean Blood Donors / 대한수혈학회지

Background@#The Korean Red Cross has conducted serologic tests for C, c, E, e antigens and found 18 D-- donors.In this study, we performed RHCE genotyping to identify the molecular characteristics of the serologic D-- blood type in Korean blood donors. @*Methods@#We performed RHCE-specific PCR-based electrophoresis to check the amplification pattern of each exon.Sanger sequencing was conducted to find the variants in the nucleotide sequence. We determined the RHCE genotype based on the electrophoresis and Sanger sequencing results. @*Results@#Total eight out of 18 D-- donors were participated in this research. In the PCR-based electrophoresis tests, RHCE exons 3, 4, and 6 were not amplified in samples #4, #6, and #8. Also, sample #2 showed an abnormal band pattern of RHCE exon 9. The Sanger sequencing results showed that the nucleotide sequences of the RHCE exons 5, 7, and 8 in samples #4, #6 and #8 corresponded to the nucleotide sequences of RHD exons 5, 7, and 8, respectively, suggesting the possibility of a RHCE-RHD(3-8)-RHCE hybrid allele. The nucleotide sequences of RHCE exons 7 and 8 in sample #2 were the same as the nucleotide sequences of RHD exons 7 and 8, respectively.In samples #1, #3, #5, and #7, no specific variants known to cause D-- phenotype were found. @*Conclusion@#RHCE genes partially replaced by the RHD genes were found in four out of eight participants and three of them were identified as ?RHCE*02N.07, which is known as the RHCE null allele. A further study with complete RHCE sequencing could be helpful for an understanding of the molecular mechanisms of samples in which no significant variants were identified.

The Experience of RHD Genotyping in D-negative Blood Donors / 대한수혈학회지

Background@#There have been some domestic and overseas cases of anti-D alloimmunization caused by the transfusion of serologically D-negative blood. However, it is difficult to distinguish between true D-negative and DEL variants using conventional serologic typing. Therefore, we established the RHD genotyping algorithm for the detection of DEL variants and applied this algorithm to serologic D negative donors who voluntarily consented to testing. @*Methods@#From September 2016 to December 2020, 216 RHD negative donors who were C＋ and/or E+ in previous serologic typing were recruited. The screening test was PCR amplification of the RHD exons 4, 7, 10, and a promotor. Based on the results of PCR screening, true D-negative samples and RHD variants (including DEL) were discriminated. When the result was a RHD variant, exon 9 was sequenced to identify the nucleotide changes. Full sequencing was performed if no mutations were detected at exon 9. @*Results@#Among the 216 participants, 39 cases with the C−E−c＋e＋ phenotypes that did not meet the recruitment criteria were excluded from data analysis. Among the remaining 177 samples, 68 cases (38.4%) were RHD total deletions, 35 cases (19.8%) were RHD-CE-D hybrids, and 74 cases (41.8%) were RHD variants. Among the cases of RHD variants, 73 cases (98.6%) had c.1227G＞A substitutions and were confirmed as Asian-type DEL. @*Conclusion@#Seventy-four cases of serologic D negative donors were reclassified as RHD variants by RHD genotyping. This is believed to have contributed to the improvement of transfusion safety by lowering the risk of anti-D alloimmunization in D-negative patients.

Current Status of Korean Red Cross HLA-Matched Platelet Donor Registry / 대한수혈학회지

HLA-matched platelet transfusion is required for patients with platelet refractoriness due to HLA alloimmunity. From 2013 to 2019, the Korean Red Cross has recruited 4,080 donors for HLA-matched platelets. The patient’s HLA information should be submitted to the Korean Red Cross in accordance with the WHO HLA serologic specificities. When HLA-matched platelets are requested, the Korean Red Cross selects the appropriate donors based on Duquesnoy’s matching grade classification (1977) and CREGs defined by Takemoto, Fuller, and Rodey (2007) and then contacts them to request blood donations. Platelets of HLA-matched donors are collected by apheresis and supplied to the hospital. To make this process more efficient, the Korean Red Cross introduced a systemic standard work procedure using a computer program for blood donor management and HLA matching. Owing to the extensive polymorphism of the HLA types, expansion of the donor pool would be required to supply HLA-matched platelets sufficiently. As the number of registered donors for HLA-matched platelets is limited, it should only be ordered when the indication criteria for its use are met. The Korean Red Cross is planning to study genotype-based matching strategies for patients with rare HLA types and receive patients’ laboratory test results from medical institutions to evaluate the effectiveness of HLA-matched platelet transfusions.

The Experience of RHD Genotyping in D-negative Blood Donors / 대한수혈학회지

Background@#There have been some domestic and overseas cases of anti-D alloimmunization caused by the transfusion of serologically D-negative blood. However, it is difficult to distinguish between true D-negative and DEL variants using conventional serologic typing. Therefore, we established the RHD genotyping algorithm for the detection of DEL variants and applied this algorithm to serologic D negative donors who voluntarily consented to testing. @*Methods@#From September 2016 to December 2020, 216 RHD negative donors who were C＋ and/or E+ in previous serologic typing were recruited. The screening test was PCR amplification of the RHD exons 4, 7, 10, and a promotor. Based on the results of PCR screening, true D-negative samples and RHD variants (including DEL) were discriminated. When the result was a RHD variant, exon 9 was sequenced to identify the nucleotide changes. Full sequencing was performed if no mutations were detected at exon 9. @*Results@#Among the 216 participants, 39 cases with the C−E−c＋e＋ phenotypes that did not meet the recruitment criteria were excluded from data analysis. Among the remaining 177 samples, 68 cases (38.4%) were RHD total deletions, 35 cases (19.8%) were RHD-CE-D hybrids, and 74 cases (41.8%) were RHD variants. Among the cases of RHD variants, 73 cases (98.6%) had c.1227G＞A substitutions and were confirmed as Asian-type DEL. @*Conclusion@#Seventy-four cases of serologic D negative donors were reclassified as RHD variants by RHD genotyping. This is believed to have contributed to the improvement of transfusion safety by lowering the risk of anti-D alloimmunization in D-negative patients.

Current Status of Korean Red Cross HLA-Matched Platelet Donor Registry / 대한수혈학회지

HLA-matched platelet transfusion is required for patients with platelet refractoriness due to HLA alloimmunity. From 2013 to 2019, the Korean Red Cross has recruited 4,080 donors for HLA-matched platelets. The patient’s HLA information should be submitted to the Korean Red Cross in accordance with the WHO HLA serologic specificities. When HLA-matched platelets are requested, the Korean Red Cross selects the appropriate donors based on Duquesnoy’s matching grade classification (1977) and CREGs defined by Takemoto, Fuller, and Rodey (2007) and then contacts them to request blood donations. Platelets of HLA-matched donors are collected by apheresis and supplied to the hospital. To make this process more efficient, the Korean Red Cross introduced a systemic standard work procedure using a computer program for blood donor management and HLA matching. Owing to the extensive polymorphism of the HLA types, expansion of the donor pool would be required to supply HLA-matched platelets sufficiently. As the number of registered donors for HLA-matched platelets is limited, it should only be ordered when the indication criteria for its use are met. The Korean Red Cross is planning to study genotype-based matching strategies for patients with rare HLA types and receive patients’ laboratory test results from medical institutions to evaluate the effectiveness of HLA-matched platelet transfusions.

Requirement of Establishment of Frozen Blood Storage System for Management of Rare Blood Supply and Strategic National Stockpile / 대한수혈학회지

The blood supply can become disrupted in situations of increased demand during unexpected national catastrophes and when a patient needs a rare blood transfusion, which depends on the blood inventory in peacetime. Cryopreservation of blood, which can be stored up to 10 years, represents a possible solution to this problem by avoiding storage lesions. This review describes frozen red cell technologies, quality control issues related to post-thaw red blood cells, and preconditions and practical considerations for implementation of a frozen blood banking system in Korea.

Eleven-Year Experience of Clostridial Bacteremia at a Tertiary Care Hospital in South Korea / 대한임상미생물학회지

BACKGROUND: Clostridial bacteremia (CB) is the second most frequent anaerobic bacteremia, and CB patients show high mortality without prompt antimicrobial therapy. We retrospectively reviewed 11 years of CB cases in a tertiary care hospital to describe the clinical and microbiological characteristics of CB and to define the risk factors of fatal CB. METHODS: All patients with CB from January 2002 to December 2012 were included in the study. Age, sex, underlying diseases, antibiotic use, and clinical outcome were reviewed. Antibiotic therapy was classified as either 'appropriate' or 'inappropriate' based on the activity against Clostridium species. RESULTS: A total of 118 Clostridium isolates (0.79% of all blood culture isolates) were recovered from the blood cultures of 114 patients. The underlying conditions of patients with CB were neoplasm in 87 cases (76.3%), gastrointestinal symptoms in 84 cases (73.7%), diabetes in 17 cases (14.9%), and hemodialysis in six cases (5.3%). Of the 118 Clostridium isolates, C. perfringens was the most frequent species (42 isolates, 35.6%). Thirty-two patients (28.1%) showed polymicrobial bacteremia, which was most commonly combined with Escherichia coli. Two patients harbored more than two Clostridium species. 'Appropriate' antibiotics were given to 97 (85.1%) patients. The mortality rate of CB at days 2, 8, and 30 was 7.9% (9/114), 14.0% (16/114), and 26.3% (30/114), respectively. CONCLUSION: Neoplasm, especially in the gastrointestinal tract or of hematologic origin, and hemodialysis were considered to be risk factors of blood stream clostridial infection. Early appropriate antibiotic coverage of CB was not definitely associated with lower mortality in our study.