Clinical Practice Guideline for Blood-based Circulating Tumor DNA Assays

Circulating tumor DNA (ctDNA) has emerged as a promising tool for various clinical applications, including early diagnosis, therapeutic target identification, treatment response monitoring, prognosis evaluation, and minimal residual disease detection. Consequently, ctDNA assays have been incorporated into clinical practice. In this review, we offer an in-depth exploration of the clinical implementation of ctDNA assays. Notably, we examined existing evidence related to pre-analytical procedures, analytical components in current technologies, and result interpretation and reporting processes. The primary objective of this guidelines is to provide recommendations for the clinical utilization of ctDNA assays.

Characterization of novel HLA-A*24:608N allele discovered in Koreans

A novel null HLA-A*24 allele, HLA-A*24:608N, was identified in five Korean subjects including three from a family and two separate individuals. This study was performed to discern its immunological function in transplantation settings. Because this null variant had deletions of approximately 12 k base pairs from intron 3 to 3' end of the HLA-A gene, low resolution HLA typing and amplicon-based next generation sequencing (NGS) typing methods had failed to assign it. Hybrid capture-based NGS method confirmed that this novel variant had a large deletion. T-lymphocyte crossmatching by complement-dependent lymphocytotoxicity and flow cytometry with a serum consisting anti-HLA-A24 antibody revealed negative results, implying that an individual with this allele would not carry a functioning A24 antigen. These findings highlight the importance of identifying a null HLA allele by employing appropriate molecular method and providing expected crossmatching outcomes in a real-world transplantation setting.

Association Between Low Anti-spike Antibody Levels After the Third Dose of SARS-CoV-2 Vaccination and Hospitalization due to Symptomatic Breakthrough Infection in Kidney Transplant Recipients

Background

Whether anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels post-third coronavirus disease (COVID-19) vaccination correlate with worse outcomes due to breakthrough infection is unclear. We evaluated the association between anti-SARS-CoV-2 antibody levels and symptomatic breakthrough infection or hospitalization during the Omicron surge in kidney transplant recipients.

Methods

In total, 287 kidney transplant recipients expected to receive a third vaccination were enrolled between November 2021 and February 2022. The Abbott SARS-CoV-2 IgG II Quant test (Abbott, Chicago, IL, USA) was performed within three weeks before and four weeks after the third vaccination. The incidence of symptomatic breakthrough infection and hospitalization from two weeks to four months post-third vaccination was recorded.

Results

After the third vaccination, the seropositive rate and median antibody titer of the 287 patients increased from 57.1% to 82.2% and from 71.7 (interquartile range [IQR] 7.2-402.8) to 1,612.1 (IQR 153.9-5,489.1) AU/mL, respectively. Sixty-four (22.3%) patients had symptomatic breakthrough infections, of whom 12 required hospitalization. Lower anti-receptor-binding domain (RBD) IgG levels (<400 AU/mL) post-third vaccination were a risk factor for symptomatic breakthrough infection (hazard ratio [HR]=3.46, P<0.001). Anti-RBD IgG levels <200 AU/mL were a critical risk factor for hospitalization (HR=36.4, P=0.007).

Conclusions

Low anti-spike IgG levels after third vaccination in kidney transplant recipients were associated with symptomatic breakthrough infection and, particularly, with hospitalization during the Omicron surge. These data can be used to identify patients requiring additional protective measures, such as passive immunization using monoclonal antibodies.

Comparison of Four T-cell Assays and Two Binding Antibody Assays in SARS-CoV-2 Vaccinees With or Without Omicron Breakthrough Infection

Background

Several T-cell response assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are available; however, their comparability and correlations with antibody responses remain unclear. We compared four SARS-CoV-2 T-cell response assays and two anti-SARS-CoV-2 spike antibody assays.

Methods

We enrolled 89 participants who had received a booster dose of the BNT162b2 vaccine after two doses of the ChAdOx1 or BNT162b2 vaccine. Fifty-six participants without breakthrough infection (BI) (ChAdOx1/BNT162b2 group: N=27; BNT162b2 group: N=29) and 33 with BI were included. We evaluated two whole-blood interferon-gamma release assays (IGRAs) (QuantiFERON and Euroimmun), T-SPOT.COVID, an in-house enzyme-linked immunospot (ELISPOT) assay (targeting the spike and nucleocapsid peptides of wild-type and Omicron SARS-CoV-2), Abbott IgG II Quant, and Elecsys Anti-S, using Mann-Whitney U, Wilcoxon signed-rank, and Spearman's correlation tests.

Results

The correlations between the IGRAs and between the ELISPOT assays (ρ=0.60-0.70) were stronger than those between the IGRAs and ELISPOT assays (ρ=0.33-0.57). T-SPOT.COVID showed a strong correlation with Omicron ELISPOT (ρ=0.70). The anti-spike antibody assays showed moderate correlations with T-SPOT.COVID, Euroimmun IGRA, and ELISPOT (ρ=0.43-0.62). Correlations tended to be higher in the BI than in the noninfected group, indicating that infection induces a stronger immune response.

Conclusions

T-cell response assays show moderate to strong correlations, particularly when using the same platform. T-SPOT.COVID exhibits potential for estimating immune responses to the Omicron variant. To accurately define SARS-CoV-2 immune status, both T-cell and B-cell response measurements are necessary.

Allele and haplotype frequencies of 11 HLA loci in Koreans by next-generation sequencing

Data on HLA genotype distribution, including DQA1 and DPA1, in the Korean population are limited. We aimed to investigate the allele and haplotype frequencies of 11 HLA loci in 339 Korean subjects using next-generation sequencing (NGS)-based HLA typing. A total of 339 samples from unrelated healthy subjects were genotyped for HLA-A, -B, -C, -DRB1, -DRB3, -DRB4, -DRB5, -DQB1, -DQA1, -DPB1, and -DPA1 using two different NGS-based HLA typing kits (166 tested using the NGSgo-MX11-3 kit [GenDx, Netherlands] and 173 by the AllType NGS 11 Loci Amplification kit [One Lambda, USA]). PyPop software was used to estimate allele and haplotype frequencies and linkage disequilibrium between the loci. Additionally, a principal component analysis was performed to compare the allele distribution of Koreans with that of other populations. A total of 214 HLA alleles (97 class I and 117 class II alleles) were assigned. The most frequent alleles for each locus were A*24:02:01 (24.78%), B*15:01:01 (10.18%), C*01:02:01 (18.44%), DRB1*04:05:01 (9.59%), DRB3*02:02:01 (13.72%), DRB4*01:03:01 (25.81%), DRB5*01:01:01 (9.0%), DQA1*01:02:01 (16.96%), DQB1*03:01:01 (14.31%), DPA1*01:03:01 (44.4%), and DPB1*05:01:01 (35.1%), respectively. The most frequent haplotypes were A*33:03:01-C*03:02:02-B*58:01:01 for HLA class I (5.01%) and DRB1*04:05:01-DQA1*03:03:01-DQB1*04:01:01-DPA1*02:02:02-DPB1*05:01:01 for HLA class II (6.23%). The total allelic ambiguities by NGS were estimated to be minimal and considerably decreased compared with those by Sanger sequencing. The Japanese population had the most similar allele distribution to Koreans, followed by the Chinese population. Frequency data of 11 HLA loci in Koreans can provide essential data for population genetics and disease association studies.

Clinical Significances of Anti-Collagen Type I and Type III Antibodies in Antibody-Mediated Rejection

It is important to determine the clinical significance of non-human leukocyte antigen (HLA) antibodies and their association with antibody-mediated rejection (ABMR) of kidney allografts. We collected post-transplant sera from 68 ABMR patients, 67 T-cell mediated rejection (TCMR) patients, and 83 control subjects without rejection, and determined the titers of 39 non-HLA antibodies including antibodies for angiotensin II receptor type I and MICA. We compared all these non-HLA antibody titers among the study groups. Then, we investigated their association with the risk of death-censored graft failure in ABMR cases. Among the antibodies evaluated, anti-collagen type I (p = 0.001) and type III (p < 0.001) antibody titers were significantly higher in ABMR cases than in both TCMR cases and no-rejection controls. Both anti-collagen type I [per 1 standard deviation (SD), adjusted odds ratio (OR), 11.72 (2.73-76.30)] and type III [per 1 SD, adjusted OR, 6.22 (1.91-31.75)] antibodies were significantly associated with the presence of ABMR. Among ABMR cases, a higher level of anti-collagen type I [per 1 SD, adjusted hazard ratio (HR), 1.90 (1.32-2.75)] or type III per 1 SD, [adjusted HR, 1.57 (1.15-2.16)] antibody was associated with a higher risk of death-censored graft failure. In conclusion, post-transplant anti-collagen type I and type III antibodies may be novel non-HLA antibodies related to ABMR of kidney allografts.

Differences in the diagnosis and treatment of hematologic malignancies attributable to health insurance coverage

Medical care should be equally provided to the public regardless of their financial capability. In the real world, expenditures directly out from the patient sector decide the medical journey, even in a country with national health insurance. The aim of this study was to investigate whether there are differences in the diagnostic and treatment processes in hematologic malignancies based on patient characteristics, such as health insurance status.Through the review of 5614 "CBCs with differential count" results with abnormal cells from 358 patients from January 2010 to June 2017, 238 patients without past medical histories of hematologic malignancies were enrolled. Excluding reactive cases, 206 patients with hematologic malignancy were classified into 8 disease categories: acute leukemia, myelodysplastic syndrome, myeloproliferative neoplasm (MPN), myelodysplastic syndrome/MPN, lymphoid neoplasm, plasma cell neoplasm, r/o hematologic malignancy, and cancer.The patients' age, sex, disease categories and follow-up durations showed associations with the clinical course. The "refusal of treatment" group was the oldest and had a relatively higher percentage of females, whereas those who decided to transfer to a tertiary hospital were younger. The age, clinical course, and follow-up durations were different across health insurance statuses. The medical aid group was the oldest, and the group whose status changed from a medical insurance subscriber to a medical aid beneficiary during treatment was the youngest. The majority of patients who refused treatment or wished to be transferred to a tertiary hospital were medical insurance subscribers. The percentage of patients who were treated in this secondary municipal hospital was higher in the medical-aid beneficiaries group than in the medical insurance group. Follow-up durations were longest in the status change group and shortest in the medical insurance group.Almost all medical aid beneficiaries with hematologic malignancies opted to continue treatment at this secondary/municipal hospitals, indicating that this category of medical institutions provides adequate levels and qualified healthcare services to those patients. The secondary municipal hospital provides qualified healthcare services for medical aid beneficiaries with hematologic malignancies.

SARS-CoV-2 Omicron Mutation Is Faster than the Chase: Multiple Mutations on Spike/ACE2 Interaction Residues

Recently, a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (B.1.1.529) Omicron variant originated from South Africa in the middle of November 2021. SARS-CoV-2 is also called coronavirus disease 2019 (COVID-19) since SARS-CoV-2 is the causative agent of COVID-19. Several studies already suggested that the SARS-CoV-2 Omicron variant would be the fastest transmissible variant compared to the previous 10 SARS-CoV-2 variants of concern, interest, and alert. Few clinical studies reported the high transmissibility of the Omicron variant but there is insufficient time to perform actual experiments to prove it, since the spread is so fast. We analyzed the SARS-CoV-2 Omicron variant, which revealed a very high rate of mutation at amino acid residues that interact with angiostatin-converting enzyme 2. The mutation rate of COVID-19 is faster than what we prepared vaccine program, antibody therapy, lockdown, and quarantine against COVID-19 so far. Thus, it is necessary to find better strategies to overcome the current crisis of COVID-19 pandemic.

Association of HLA-DRB1 and -DQB1 Alleles with Susceptibility to IgA Nephropathy in Korean Patients

Background

Associations between IgA nephropathy (IgAN) and HLA-DRB1 and -DQB1 alleles have been reported in several ethnic groups. We investigated the association of HLA-DRB1 and -DQB1 alleles with the predisposition for IgAN and disease progression to end-stage kidney disease (ESKD) in Korean patients.

Methods

We analyzed HLA-DRB1 and -DQB1 genotypes in 399 IgAN patients between January 2000 and January 2019 using a LIFECODES sequence-specific oligonucleotide (SSO) typing kit (Immucor, Stamford, CT, USA) or a LABType SSO Typing Test (One Lambda, Canoga Park, CA, USA). Alleles with a significant difference in two-digit resolution were further analyzed using in-house sequence-based typing and sequence-specific primer PCR. As controls, 613 healthy hematopoietic stem cell donors were included. Kidney survival was analyzed in 281 IgAN patients with available clinical and laboratory data using Cox regression analysis. Where needed, P-values were adjusted using Bonferroni correction.

Results

The allele frequencies of HLA-DRB1*0405 (corrected P [Pc]<0.001), -DQB1*0401 (Pc=0.048), and -DQB1*0302 (Pc=0.021) were significantly higher in IgAN patients than in controls, whereas those of HLA-DRB1*0701, -DRB1*1501, -DQB1*0202, and -DQB1*0602 (Pc<0.001 for all) were significantly lower in IgAN patients than in controls. The allele frequency of HLA-DQB1*0503 (Pc=0.016) was significantly lower in the ESKD group than in the non-ESKD group; however, there was no significant difference for ESKD progression between these groups.

Conclusions

We report novel associations of HLA-DRB1*1501, DQB1*0202, -DQB1*0302, and -DQB1*0401 with IgAN. Further studies of HLA alleles associated with IgAN progression in a larger cohort and in various ethnic groups are needed.

Reducing severe cutaneous adverse and type B adverse drug reactions using pre-stored human leukocyte antigen genotypes

BACKGROUND

Several type B adverse drug reactions (ADRs), especially severe cutaneous adverse reactions (SCARs), are associated with particular human leukocyte antigen (HLA) genotypes. However, pre-stored HLA information obtained from other clinical workups has not been used to prevent ADRs. We aimed to simulate the preemptive use of pre-stored HLA information in electronic medical records to evaluate whether this information can prevent ADRs.

METHODS

We analyzed the incidence and the risk of ADRs for selected HLA alleles (HLA-B*57:01, HLA-B*58:01, HLA-A*31:01, HLA-B*15:02, HLA-B*15:11, HLA-B*13:01, HLA-B*59:01, and HLA-A*32:01) and seven drugs (abacavir, allopurinol, carbamazepine, oxcarbazepine, dapsone, methazolamide, and vancomycin) using pre-stored HLA information of transplant patients based on the Pharmacogenomics Knowledge Base guidelines and experts' consensus.

RESULTS

Among 11,988 HLA-tested transplant patients, 4092 (34.1%) had high-risk HLA alleles, 4583 (38.2%) were prescribed risk drugs, and 580 (4.8%) experienced type B ADRs. Patients with HLA-B*58:01 had a significantly higher incidence of type B ADR and SCARs associated with allopurinol use than that of patients without HLA-B*58:01 (17.2% vs. 11.9%, odds ratio [OR] 1.53 [95% confidence interval {CI} 1.09-2.13], p = 0.001, 2.3% versus 0.3%, OR 7.13 [95% CI 2.19-22.69], p < 0.001). Higher risks of type B ADR and SCARs were observed in patients taking carbamazepine or oxcarbazepine if they had one of HLA-A*31:01, HLA-B*15:02, or HLA-B*15:11 alleles. Vancomycin and dapsone use in HLA-A*32:01 and HLA-B*13:01 carriers, respectively, showed trends toward increased risk of type B ADRs.

CONCLUSION

Utilization of pre-stored HLA data can prevent type B ADRs including SCARs by screening high-risk patients.

Performance evaluation of three automated quantitative immunoassays and their correlation with a surrogate virus neutralization test in coronavirus disease 19 patients and pre-pandemic controls

Background

SARS‐CoV‐2 pandemic is currently ongoing, meanwhile vaccinations are rapidly underway in some countries. The quantitative immunoassays detecting antibodies against spike antigen of SARS‐CoV‐2 have been developed based on the findings that they have a better correlation with the neutralizing antibody.

Methods

The performances of the Abbott Architect SARS‐CoV‐2 IgG II Quant, DiaSorin LIAISON SARS‐CoV‐2 TrimericS IgG, and Roche Elecsys anti‐SARS‐CoV‐2 S were evaluated on 173 sera from 126 SARS‐CoV‐2 patients and 151 pre‐pandemic sera. Their correlations with GenScript cPass SARS‐CoV‐2 Neutralization Antibody Detection Kit were also analyzed on 173 sera from 126 SARS‐CoV‐2 patients.

Results

Architect SARS‐CoV‐2 IgG II Quant and Elecsys anti‐SARS‐CoV‐2 S showed the highest overall sensitivity (96.0%), followed by LIAISON SARS‐CoV‐2 TrimericS IgG (93.6%). The specificities of Elecsys anti‐SARS‐CoV‐2 S and LIAISON SARS‐CoV‐2 TrimericS IgG were 100.0%, followed by Architect SARS‐CoV‐2 IgG II Quant (99.3%). Regarding the correlation with cPass neutralization antibody assay, LIAISON SARS‐CoV‐2 TrimericS IgG showed the best correlation (Spearman rho = 0.88), followed by Architect SARS‐CoV‐2 IgG II Quant and Elecsys anti‐SARS‐CoV‐2 S (all rho = 0.87).

Conclusions

The three automated quantitative immunoassays showed good diagnostic performance and strong correlations with neutralization antibodies. These assays will be useful in diagnostic assistance, evaluating the response to vaccination, and the assessment of herd immunity in the future.

Umbilical Cord Blood Units Cryopreserved in the Public Cord Blood Bank: A Breakthrough in iPSC Haplobanking?

The use of induced pluripotent stem cells (iPSCs) is an emerging therapeutic option for precision medicine. Cord blood (CB) cells with lower immunogenicity, fewer genomic changes, and persistent epigenetic memory might be ideal candidates for iPSC production. Based on the human leukocyte antigen (HLA) distribution of cord blood units (CBUs) in the public CB bank, we estimated the coverage of the Korean population with HLA-homozygous iPSCs to repurpose cryopreserved CBUs. We analyzed a total of 27,904 Korean CBUs donated to the public CB bank. Low-to-intermediate resolution typing was performed for HLA-A, -B, and -DRB1 alleles, and individuals possessing homozygous HLA haplotypes were identified by direct counting. Moreover, the matching probabilities for zero-mismatch transplantation were calculated for 27,904 CBUs and 50,000,000 potential Korean patients. Among the preserved CBUs, 15 HLA-A, 40 HLA-B, and 13 HLA-DRB1 alleles as well as 48 homozygous HLA-A-B-DRB1 haplotypes were identified at serological equivalents (2 digits). The 48 identified homozygous haplotypes cumulatively matched 78.18% of the 27,904 Korean CB donors as zero HLA-mismatch iPSC sources. Among the combinations of 1,699 haplotypes with frequencies greater than 0.001%, assuming a population of 50 million, those 48 haplotypes can provide a match for 78.37% of potential Korean recipients. A practicable number of HLA-A, -B, and -DRB1 homozygous iPSC lines derived from CBUs may be an efficient option in allogeneic iPSC therapy because this type of haplobanking may provide cell lines with optimal HLA matching for up to three-quarters of the Korean population.

Evaluation of LabType-SSO HLA Typing for HLA-A, -B, -C, -DRB1, and -DQB1 loci

BACKGROUND

For HLA genotyping, PCR sequence-specific oligonucleotide (SSO) methods using the Luminex platform are widely used. We evaluated the performance of LabType-SSO (One Lambda, USA) in Koreans.

METHODS

LabType-SSO were performed on 50 residual DNA samples analyzed by sequence-based typing (SBT) for all HLA-A, -B, -C, -DRB1, and -DQB1 alleles with gene frequency > 0.1% in Koreans.

RESULTS

The LabType-SSO results were in complete agreement with SBT at the 2-digit level. For 4-digit level, 9 HLA-A alleles, 1 HLA-B allele, 3 HLA-C alleles, neither HLA-DRB1 nor -DQB1 allele showed ambiguous results for assignment of most probable types considering HLA gene frequency in Koreans. In addition, two cases of DQB1*04:01 allele were incorrectly assigned to DQB1*04:02.

CONCLUSIONS

LabType-SSO tests showed accurate assignment of 2-digit level and LabType-SSO HLA-DRB1 test showed correct 4-digit most probable HLA type. The tests can be useful as intermediate resolution typing for solid organ transplantation.

Role of the IL-33/ST2 pathway in renal allograft rejection

The interleukin-33 (IL-33)/suppression of tumorigenicity 2 (ST2) pathway modulates immune response and inflammation, associated with allograft dysfunction and rejection. We hypothesized that IL-33/ST2 is a marker of renal allograft rejection and IL-33/ST2 expression may differ according to rejection type. IL-33/ST2 expression was measured in sera and kidney tissues from recipients with acute antibody-mediated rejection (AAMR), acute cell-mediated rejection (ACMR), chronic antibody-mediated rejection (CAMR), and healthy controls. The soluble ST2 and IL-33/ST2 expression levels were higher in participants with all three rejection types than in controls. Although the expression levels in recipients with AAMR and ACMR were significantly higher than those with CAMR, there was no significant difference between the expression levels in AAMR and ACMR. Although IL-33, IL-8, and fibronectin expression were significantly increased after the addition of the recipients' serum in primary cultured human renal proximal tubular epithelial cells, the levels decreased after treatment with an anti-ST2 antibody. Furthermore, the anti-ST2 antibody specifically suppressed the upregulation of the mixed lymphocyte reaction. Boyden chamber assays demonstrated that anti-ST2 antibody abrogated chemotaxis induced by recombinant IL-33. Thus, IL-33 and ST2 are potent mediators of rejection. Treatment with an anti-ST2 antibody ameliorates rejection and could be a potential therapeutic strategy for renal allograft rejection.

Performance evaluation of immunoassay for infectious diseases on the Alinity i system

Background

Although a diagnosis of infectious diseases is essential for timely treatment, the performance of diagnostic tests has been hardly evaluated due to variable results that are influenced by multiple factors in different conditions. In the present study, the performance of the Alinity i system, which is a newly developed immunoassay to diagnose infectious diseases, was evaluated.

Methods

We evaluated the precision, linearity, correlation, and carryover of 16 analytes (HAV Ab IgG, HBsAg, HBeAg, anti‐HBc, anti‐HBe, anti‐HBs, anti‐HCV, HIV Ag/Ab, EBV VCA IgM, EBV VCA IgG, EBV EBNA IgG, CMV IgM, CMV IgG, Toxoplasma IgG, Rubella IgG, and Syphilis TP) of Alinity i by comparison with ARCHITECT i2000_SR system following the rationale of the Clinical and Laboratory Standards Institute (CLSI).

Results

For quantitative tests, the coefficients of variation (CV) % of repeatability and intermediate precision were between 0% and 4.18%. The coefficients of the linearity (r²) over a widely tested analytical range were ≥ 0.990 and the correlation between Alinity i and the ARCHITECT i2000_SR system was strong (r ≥ 0.994). For qualitative tests, the agreement between Alinity i and the ARCHITECT i2000_SR system was excellent (kappa coefficient 1) with 100% sensitivity and specificity. Carryover rates for all analytes were less than 1.0% (−0.11% ~ 0.21%).

Conclusion

The Alinity i system showed good analytical performance and favorable comparability with the ARCHITECT i2000_SR. It could be suitable as a routine immunoassay analyzer for screening and diagnosis of infectious disease.

Total nucleated cell counts are driving clinician's choice rather than cryopreservation period: Lesson for cord blood banks

According to the increase in both the number of cryopreserved cord blood (CB) units and the cryopreservation period for each CB unit in the largest public CB bank in Korea, we are pursuing greater efficiency in CB bank management. Thus, we analyzed whether the cryopreservation period has a negative impact on the selection of CB units for CB transplantation (CBT). Until December 2019, 468 CB units were used for transplantation. The cryopreservation period, total nucleated cell (TNC), and CD34+ cell counts were analyzed among the CB units according to the CBT-year and the donation year. The results showed that the cryopreservation period was increased in recent CBT-year groups. The transplanted CB units showed similar TNC counts irrespective of the donation year, and the mean TNC count was 13.9 × 108/unit. CB units cryopreserved for a relatively long period were transplanted consistently. The mean TNC count of CB units cryopreserved for over 10 years was 16.4 × 108/unit. The mean CD34+ cell counts were not significantly different among the CB units transplanted after CBT-2013 and among the CB units donated after CBT-2011. Through an analysis of the CB units selected by clinicians for CBT, this study revealed that clinicians placed more weight on the TNC counts than on the cryopreservation period of cryopreserved CB units. Therefore, the minimum TNC count of CB units suitable for cryopreservation should be increased up to 13.0 × 108/unit to balance the satisfaction of clinicians' needs with the efficiency of the CB bank.

Usefulness of the Hematopoietic Stem Cell Donor Pool as a Source of HLA-Homozygous Induced Pluripotent Stem Cells for Haplobanking: Combined Analysis of the Cord Blood Inventory and Bone Marrow Donor Registry

Induced pluripotent stem cells (iPSCs) have opened up unprecedented opportunities for novel therapeutic options for precision medicine. Hematopoietic stem cell (HSC) donor pools with previously determined HLA types may be ideal sources for iPSC production. Based on the HLA distribution of cryopreserved cord blood units (CBUs) and registered bone marrow (BM) donors, we estimated how much of the Korean population could be covered by HLA-homozygous iPSCs. We analyzed a total of 143,866 Korean HSC donors (27,904 CBUs and 115,962 BM donors). Each donor sample was typed for the HLA-A, -B, and -DRB1 alleles at low to intermediate resolution by DNA-based molecular techniques: PCR sequence-specific oligonucleotide (PCR-SSOP), PCR with sequence-specific primers (PCR-SSP) and PCR with sequence-based typing (PCR-SBT). We also identified individuals possessing homozygous HLA haplotypes by direct counting. The matching probabilities for zero-mismatch transplantation were calculated for 143,866 Koreans and 50 million potential Korean patients. Among the HSC donor pool, 17 HLA-A alleles, 41 HLA-B alleles, and 13 HLA-DRB1 alleles, as well as 128 homozygous HLA-A-B-DRB1 haplotypes, were identified at serologic equivalents, and those haplotypes cumulatively matched 93.20% of the 143,866 Korean donors as zero HLA-mismatch iPSC sources. Among the combinations of 2,056 haplotypes with frequencies ≥ 0.001% in a population of 50 million, those 128 homozygous haplotypes can provide 93.65% coverage for potential Korean recipients. Haplobanking of a reasonable number of HLA-A, -B, and -DRB1 homozygous iPSC lines derived from CBUs and cells of registered BM donors may be an efficient option for allogenic iPSC therapy.

Extracting Structured Genotype Information from Free-Text HLA Reports Using a Rule-Based Approach

BACKGROUND

Human leukocyte antigen (HLA) typing is important for transplant patients to prevent a severe mismatch reaction, and the result can also support the diagnosis of various disease or prediction of drug side effects. However, such secondary applications of HLA typing results are limited because they are typically provided in free-text format or PDFs on electronic medical records. We here propose a method to convert HLA genotype information stored in an unstructured format into a reusable structured format by extracting serotype/allele information.

METHODS

We queried HLA typing reports from the clinical data warehouse of Seoul National University Hospital (SUPPREME) from 2000 to 2018 as a rule-development data set (64,024 reports) and from the most recent year (6,181 reports) as a test set. We used a rule-based natural language approach using a Python regex function to extract the 1) number of patients in the report, 2) clinical characteristics such as indication of the HLA testing, and 3) precise HLA genotypes. The performance of the rules and codes was evaluated by comparison between the extracted results from the test set and a validation set generated by manual curation.

RESULTS

Among 11,287 reports for development set and 1,107 for the test set describing HLA typing for a single patient, iterative rule generation developed 124 extracting rules and 8 cleaning rules for HLA genotypes. Application of these rules extracted HLA genotypes with 0.892-0.999 precision and 0.795-0.998 recall for the five HLA genes. The precision and recall of the extracting rules for the number of patients in a report were 0.997 and 0.994 and those for the clinical variable extraction were 0.997 and 0.992, respectively. All extracted HLA alleles and serotypes were transformed according to formal HLA nomenclature by the cleaning rules.

CONCLUSION

The rule-based HLA genotype extraction method shows reliable accuracy. We believe that there are significant number of patients who takes profit when this under-used genetic information will be return to them.

Associations of Anti-MHC Class I-related Chain A (MICA) Antibodies with Renal Allograft Outcomes

The association of anti-MHC class I-related chain A (MICA) and kidney allograft rejection has been reported. However, the associations of antibodies specific to donor MICA (dsMICA) and dsMICA levels with allograft outcome have not been elucidated. From November 2009 to June 2017, 125 sera samples from renal transplantation recipients with no HLA antibodies were screened for MICA antibodies. Patients with positive MICA antibody screening results and available residual donor DNA for MICA geno-typing underwent dsMICA analysis. Among these 125 sera samples, 19 were positive for MICA antibodies. dsMICA was positive in 5 out of the 12 analyzed sera samples. Neither MICA antibodies nor dsMICA were associated with acute rejection. However, interstitial fibrosis and tubular atrophy (IFTA) was significantly associated with MICA antibody positivity (OR=3.84, P=0.009). In addition, the MFI value of dsMICA was significantly higher in patients with IFTA II or III than in patients without IFTA II or III (P=0.009). The association of MICA antibodies and dsMICA with high grade IFTA (grade II or III) was suggested. The MICA antibody and dsMICA might be useful indicators of chronic renal damage.

Acceptable Donor-Specific Antibody Levels Before and After Desensitization Therapy in Living Donor Kidney Transplantation

BACKGROUND

Plasmapheresis (PP) is commonly used for desensitization in highly sensitized patients with donor-specific antibodies (DSA) in living donor kidney transplantation. We analyzed the impact of DSA levels before and after desensitization on renal allograft outcome.

METHODS

Twenty-three patients who underwent desensitization with PP, intravenous immunoglobulin (IVIG), and rituximab before kidney transplantation in Seoul National University Hospital from August 2006 to August 2016 were enrolled. The association of median fluorescent intensity (MFI) value of DSA with graft outcome was analyzed.

RESULTS

The frequency of positive HLA class II DSA after desensitization was lower in patients without antibody-mediated rejection (AMR) compared to those with AMR (p = 0.006). The cutoff value of MFI sum of HLA class II DSA after desensitization for predicting AMR was 2,122 with 63% sensitivity and 94% specificity. The frequency of moderate HLA class II DSA (MFI 5,000 - 10,000) after desensitization was significantly higher in patients with graft loss compared to those without graft loss (p = 0.02).

CONCLUSIONS

Weak HLA class II DSA after desensitization including PP, IVIG, and rituximab was related to AMR and moderate levels of HLA class II DSA after desensitization was related to graft loss in living donor kidney transplantation.

GWAS identifying HLA-DPB1 gene variants associated with responsiveness to hepatitis B virus vaccination in Koreans: Independent association of HLA-DPB1*04:02 possessing rs1042169 G - rs9277355 C - rs9277356 A

Recently, HLA class II loci, including HLA-DPB1, have been reported to be associated with interindividual variance in the hepatitis B (HB) vaccine response. In this study, we investigated significant single nucleotide polymorphisms (SNPs) for anti-HBs antibody levels in 6867 healthy Koreans using a genome-wide association study (GWAS). In GWAS, the top 20 SNPs that showed significant association with anti-HBs levels (P < 1.0 × 10^-29 ) all resided in HLA-DPB1. Utilizing PCR sequencing, we verified the relationship of the top 3 most significant SNPs (rs1042169, rs9277355 and rs9277356) from the GWAS and genotypes of HLA-DPB1 with the HB vaccine response in Korean infants who received a scheduled vaccination. The DPB1*04:02 allele has G, C and A nucleotides for the 3SNP sites, and was significantly more frequent in responders than in nonresponders (10.9% vs 1.0%, P_c  = 0.018). DPB1*05:01 was significantly more frequent in nonresponders than in responders (49.0% vs 31.1%, P_c  = 0.018). In multivariate logistic regression, DPB1*04:02 showed a significant association with both vaccine response (P = 0.037, OR = 8.465) and high-titre response (P = 0.027, OR = 9.860). The haplotypes rs1042169 G - rs9277355 C - rs9277356 A showed a significant association with a high-titre response only (P = 0.002, OR = 2.941). In conclusion, DPB1*04:02 possessing rs1042169 G - rs9277355 C - rs9277356 A is an independent predictor of the HB vaccine response in Koreans.

Clinical importance of the updated Oxford classification in allograft IgA nephropathy

With the recent update to the Oxford classification for allograft IgA nephropathy (IgAN), additional investigations on the clinical significance of the updated components are warranted. We performed a retrospective cohort study at two tertiary hospitals. Kidney transplant recipients diagnosed with allograft IgAN were included in the study after additional review by specialized pathologists. We applied the updated Oxford classification and determined the MEST-C scores of the patients. The main study outcome was death-censored graft failure within 10 years after the establishment of allograft IgAN diagnosis and was assessed using the Cox regression analysis. Three hundred thirty-three allograft IgAN patients were reviewed: 100 patients with confirmed native IgAN and 233 patients with other, clinical, or unknown primary causes for end-stage renal disease (ESRD). The updated Oxford classification for allograft IgAN demonstrated prognostic value for graft failure, and patients with multiple MEST-C components had worse outcomes. M, E, S, and C were significantly associated with the prognosis of recurred IgAN and T was the only independent prognostic parameter for allograft IgAN without confirmed native IgAN. Therefore, we suggest reporting MEST-C scores in allograft biopsies and careful interpretation of the results according to the primary cause of ESRD.

Removal of Non-specific Reactions of LABScreen Single Antigen Class II Assay by Fetal Bovine Serum Treatment

Recently, the removal of false reaction from beads 10 (DRB1 ^*04:04), 30 (DRB1 ^*16:01), and 31 (DRB1 ^*16:02) by fetal bovine serum (FBS) treatment in LABScreen Single Antigen Class II Assay was reported. We aimed to confirm the reaction in many cases. Fifty-nine sera showed positivity on at least two among beads 10, 30 and 31 from Nov 2017 to Oct 2018 in Seoul National University Hospital were included. FBS treatment was performed on 59 sera, and Single Antigen Class II Assay was repeated. Among 59 cases, the negative conversion rates of DR16 (57/59, 96.6%), DR4 (37/39, 94.9%), and accompanied other antibodies, e.g.) DP19 (39/45, 86.7%) were very high. The prior use of intravenous immunoglobulin in a non-specific binding group was significantly higher than the sex, age-matched control group (P=0.005).

Maternal lipid profiles vs. fetal growth and cord blood hematopoietic cells: weak associations in healthy Korean newborn-mother pairs

BACKGROUND

We aimed to define the maternal lipid profiles that are associated with fetal growth and cord blood (CB) hematopoietic cells in healthy Korean full-term newborns.

METHODS

A total of 608 fetal-maternal pairs were enrolled; mothers voluntarily donated CB with informed consent. We analyzed birth weight (BW) as a marker of fetal growth, and we examined total nucleated cells (TNCs) and CD34⁺ cell concentrations of CB as markers of hematopoietic progenitor cell (HPC) contents. We also analyzed maternal lipid levels and investigated their associations with BW, TNCs and CD34⁺ cells.

RESULTS

Maternal triglycerides (TG) showed a significant positive association with BW and CD34⁺ cells, and low-density lipoprotein (LDL) showed a negative association with BW and CD34⁺ cells. Though not statistically significant, higher maternal TG showed a tendency toward higher levels of TNCs. Maternal TG was independently and positively correlated with BW, and maternal LDL was independently and negatively correlated with CD34⁺ cells, although the impacts were not as strong, as indicated by small beta coefficients (0.157 and -0.226, respectively).

CONCLUSIONS

We were able to investigate the association of maternal lipid profiles with BW and CB HPCs in healthy Korean newborn-mother pairs in this study. Both BW and the HPC contents showed independent associations with maternal TG and LDL, although the effect of maternal lipid levels on fetal growth and HPCs was not strong in the normal healthy population. Because maternal lipid levels were assessed once in the healthy fetal-maternal pairs, we could not investigate those associations across pregnancy.

Novel susceptibility alleles in HLA region for myositis and myositis specific autoantibodies in Korean patients

OBJECTIVES

HLA genes are a major genetic risk factor for myositis and myositis specific antibodies (MSAs), exhibiting unique HLA backgrounds for myositis in different ethnic groups. This is the first large scale Korean study to genotype the HLA-DRB1 and -DPB1 alleles and to examine their association with myositis and MSAs.

METHODS

HLA-DRB1 and HLA-DPB1 alleles and MSAs were examined in 179 patients with dermatomyositis (DM, n = 129) or polymyositis (PM, n = 50) and healthy controls (n = 800 for HLA-DRB1, n = 548 for HLA-DPB1). Associations between individual HLA alleles and myositis/MSA were examined. Bonferroni correction was applied for multiple testing comparing patients and controls.

RESULTS

A total of 33 HLA-DRB1 and 24 HLA-DPB1 alleles were genotyped in patients and controls. MSAs were found in 67.0% of patients. Anti-MDA5 (26.8%) and anti-aminoacyl-tRNA synthetase antibodies (15.6%) were most common, followed by anti-Mi2 (9.5%) and anti-TIF1γ antibodies (8.9%). HLA-DRB1*12:02 and HLA-DRB1*14:03 were associated with DM and PM, respectively. HLA-DRB1*12:02 was associated with anti-MDA5, HLA-DRB1*08:03 with anti-ARS, HLA-DRB1*14:03 with anti-SRP, and HLA-DRB1*07:01 with anti-Mi2 antibodies. Although HLA-DRB1*13:01 was associated with anti-TIF1γ antibodies, the frequency of HLA-DRB1*13:01 was rare. HLA-DPB1*02:01 was negatively associated with myositis and PM while HLA-DPB1*17:01 was associated with anti-Mi2 positive DM.

CONCLUSIONS

Unique immunogenetic background was observed for Korean patients with myositis. Novel myositis susceptibility alleles, HLA-DRB1*12:02 and HLA-DRB1*14:03, were identified, together with MSA-associated HLA alleles unique to Korean patients with myositis.

Protect to Damage? Institutional work, unintended consequences and institutional dynamics

How does institutional work to uphold an institution unintentionally challenge that institution? To answer this question, I trace institutional work of proponents of change and the norm majority – members of the public who show rectitude vis-à-vis perceived provocation against an established institution, in the context of America’s first bird protection movement. A historical process analysis reveals that institutional work unintentionally compromises institutions because the work can be seen as public conformity to the established institution. A model developed from the findings provides a more refined understanding of unintended consequences in institutional studies.

Association of FOXP3 Single Nucleotide Polymorphisms With Clinical Outcomes After Allogenic Hematopoietic Stem Cell Transplantation

BACKGROUND

Forkhead box P3 (FOXP3) is an important marker of regulatory T cells. FOXP3 polymorphisms are associated with autoimmune diseases, cancers, and allograft outcomes. We examined whether single nucleotide polymorphisms (SNPs) at the FOXP3 locus are associated with clinical outcomes after allogenic hematopoietic stem cell transplantation (HSCT).

METHODS

Five FOXP3 SNPs (rs5902434, rs3761549, rs3761548, rs2232365, and rs2280883) were analyzed by PCR-sequencing of 172 DNA samples from allogenic HSCT patients. We examined the relationship between each SNP and the occurrence of graft-versus-host disease (GVHD), post-HSCT infection, relapse, and patient survival.

RESULTS

Patients with acute GVHD (grades II-IV) showed higher frequencies of the rs3761549 T/T genotype, rs5902434 ATT/ATT genotype, and rs2232365 G/G genotype than did patients without acute GVHD (P=0.017, odds ratio [OR]=5.3; P=0.031, OR=2.4; and P=0.023, OR=2.6, respectively). Multivariate analysis showed that the TT genotype of rs3761549 was an independent risk factor for occurrence of acute GVHD (P=0.032, hazard ratio=5.6). In contrast, the genotype frequencies of rs3761549 T/T, rs5902434 ATT/ATT, and rs2232365 G/G were lower in patients with post-HSCT infection than in patients without infection (P=0.026, P=0.046, and P=0.031, respectively).

CONCLUSIONS

rs3761549, rs5902434, and rs2232365 are associated with an increased risk of acute GVHD and decreased risk of post-HSCT infection.

The Role of the Signal-to-Cutoff Ratio in Automated Anti-HCV Chemiluminescent Immunoassays by Referring to the Nucleic Acid Amplification Test and the Recombinant Immunoblot Assay

Background

Following discontinuation of the recombinant immunoblot assay (RIBA), the only available supplementary test for the detection of hepatitis C virus (HCV) is the nucleic acid amplification test (NAAT). However, the NAAT does not adequately detect past HCV. Consequently, it is hard to distinguish between past HCV infection and biological false positivity with an anti-HCV result alone. We assessed the diagnostic performance of two immunoassays: the ARCHITECT anti-HCV chemiluminescent microparticle immunoassay (CMIA; Abbott Diagnostics, Wiesbaden, Germany) and the Access HCV Ab PLUS chemiluminescent immunoassay (CIA; Bio-Rad, Marnes-la-Coquette, France). We also explored an optimized algorithm to determine the anti-HCV results.

Methods

We tested 126,919 patients and 44,556 individuals who underwent a medical checkup. RIBA and NAAT were conducted for samples that tested anti-HCV-positive using CMIA and CIA. We assessed the optimal signal-to-cutoff (S/CO) ratio in HCV-positive samples.

Results

In total, 1,035 blood samples tested anti-HCV-positive. Of these, RIBA was positive in 512, indeterminate in 160, and negative in 363 samples. One hundred sixty-five samples were NAAT-positive. Diagnostic sensitivity and positive predictive value (PPV) were 96.7% and 52.1%, respectively, for CMIA, and 94.7% and 72.3%, respectively, for CIA. The optimal S/CO ratio was 5.2 for CMIA and 2.6 for CIA at 95% PPV. In total, 286 samples tested positive in CMIA and 444 in CIA, while 443 samples tested positive in both assays.

Conclusions

It is hard to determine anti-HCV positivity based on the S/CO ratio alone. However, this study elucidated the role of the S/CO ratio by using the NAAT and RIBA.

Association of Foxp3 Polymorphism With Allograft Outcome in Kidney Transplantation

Background

Forkhead box P3 (Foxp3) is the most reliable marker for regulatory T cells, which play an important role in maintaining renal allograft tolerance. Recently, Foxp3 polymorphisms have been reported to be associated with graft outcome in kidney transplantation. We analyzed the association of Foxp3 polymorphisms with renal allograft outcome.

Methods

Foxp3 polymorphisms (rs3761548 A/C, rs2280883 C/T, rs5902434 del/ATT, and rs2232365 A/G) were tested by PCR with sequence-specific primers (PCR-SSP) in 231 adult kidney transplantation recipients from 1996-2004 at Seoul National University Hospital.

Results

Patients with the rs3761548 CC genotype showed better graft survival than those with the AC or AA genotype (log rank test, P=0.03). Patients with the rs3761548 CC genotype also showed a lower rate of recurrence of the original glomerular disease than those with the AC or AA genotype (P=0.01). The frequency of acute rejection (AR) in patients with the rs2280883 TT genotype was lower than that in patients with the rs2280883 CT or CC genotype (26.9% vs 53.3%, P=0.038). Patients with the rs2280883 TT genotype also showed better graft survival than those with the CT or CC genotype (P=0.03).

Conclusions

Foxp3 rs3761548 CC and rs2280883 TT genotypes were associated with superior graft outcome of kidney transplantation. Further studies involving a larger number of patients are needed.

Pretransplantation fetal-maternal microchimerism in pediatric liver transplantation from mother

AIM

To investigate the rates of pretransplantation fetal-maternal microchimerism (MC) and its effect on rejection in children receiving maternal liver grafts.

METHODS

DNA or blood samples before liver transplantation (LT) were available in 45 pediatric patients and their mothers. The presence of pretransplantation MC to non-inherited maternal antigens (NIMAs) (NIMA-MC) in the peripheral blood was tested using nested PCR-single-strand conformation polymorphism analysis for the human leukocyte antigen (HLA)-DRB1 alleles. NIMA-MC was successfully evaluated in 26 of the 45 children. Among these 45 pediatric LT recipients, 23 children (51.1%) received transplants from maternal donors and the other 22 from non-maternal donors.

RESULTS

Among these 26 children, pretransplantation NIMA-MC was detected in 23.1% (n = 6), 6.1 (range, 0.8-14) years after birth. Among the children with a maternal donor, the rate of biopsy-proven cellular rejection (BPCR) was 0% in patients with NIMA-MC positivity (0/3) and those with HLA-DR identity with the mother (0/4), but it was 50% in those with NIMA-MC negativity (5/10). Patients with NIMA-MC positivity or HLA-DR identity with the mother showed significantly lower BPCR rate compared with NIMA-MC-negative patients (0% vs 50%, P = 0.04). NIMA-MC-positive patients tended to show lower BPCR rate compared with NIMA-MC-negative patients (P = 0.23).

CONCLUSION

The presence of pretransplantation NIMA-MC or HLA-DR identity with the mother could be associated with BPCR-free survival in pediatric recipients of LT from maternal donors.

Development of Real-time PCR and Melting Curve Analysis for the Rapid Detection of DEL with RHD (c.1222T>C) or RHD (c.1227G>A)

BACKGROUND

DEL, a variant of RhD, is difficult to detect in routine blood bank testing owing to its extremely low levels of D antigen expression. However, DEL is capable of alloimmunizing a patient when transfused into RhDnegative individuals.

METHODS

In this study, we developed real-time PCR and melting curve analysis for the rapid detection of the DEL phenotype.

RESULTS

Of the 325 serologically RhD-negative individuals involved in the study, 56 (17.2%) had melting temperatures distinguishable from complete RHD absence as follows: 53 RHD (c.1227G>A) DEL specimens had a plateau at 54 - 56°C and a peak at 61.95°C, while 3 RHD (c.1222T>C) DEL had a melting temperature of 62.62°C. All DEL results were identical to those obtained by multiplex single-base primer extension reactions.

CONCLUSIONS

The rapid DEL genotyping method developed in this study will be useful for screening DEL in serologically RhD-negative donors and preventing the alloimmunization of RhD-negative individuals by DEL.

Development and validation of a nursing professionalism evaluation model in a career ladder system

BACKGROUND

The clinical ladder system categorizes the degree of nursing professionalism and rewards and is an important human resource tool for managing nursing.

AIM

We developed a model to evaluate nursing professionalism, which determines the clinical ladder system levels, and verified its validity.

METHODS

Data were collected using a clinical competence tool developed in this study, and existing methods such as the nursing professionalism evaluation tool, peer reviews, and face-to-face interviews to evaluate promotions and verify the presented content in a medical institution. Reliability and convergent and discriminant validity of the clinical competence evaluation tool were verified using SmartPLS software. The validity of the model for evaluating overall nursing professionalism was also analyzed.

RESULTS

Clinical competence was determined by five dimensions of nursing practice: scientific, technical, ethical, aesthetic, and existential. The structural model explained 66% of the variance. Clinical competence scales, peer reviews, and face-to-face interviews directly determined nursing professionalism levels.

CONCLUSIONS

The evaluation system can be used for evaluating nurses' professionalism in actual medical institutions from a nursing practice perspective.

IMPLICATIONS FOR NURSING MANAGEMENT

A conceptual framework for establishing a human resources management system for nurses and a tool for evaluating nursing professionalism at medical institutions is provided.

Associations of FoxP3 gene polymorphisms with severe recurrent respiratory papillomatosis in Korean patients

Background

FoxP3 is the most dependable marker for regulatory T cells which play a major role in immune tolerance. Foxp3 gene polymorphisms were associated with various autoimmune diseases and clearance of viral infections. We studied the association of Foxp3 polymorphisms in severe RRP patients.

Methods

A total of 30 Korean severe RRP patients and 195 healthy controls were enrolled. Foxp3 polymorphisms (rs5902434 del/ATT, rs3761548 C/A, rs3761549 C/T, and rs2232365 G/A) were determined by PCR and sequencing.

Results

Genotype frequencies (GF) of rs5902434 ATT/ATT and rs2232365 GG were significantly decreased in female RRP patients than controls (0.0% vs 23.0%, p = 0.039, OR = 9.4 for both).

Conclusions

We showed that Foxp3 polymorphism of rs5902434 and rs2232365 could be an important protective factor in the susceptibility of severe RRP in female Koreans. Further studies on larger number of patients and other ethnic groups are needed to clarify the association.

Poor predictability of QuantiFERON-TB assay in recipients and donors for tuberculosis development after kidney transplantation in an intermediate-TB-burden country

BACKGROUND

Tuberculosis (TB) is a common opportunistic infection after kidney transplantation (KT). The QuantiFERON-TB-Gold In-Tube test (QFT) is widely used for assessing latent TB; however, it is currently unclear whether the pre-KT QFT of the recipient and donor can predict post-KT TB.

METHODS

We retrospectively reviewed patients who received KT between January 2009 and December 2015 at Seoul National University Hospital. The QFT was performed in 458 KT recipients and 239 paired living donors, and 138 KT recipients underwent both the QFT and tuberculin skin test (TST). After excluding 12 patients diagnosed as having clinically latent TB, we evaluated whether the QFT of the recipient and donor was predictive for new-onset active TB after KT.

RESULTS

The QFT was positive in 101 (22.1%) recipients and associated with clinically latent TB before KT (P < 0.05). However, agreement between the TST and QFT was poor (κ = 0.327). Post-KT TB occurred in 1 of 95 recipients with a positive QFT, and 2 cases of TB occurred among 351 patients with a negative or indeterminate QFT. The incidence of TB was 242 cases/100,000 person-years among 446 KT recipients with a median follow-up of 30.2 months. The QFT of recipients could not predict post-KT TB in Poisson regression analysis (relative risk [RR], 1.847; 95% confidence interval [CI], 0.168-20.373; P = 0.616). Of 234 living donor-recipient pairs, the QFT of the recipient (RR, 5.012; 95% CI, 0.301-83.430; P = 0.261) and QFT of the donor (RR, 1.758; 95% CI, 0.106-29.274; P = 0.694) could not predict post-KT TB.

CONCLUSION

The QFT of recipients or living donors pre-KT cannot predict the short-term development of post-KT TB in an intermediate TB-burden country.

Long-Term Quality Control Program Plan for Cord Blood Banks in Korea: A Pilot Study for Cryopreservation Stability

Background

Maintaining the quality of cryopreserved cord blood is crucial. In this pilot study, we describe the results of the internal quality control program for a cord blood bank thus far.

Methods

Donated cord blood units unsuitable for transplantation were selected for internal quality control once a month. One unit of cord blood, aliquoted into 21 capillaries, was cryopreserved and thawed annually to analyze the total nucleated cell count, CD34⁺ cell count, cell viability test, and colony-forming units assay.

Results

No significant differences in the variables (total nucleated cell count, cell viability, CD34⁺ cell count) were observed between samples cryopreserved for one and two years. Upon comparing the variables before cryopreservation and post thawing with the capillaries of one year of storage, cell viability and CD34⁺ cell counts decreased significantly. The use of cord blood samples in capillaries, which can be easily stored for a long period, was similar to the methods used for testing segments attached to the cord blood unit.

Conclusions

The results of this study may be useful for determining the period during which the quality of cryopreserved cord blood units used for transplantation is maintained.

Excluding Anti-cytomegalovirus Immunoglobulin M-Positive Cord Blood Units Has a Minimal Impact on the Korean Public Cord Blood Bank Inventory

Cord blood units (CBUs) for transplantation should be free of communicable disease and must contain a specific amount of total nucleated cells and CD34+ cells. Although posttransplantation cytomegalovirus (CMV) infections are from latent infection in patients, ensuring CMV-free CBUs by performing CMV-specific IgM and nucleic acid amplification testing (NAT) is one of the mandatory procedures for the safety of CBUs. However, the exclusion policies (based on these test results) vary among nations and institutions. We tested 28,000 processed CBUs between May 2006 and June 2014. The cord blood leukocytes from CMV IgM-positive samples were then subjected to NAT. The total nucleated cell and CD34+ cell counts were measured for each CBU, and the results were compared to the CMV IgM and IgG results. The seroprevalence of CMV among pregnant women was 98.1% (18,459/18,818) for IgG and 1.7% (441/25,293) for IgM. The concentration and the total number of CD34+ cells were significantly higher in CBUs from IgM-negative mothers compared to those from IgM-positive mothers (72.4/μl vs. 57.2/μl, respectively, p < 0.0001; 1.45 × 106/unit vs. 1.15 × 106/unit, respectively, p < 0.0001). Among CBUs with positive CMV IgM in their mothers' plasma or cord blood plasma, only 0.58% of the samples (3/517) had a positive NAT. The number of excluded CBUs from inventory due to positive CMV IgM in the cord blood was 54 of 18,326 (0.3%). For inventory purposes, it is appropriate to remove CBUs with positive cord blood CMV IgM findings irrespective of the NAT status as well as positive maternal CMV IgM in South Korea.

Effects of interleukin-4 and interleukin-12B gene polymorphisms on hepatitis B virus vaccination

 Approximately 10% of individuals do not respond to hepatitis B virus (HBV) vaccination, i.e. non-responders (NRs). We aimed to investigate the association of interleukin (IL)-4 and IL-12B gene polymorphisms with responsiveness to the HBV vaccine in Korean infants. Among 300 healthy infants (9-12 month), SNPs for the IL-4 gene (rs2243250, rs2070874, and rs2227284) and for the IL-12B gene (rs3213094 and rs17860508) were compared between subgroups in terms of the response to HBV vaccination. The percentages of NRs (< 10 mIU/mL), low-titer responders (LRs, 10-100 mIU/mL), and high-titer responders (HRs, ≥ 100 mIU/mL) were 20.3%, 37.7% and 42.0%, respectively. No SNPs differed in frequency between NRs and responders or between LRs and HRs. We divided the subjects into two groups according to the time interval from the 3rd dose of HBV vaccination to Ab quantification: > 6 months from the 3rd dose (n = 87) and ≤ 6 months from the 3rd dose (n = 213). In the ≤ 6 month subjects, rs2243250C and rs2227284G were significantly frequent in the lower-titer individuals (NRs + LR) than HRs (40.1 vs. 25.9%, p = 0.014 and 45.1 vs. 33.0%, p = 0.018, respectively), and the rs2243250C and rs2227284G frequencies were significantly different among the three subgroups (13.2 vs. 26.9 vs. 25.9%, p = 0.040 and 15.5 vs. 29.6 vs. 33.0%, p = 0.038, respectively). In conclusion, those results suggest that IL-4 gene polymorphisms may play a role in the response to the HBV vaccine in Korean infants.

Frequency of fetal-maternal microchimerism: an analysis of the HLA-DRB1 gene in cord blood and maternal sample pairs

PURPOSE

We aimed to investigate the frequency of fetal-maternal microchimerism among cord blood (CB) from a Korean population.

MATERIALS AND METHODS

We previously developed a nested polymerase chain reaction-single-strand conformation polymorphism method for microchimerism detection that is highly sensitive (0.01-0.001%) and specific. We used this method to investigate the frequency of fetal-maternal HLA-DRB1 microchimerism among 153 maternal and 152 CB samples.

RESULTS

Among the tested pairs, 41.1% exhibited at least one direction of microchimerism, 32.0% of the mothers possessed fetal microchimerism, and 23.4% of the newborns possessed maternal microchimerism. The overall microchimerism frequency was 28.2%.

CONCLUSIONS

We hypothesize that the different microchimerism frequencies among population and methods are due to differences in detection specificities and subject characteristics. This study provides basic data on fetal-maternal microchimerism that may be useful for future studies on autoimmune disorder and virtual phenotyping in transplantation.

Single nucleotide polymorphisms in the TGF-β1 gene are associated with polycystic ovary syndrome susceptibility and characteristics: a study in Korean women

PURPOSE

Although many hypotheses regarding the pathogenesis of polycystic ovary syndrome (PCOS) have been generated, genetic studies have not identified specific genes that play a role in PCOS etiopathogenesis. This study aimed to investigate the relationship between TGF-β1 gene polymorphism and PCOS in Koreans.

METHOD

A total of 51 Korean women with PCOS and 69 healthy women were enrolled. We analyzed 4 single nucleotide polymorphisms (SNPs) of the TGF-β1 gene (rs11466313, rs1800469, rs2317130, and rs4803457). We also analyzed laboratory measurements, such as free testosterone, glucose, and cholesterol.

RESULTS

The frequencies of rs1800469T allele negativity, rs4803457T allele negativity, the rs1800469CC genotype, and the rs4803457CC genotype showed positive associations with PCOS (P = 0.003, P = 0.027, P = 0.009, and P=0.031, respectively), whereas the haplotypes rs1800469C-rs4803457T and rs1800469T-rs4803457T showed negative associations with PCOS. A strong protective effect of the "rs1800469CT-rs4803457TT" combination (OR = 0.09) and a strong risk effect of "rs1800469CC-rs4803457CC" (OR = 6.23) for PCOS were observed. The rs1800469C/T and rs2317130C/T SNPs exhibited associations with several laboratory measurements with various levels of significance.

CONCLUSION

The results demonstrated an association of TGF-β1 gene polymorphisms with the development and/or characteristics of PCOS in the Korean population.

Association of aplastic anemia and FoxP3 gene polymorphisms in Koreans

OBJECTIVES

Aplastic anemia (AA) is characterized by pancytopenia and bone marrow failure, and most acquired AA is an immune-mediated disorder. Regulatory T cells (T_regs) suppressing autoreactive T cells were decreased in AA patients. FoxP3 is a major regulator for the development and function of T_regs. Polymorphism in FoxP3 was shown to be associated with various autoimmune diseases, however, has not yet been studied in AA. In this study, we examined the association between FoxP3 polymorphisms and AA in Korean patients.

METHODS

The study population consisted of 94 patients diagnosed by bone marrow examination in Seoul National University Hospital (SNUH) during 1997-2012 and 195 healthy controls. FoxP3 polymorphisms (rs5902434 del/ATT, rs3761548 C/A, rs3761549 C/T, rs2232365 A/G) were analyzed by PCR-sequencing method. We analyzed differences of genotype and allele frequencies between patients and controls. We also compared differences of genotype and allele frequencies between responder and non-responder in patients treated with immunosuppressive therapy (IST). For the statistical analysis, the chi-square test and Fisher's exact test were used and P < 0.05 was regarded as statistically significant.

RESULTS

There was no significant difference in the genotype frequencies of FoxP3 polymorphisms between patients and controls. With regards to the allele frequencies, rs3761548 C allele was significantly higher in AA patients than in controls (87.4% vs. 79.7%, P = 0.047). In patients treated with IST, rs3761549 C allele was significantly higher in non-responder patients than in responders (89.6% vs. 66.7%, P = 0.036) and female rs3761549 C/C genotype carriers were associated with greater risk for non-response to IST (84.2% vs. 16.7%, P = 0.006).

CONCLUSION

Polymorphisms in rs3761548 and rs3761549 of FoxP3 in our population were associated with disease susceptibility and response for IST, respectively. This study suggests an association between FoxP3 polymorphisms and AA in Korean patients and will be useful in further understanding the genetic basis of disease susceptibility and response to IST in AA patients.

Performance of LIFECODES HLA-A, -B, and -DRB1 Typing Kits Using Luminex Platform in Koreans

BACKGROUND

Recently, HLA typing using PCR sequence-specific oligonucleotide (SSO) and the Luminex platform has been introduced and widely used in clinical laboratories.

METHODS

We evaluated the performance of LIFECODES HLA-A, -B, and -DRB1 typing kits (Immucor, USA) on 108 samples that had been tested with WAKFlow kits (Wakunaga, Japan) and 54 samples (18 for each A, B, and DRB1 kits) including rare alleles in Koreans (gene frequency < 1.0%) that had been assigned by sequence-based typing (SBT).

RESULTS

LIFECODES 2-digit typing results were 100% concordant with WAKFlow and SBT results. For allelic group assignment, ambiguous results were frequently observed for A*02:01g/*02:07g (n = 47), *02:06g/*02:10g (n = 15), *24:02g/*24:20g (n = 40) and DRB1*04 allelic groups (n = 11). False assignment was observed in 5 cases (2 cases of A*11:02g to A*11:01g; 3 cases of A*26:02g to A*26:01g) due to false reactions of probe 206 and 368, respectively. Additional false reaction did not affect allelic group assignment.

CONCLUSIONS

LIFECODES HLA-A, -B, and -DRB1 typing kits showed good performance in Koreans with correct designation of 2-digit assignment and possible assumption of HLA allelic groups in most cases. They can be properly used for organ transplantation and donor screening of hematopoietic stem cell transplantation in Korea.