1.Considerations of Flow Cytometric Lymphocyte Subset Analysis in Korea Based on a Survey of Current Clinical Laboratory Practice
Mikyoung PARK ; Hyun-Woo CHOI ; Jihyang LIM ; Kyung-Hwa SHIN ; Eun-Jee OH ; Jaewoo SONG ; Kyeong-Hee KIM ; In Hwa JEONG ; Joo-Heon PARK ; Sang-Hyun HWANG ; Eun-Suk KANG
Annals of Laboratory Medicine 2026;46(2):220-225
Flow cytometric lymphocyte subset analysis (FCLSA) is essential for assessing immune status across various diseases and clinical settings. We surveyed current clinical laboratory practices related to FCLSA to establish a baseline reference for future standardization in Korea. Nine university hospitals actively performing FCLSA responded to the 22-question survey, which covered seven categories of laboratory practice. These hospitals used commercial reagent antibody kits from either Beckton Dickinson Biosciences (N = 4) or Beckman Coulter Diagnostics (N = 5). Most hospitals performed daily instrument setup and scheduled maintenance every 2–6 months. Two levels of commercial quality control materials were routinely used each day. Sample and reagent antibody volumes varied across hospitals, even when the same reagent kit was used. Acquired cell counts ranged from 5 × 10 3 to 5 × 10 4 cells, with two hospitals adjusting counts based on the cell type analyzed. Most laboratories reported percentages and general opinions; some additionally reported white blood cell and lymphocyte counts, along with lymphocyte percentages. This is the first comprehensive survey on the clinical laboratory practice of FCLSA in Korea.Standardization of FCLSA should be accelerated to ensure reliable and reproducible results.
2.Risk of malignancies and chemopreventive effect of statin, metformin, and aspirin in Korean patients with ulcerative colitis: a nationwide population-based study
Eun Hye OH ; Ye-Jee KIM ; Minju KIM ; Seung Ha PARK ; Tae Oh KIM ; Sang Hyoung PARK
Intestinal Research 2025;23(2):129-143
Background/Aims:
We investigated the incidences of overall and site-specific malignancies and chemopreventive effects of statin, metformin, and aspirin in patients with ulcerative colitis.
Methods:
We collected data using the Health Insurance Review and Assessment claims database from January 2007 to April 2020.
Results:
The overall malignancy risk among the 35,189 ulcerative colitis patients was similar to that of the general population (standardized incidence ratio, 0.94; 95% confidence interval, 0.88–1.00). In male patients, standardized incidence ratios were high for thyroid cancer and low for stomach cancer, colorectal cancer, liver cancer, and lung cancer. Concurrently, standard incidence ratios were high for liver cancer and central nervous system cancer in female patients. While 122 cases of colorectal cancer occurred in the study patients, the standardized incidence ratio was 0.83 (95% confidence interval, 0.69–0.99). Treatment for ulcerative colitis was not associated with an increased adjusted hazard ratio, while comorbidities increased it for all malignancies. Treatment for ulcerative colitis was associated with an increased adjusted hazard ratio, while comorbidities did not increase it for colorectal cancer. After adjusting for age, sex, comorbidities, and ulcerative colitis treatment, statins showed a dose-dependent chemopreventive effect for all malignancies (P=0.002), while metformin and aspirin did not show any.
Conclusions
In ulcerative colitis patients, standardized incidence ratios for all malignancies and colorectal cancer did not increase. Adjusted hazard ratios for all malignancies increased with comorbidities and those for colorectal cancer with ulcerative colitis treatment. Statins have a dose-dependent chemopreventive effect for all malignancies.
3.Risk of malignancies and chemopreventive effect of statin, metformin, and aspirin in Korean patients with ulcerative colitis: a nationwide population-based study
Eun Hye OH ; Ye-Jee KIM ; Minju KIM ; Seung Ha PARK ; Tae Oh KIM ; Sang Hyoung PARK
Intestinal Research 2025;23(2):129-143
Background/Aims:
We investigated the incidences of overall and site-specific malignancies and chemopreventive effects of statin, metformin, and aspirin in patients with ulcerative colitis.
Methods:
We collected data using the Health Insurance Review and Assessment claims database from January 2007 to April 2020.
Results:
The overall malignancy risk among the 35,189 ulcerative colitis patients was similar to that of the general population (standardized incidence ratio, 0.94; 95% confidence interval, 0.88–1.00). In male patients, standardized incidence ratios were high for thyroid cancer and low for stomach cancer, colorectal cancer, liver cancer, and lung cancer. Concurrently, standard incidence ratios were high for liver cancer and central nervous system cancer in female patients. While 122 cases of colorectal cancer occurred in the study patients, the standardized incidence ratio was 0.83 (95% confidence interval, 0.69–0.99). Treatment for ulcerative colitis was not associated with an increased adjusted hazard ratio, while comorbidities increased it for all malignancies. Treatment for ulcerative colitis was associated with an increased adjusted hazard ratio, while comorbidities did not increase it for colorectal cancer. After adjusting for age, sex, comorbidities, and ulcerative colitis treatment, statins showed a dose-dependent chemopreventive effect for all malignancies (P=0.002), while metformin and aspirin did not show any.
Conclusions
In ulcerative colitis patients, standardized incidence ratios for all malignancies and colorectal cancer did not increase. Adjusted hazard ratios for all malignancies increased with comorbidities and those for colorectal cancer with ulcerative colitis treatment. Statins have a dose-dependent chemopreventive effect for all malignancies.
4.Diagnostic Performance of Eight Blood-based Biomarkers in a Well-characterized Korean Cohort of Preclinical Alzheimer’s Disease
Hyojin CHAE ; Hyejeong KIM ; Yoon-Joo KIM ; HyunYoung JI ; Eun-Jee OH ; Dong Won YANG
Annals of Laboratory Medicine 2025;45(4):428-436
Background:
With the introduction of disease-modifying treatments for Alzheimer’s disease (AD), less invasive and widely accessible screening tests are urgently needed. We assessed eight blood-based biomarkers in a well-defined cohort of preclinical AD, including participants with subjective cognitive decline (SCD) and mild cognitive impairment (MCI).
Methods:
Amyloid beta (Aβ) oligomerization tendency, Aβ42, Aβ40, Aβ42/Aβ40 ratio, phosphorylated tau (p-tau)181, p-tau217, glial fibrillary acidic protein (GFAP), and neurofilament light (Nf-L) were assessed for distinguishing between SCD and MCI, for correlations, and for predicting Aβ positron emission tomography (PET) positivity.
Results:
Plasma p-tau181, p-tau217, and GFAP levels were significantly higher in participants with MCI than in those with SCD (P < 0.05) and in Aβ PET-positive versus Aβ PET-negative participants (P < 0.0001), whereas plasma Aβ42 and Aβ42/40 ratio levels were significantly lower in Aβ PET-positive than in Aβ PET-negative participants (P < 0.001). Logistic regression analysis revealed that plasma Aβ42 and p-tau217 levels predicted Aβ PET positivity with an area under the ROC curve (AUC) of 0.930 (95% confidence interval [CI], 0.848–0.976) in the entire cohort, and p-tau217 alone predicted Aβ PET-positivity with an AUC of 0.887 (95% CI, 0.779–0.954) in the MCI subgroup.
Conclusions
Plasma p-tau217 levels outperform plasma p-tau181 levels in predicting Aβ PET-positivity in participants with preclinical AD. Plasma GFAP levels, along with different ptau isoforms (p-tau181 and p-tau217), effectively differentiate MCI from SCD. The predictive accuracy of blood-based biomarkers for Aβ PET-positivity strongly supports their clinical implementation, particularly with the introduction of disease-modifying therapies.
5.Risk of malignancies and chemopreventive effect of statin, metformin, and aspirin in Korean patients with ulcerative colitis: a nationwide population-based study
Eun Hye OH ; Ye-Jee KIM ; Minju KIM ; Seung Ha PARK ; Tae Oh KIM ; Sang Hyoung PARK
Intestinal Research 2025;23(2):129-143
Background/Aims:
We investigated the incidences of overall and site-specific malignancies and chemopreventive effects of statin, metformin, and aspirin in patients with ulcerative colitis.
Methods:
We collected data using the Health Insurance Review and Assessment claims database from January 2007 to April 2020.
Results:
The overall malignancy risk among the 35,189 ulcerative colitis patients was similar to that of the general population (standardized incidence ratio, 0.94; 95% confidence interval, 0.88–1.00). In male patients, standardized incidence ratios were high for thyroid cancer and low for stomach cancer, colorectal cancer, liver cancer, and lung cancer. Concurrently, standard incidence ratios were high for liver cancer and central nervous system cancer in female patients. While 122 cases of colorectal cancer occurred in the study patients, the standardized incidence ratio was 0.83 (95% confidence interval, 0.69–0.99). Treatment for ulcerative colitis was not associated with an increased adjusted hazard ratio, while comorbidities increased it for all malignancies. Treatment for ulcerative colitis was associated with an increased adjusted hazard ratio, while comorbidities did not increase it for colorectal cancer. After adjusting for age, sex, comorbidities, and ulcerative colitis treatment, statins showed a dose-dependent chemopreventive effect for all malignancies (P=0.002), while metformin and aspirin did not show any.
Conclusions
In ulcerative colitis patients, standardized incidence ratios for all malignancies and colorectal cancer did not increase. Adjusted hazard ratios for all malignancies increased with comorbidities and those for colorectal cancer with ulcerative colitis treatment. Statins have a dose-dependent chemopreventive effect for all malignancies.
6.Single-cell RNA sequencing revealed the role of the Th17 pathway in the development of anti- human leukocyte antigen antibodies in a highly sensitized mouse model
Hanbi LEE ; Yoo-Jin SHIN ; Xianying FANG ; Sheng CUI ; Sun Woo LIM ; Seon-Yeong LEE ; Sang Hun EUM ; Ji-Won MIN ; Chang-Won HONG ; Hae-Ock LEE ; Mi-La CHO ; Eun-Jee OH ; Chul Woo YANG ; Byung Ha CHUNG
Kidney Research and Clinical Practice 2025;44(6):960-973
Background:
The aim of this study is to investigate the specific pathway involved in human leukocyte antigen (HLA) sensitization using single-cell RNA-sequencing analysis and an allo-sensitized mouse model developed with an HLA.A2 transgenic mouse.
Methods:
For sensitization, wild-type C57BL/6 mouse received two skin grafts from C57BL/6-Tg(HLA-A2.1)1Enge/J mouse (allogeneic mouse, ALLO). For syngeneic control (SYN), skin grafts were transferred from C57BL/6 to C57BL/6. We performed single-cell RNA-sequencing analysis on splenocytes isolated from ALLO and SYN and compared the gene expression between them.
Results:
We generated 9,190 and 8,890 single-cell transcriptomes from ALLO and SYN, respectively. Five major cell types (B cells, T cells, natural killer cells, macrophages, and neutrophils) and their transcriptome data were annotated according to the representative differentially expressed genes of each cell cluster. The percentage of B cells was higher in ALLO than it was in SYN. Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that the highly expressed genes in the B cells from ALLO were mainly associated with antigen processing and presentation pathways, allograft rejection, and the Th17 cell differentiation pathway. Upregulated genes in the T cells of ALLO were involved in the interleukin (IL)-17 signaling pathway. The ratio of Th17 cluster and Treg cluster was increased in the ALLO. On flow cytometry, the percentage of Th17 (IL-17+/CD4+ T) cells was higher and regulatory T cells (FOXP3+/CD4+ T) was lower in the ALLO compared to those in the SYN.
Conclusion
Our results indicate that not only the B cell lineage but also the Th17 cells and their cytokine (IL-17) are involved in the sensitization to HLA.
8.Current Status of Flow Cytometric Immunophenotyping of Hematolymphoid Neoplasms in Korea
Mikyoung PARK ; Jihyang LIM ; Ari AHN ; Eun-Jee OH ; Jaewoo SONG ; Kyeong-Hee KIM ; Jin-Yeong HAN ; Hyun-Woo CHOI ; Joo-Heon PARK ; Kyung-Hwa SHIN ; Hyerim KIM ; Miyoung KIM ; Sang-Hyun HWANG ; Hyun-Young KIM ; Duck CHO ; Eun-Suk KANG
Annals of Laboratory Medicine 2024;44(3):222-234
Background:
Flow cytometric immunophenotyping of hematolymphoid neoplasms (FCIHLN) is essential for diagnosis, classification, and minimal residual disease (MRD) monitoring. FCI-HLN is typically performed using in-house protocols, raising the need for standardization. Therefore, we surveyed the current status of FCI-HLN in Korea to obtain fundamental data for quality improvement and standardization.
Methods:
Eight university hospitals actively conducting FCI-HLN participated in our survey.We analyzed responses to a questionnaire that included inquiries regarding test items, reagent antibodies (RAs), fluorophores, sample amounts (SAs), reagent antibody amounts (RAAs), acquisition cell number (ACN), isotype control (IC) usage, positiveegative criteria, and reporting.
Results:
Most hospitals used acute HLN, chronic HLN, plasma cell neoplasm (PCN), and MRD panels. The numbers of RAs were heterogeneous, with a maximum of 32, 26, 12, 14, and 10 antibodies used for acute HLN, chronic HLN, PCN, ALL-MRD, and multiple myeloma-MRD, respectively. The number of fluorophores ranged from 4 to 10. RAs, SAs, RAAs, and ACN were diverse. Most hospitals used a positive criterion of 20%, whereas one used 10% for acute and chronic HLN panels. Five hospitals used ICs for the negative criterion. Positiveegative assignments, percentages, and general opinions were commonly reported. In MRD reporting, the limit of detection and lower limit of quantification were included.
Conclusions
This is the first comprehensive study on the current status of FCI-HLN in Korea, confirming the high heterogeneity and complexity of FCI-HLN practices. Standardization of FCI-HLN is urgently needed. The findings provide a reference for establishing standard FCI-HLN guidelines.
9.Implementation of Pharmaceutical Care Services During the COVID-19 Pandemic Worldwide
So Yeon LEE ; Seunghyun CHEON ; Hye Won PARK ; Sang Hyeon OH ; Jee-Eun CHUNG ; Sook Hee AN
Korean Journal of Clinical Pharmacy 2024;34(4):242-251
Background:
This study sought to research the implementation of pharmaceutical care services and review the pharmaceutical care services used for coronavirus disease 2019 (COVID-19) prevention, diagnosis, therapy, and vaccination during the COVID-19 pandemic.
Methods:
All articles reporting pharmacists’ implementation of pharmaceutical care services during the COVID-19 pandemic were comprehensively searched in PubMed/Medline, Embase, and the Cochrane Library databases up toJuly 7, 2021, then included in this study. Twenty-four items of pharmaceutical care services were classified into the following 5categories: patient evaluation and monitoring, clinical decision support, compounding/dispensing/administration, patient consultation and education, and drug-related policy research and development.
Results:
A total of 674 articles from 100 countrieswere included, with the United States of America being the most frequently studied country. Across the 5 classified categories,compounding/dispensing/administration was most frequently examined (28.9%), followed by patient consultation and education (25.2%). Among the 24 items of pharmaceutical care services, medicine supply management was most frequently reported on (11.4%), followed by patient consultations (11.0%). The primary implemented pharmaceutical care services for COVID-19 prevention, diagnosis, therapy, and vaccination were public health education, COVID-19 testing services, medicine supply management, and vaccination, respectively.
Conclusion
Pharmacists have implemented diverse pharmaceutical care services for COVID-19 prevention, diagnosis, therapy, and vaccination globally. Further studies should be conducted to determine the correlation between the characteristics of healthcare accessibility in a country and the implemented pharmaceutical care services for COVID-19.
10.Implementation of Pharmaceutical Care Services During the COVID-19 Pandemic Worldwide
So Yeon LEE ; Seunghyun CHEON ; Hye Won PARK ; Sang Hyeon OH ; Jee-Eun CHUNG ; Sook Hee AN
Korean Journal of Clinical Pharmacy 2024;34(4):242-251
Background:
This study sought to research the implementation of pharmaceutical care services and review the pharmaceutical care services used for coronavirus disease 2019 (COVID-19) prevention, diagnosis, therapy, and vaccination during the COVID-19 pandemic.
Methods:
All articles reporting pharmacists’ implementation of pharmaceutical care services during the COVID-19 pandemic were comprehensively searched in PubMed/Medline, Embase, and the Cochrane Library databases up toJuly 7, 2021, then included in this study. Twenty-four items of pharmaceutical care services were classified into the following 5categories: patient evaluation and monitoring, clinical decision support, compounding/dispensing/administration, patient consultation and education, and drug-related policy research and development.
Results:
A total of 674 articles from 100 countrieswere included, with the United States of America being the most frequently studied country. Across the 5 classified categories,compounding/dispensing/administration was most frequently examined (28.9%), followed by patient consultation and education (25.2%). Among the 24 items of pharmaceutical care services, medicine supply management was most frequently reported on (11.4%), followed by patient consultations (11.0%). The primary implemented pharmaceutical care services for COVID-19 prevention, diagnosis, therapy, and vaccination were public health education, COVID-19 testing services, medicine supply management, and vaccination, respectively.
Conclusion
Pharmacists have implemented diverse pharmaceutical care services for COVID-19 prevention, diagnosis, therapy, and vaccination globally. Further studies should be conducted to determine the correlation between the characteristics of healthcare accessibility in a country and the implemented pharmaceutical care services for COVID-19.

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