Background: Cancer cell line-derived feeder cells enhance natural killer (NK) cell expansion; however, concerns regarding viable residual feeder cells in the final product limit their use. Evidence supporting the safety of NK-sensitive K562-based feeders, even when irradiated, is scarce. We optimized an NK cell expansion protocol using genetically engineered K562-mbIL-18/-21 (GE-K562) feeder cells and clinical-grade media and confirmed the absence of residual feeder cells. Methods: NK cell expansion efficiency was compared between feeder-free and feederbased systems using CTS NK-Xpander Medium. To achieve optimal NK expansion, various peripheral blood mononuclear cell (PBMC)-to-feeder ratios and re-stimulation frequencies were tested over 21 days. Flow cytometry and BCR::ABL1 quantitative reverse transcription PCR (RT-qPCR) were used to confirm the absence of feeder cells in the final NK cell product. Results: Feeder-based systems showed superior NK cell fold expansion compared with that of feeder-free systems. Among feeder-based conditions, NK cells expanded 5,224-fold at a 2:1 PBMC-to-feeder ratio after 3 weeks, relative to 1,450-fold at a 6:1 ratio (P < 0.05).Re-stimulation on days 7 and 14 further increased expansion up to 261,457-fold. Irradiated feeder cells showed no proliferation and were eliminated within 3–6 days. On day 21, flow cytometry and BCR::ABL1 RT-qPCR results confirmed the absence of residual feeder cells. Conclusions Our optimized NK cell expansion protocol using irradiated GE-K562 feeder cells and clinical-grade media offers a safe and scalable approach to generating large numbers of NK cells, supporting its potential use in clinical immunotherapy applications.

Purpose: Forming a patient safety culture is the first step in addressing patient safety issues. This study therefore examines the patient safety culture among healthcare professionals in South Korea. It also identifies the factors influencing patient safety culture and related activities. Methods: Among the survey studies conducted in South Korea, we reviewed those that measured patient safety culture using the Korean version of the Hospital Survey on Patient Safety Culture 1.0. We identified the level of patient safety culture, the relationship between patient safety culture and patient safety activities, and the factors affecting patient safety culture. Results: A total of 640 studies were identified through searches of seven domestic and international databases, with 58 included in the analysis. Studies targeting nurses accounted for 96.6%. The general characteristics of patient safety culture included length of service, age, working hours, department of work, hospital size, conflict occurrence, unreported incidents, and subjective safety management evaluations. A statistically significant correlation between patient safety culture and patient safety activities was confirmed in 84.5% of studies. Patient safety culture was the most frequently reported factor influencing patient safety activities. Conclusion Strategies to enhance patient safety culture can promote patient safety activities in South Korean healthcare institutions. Considering organizational and organizational members characteristics when devising these strategies can enhance their effectiveness.

Purpose: Forming a patient safety culture is the first step in addressing patient safety issues. This study therefore examines the patient safety culture among healthcare professionals in South Korea. It also identifies the factors influencing patient safety culture and related activities. Methods: Among the survey studies conducted in South Korea, we reviewed those that measured patient safety culture using the Korean version of the Hospital Survey on Patient Safety Culture 1.0. We identified the level of patient safety culture, the relationship between patient safety culture and patient safety activities, and the factors affecting patient safety culture. Results: A total of 640 studies were identified through searches of seven domestic and international databases, with 58 included in the analysis. Studies targeting nurses accounted for 96.6%. The general characteristics of patient safety culture included length of service, age, working hours, department of work, hospital size, conflict occurrence, unreported incidents, and subjective safety management evaluations. A statistically significant correlation between patient safety culture and patient safety activities was confirmed in 84.5% of studies. Patient safety culture was the most frequently reported factor influencing patient safety activities. Conclusion Strategies to enhance patient safety culture can promote patient safety activities in South Korean healthcare institutions. Considering organizational and organizational members characteristics when devising these strategies can enhance their effectiveness.

Purpose: Forming a patient safety culture is the first step in addressing patient safety issues. This study therefore examines the patient safety culture among healthcare professionals in South Korea. It also identifies the factors influencing patient safety culture and related activities. Methods: Among the survey studies conducted in South Korea, we reviewed those that measured patient safety culture using the Korean version of the Hospital Survey on Patient Safety Culture 1.0. We identified the level of patient safety culture, the relationship between patient safety culture and patient safety activities, and the factors affecting patient safety culture. Results: A total of 640 studies were identified through searches of seven domestic and international databases, with 58 included in the analysis. Studies targeting nurses accounted for 96.6%. The general characteristics of patient safety culture included length of service, age, working hours, department of work, hospital size, conflict occurrence, unreported incidents, and subjective safety management evaluations. A statistically significant correlation between patient safety culture and patient safety activities was confirmed in 84.5% of studies. Patient safety culture was the most frequently reported factor influencing patient safety activities. Conclusion Strategies to enhance patient safety culture can promote patient safety activities in South Korean healthcare institutions. Considering organizational and organizational members characteristics when devising these strategies can enhance their effectiveness.

Background: Daratumumab is a human monoclonal antibody targeting CD38 used widely in various related conditions. Caution is advised when interpreting the pretransfusion tests in daratumumab-treated patients because they may show nonspecific reactions with red blood cells. This paper provides experimental evidence for the false-positive interference phenomena induced by daratumumab in in-vitro and ex-vivo experiments and experimental support for resolving it using dithiothreitol (DTT). Methods: Fifteen crossmatching pairs, four cardiac amyloidosis (CA) patients treated with daratumumab, and three healthy individuals were included. The flow cytometry crossmatch (FCMXM) was conducted with negatively selected T and B cells. After spiking the sera with 500 μg/mL daratumumab, the T and B cells were treated with DTT. The prospective FCMXM was conducted with the sera of CA patients treated with daratumumab. The CD38 expression levels in T, B, and NK cells were measured without and with a DTT or pronase treatment. Results: Five hundred μg/mL of daratumumab spiking was sufficient to elicit a false positive effect in T cell FCMXM. In particular, the administration of 0.1 M DTT efficiently resolved the induced false positivity in flow cytometry. Moreover, DTT caused a decrease in the CD38 expression levels in T, B, and NK cells. Conclusion A typical therapeutic dose of daratumumab causes false-positive FCMXM, which was effectively addressed by a DTT treatment. Therefore, information about the patient’s medical condition and the use of immunotherapeutics, such as daratumumab, is needed, given its impact on diverse CD38-expressing cells.

Objectives: The household secondary attack rate (SAR) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important indicator for community transmission. This study aimed to characterize transmission by comparing household SARs and identifying risk factors during the periods of Delta and Omicron variant predominance in Republic of Korea. Methods: We defined the period of Delta variant predominance (Delta period) as July 25, 2021 to January 15, 2022, and the period of Omicron variant predominance (Omicron period) as February 7 to September 3, 2022. The number of index cases included was 214,229 for the Delta period and 5,521,393 for the Omicron period. To identify the household SARs and risk factors for each period, logistic regression was performed to determine the adjusted odds ratio (aOR). Results: The SAR was 35.2% for the Delta period and 43.1% for the Omicron period. The aOR of infection was higher in 2 groups, those aged 0 to 18 years and ≥75 years, compared to those aged 19 to 49 years. Unvaccinated individuals (vs. vaccinated individuals) and individuals experiencing initial infection (vs. individuals experiencing a second or third infection) had an increased risk of infection with SARS-CoV-2. Conclusion: This study analyzed the household SARs and risk factors. We hope that the results can help develop age-specific immunization plans and responses to reduce the SAR in preparation for emerging infectious diseases or potential new variants of SARS-CoV-2.