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.

Natural killer (NK) cells play critical roles in immune surveillance and homeostasis maintenance through cytotoxicity and cytokine release. The ability of NK cells to eliminate target cells without the need for prior antigen recognition or antibody involvement has drawn considerable attention for translational and clinical applications. As clinical applications continue to broaden, interest in NK cell assays has been growing markedly. This review provides an in-depth discussion of current clinical applications of NK cell assays, including NK cell phenotype, frequency, and functional activity assessments. This review further highlights the diagnostic potential of these assays in terms of hemophagocytic lymphohistiocytosis and potential NK cell biomarker candidates in diverse pathological contexts, such as cancer, infection, autoimmune diseases, and other diseases. By integrating clinical insights with technological advancements, NK cell assays can serve as valuable tools for disease diagnosis, prognosis, and therapeutic monitoring.

This report provides a summary of the 2024 survey results on the external quality assessment (EQA) scheme for the general transfusion medicine test and the general transfusion antibody test programs in Korea. Proficiency testing materials were prepared at the Asan Medical Center for bi-annual distribution to participating laboratories. The accuracy rates and number of participating laboratories for the bi-annual EQAs were: ABO typing, 99.6%–99.9% (n=944, n=945); RhD typing, 99.9%–100.0% (n=929, n=930);crossmatching, 95.0%–99.2% (n=825, n=825); unexpected antibody scre ening, 99.5%–100.0% (n=363, n=367); direct antiglobulin test (DAT) using a polyspecific reagent, 99.3%–100.0% (n=296, n=299); DAT using an antiimmunoglobulin G monospecific reagent, 100.0% (n=74, n=72); and DAT using an anti-C3d monospecific reagent, 98.6%–100.0% (n=72, n=71). The 2024 EQA scheme for the transfusion medicine program has improved and maintained the standards of the participating laboratories.

This report provides a summary of the 2024 survey results on the external quality assessment (EQA) scheme for the general transfusion medicine test and the general transfusion antibody test programs in Korea. Proficiency testing materials were prepared at the Asan Medical Center for bi-annual distribution to participating laboratories. The accuracy rates and number of participating laboratories for the bi-annual EQAs were: ABO typing, 99.6%–99.9% (n=944, n=945); RhD typing, 99.9%–100.0% (n=929, n=930);crossmatching, 95.0%–99.2% (n=825, n=825); unexpected antibody scre ening, 99.5%–100.0% (n=363, n=367); direct antiglobulin test (DAT) using a polyspecific reagent, 99.3%–100.0% (n=296, n=299); DAT using an antiimmunoglobulin G monospecific reagent, 100.0% (n=74, n=72); and DAT using an anti-C3d monospecific reagent, 98.6%–100.0% (n=72, n=71). The 2024 EQA scheme for the transfusion medicine program has improved and maintained the standards of the participating laboratories.

This report provides a summary of the 2024 survey results on the external quality assessment (EQA) scheme for the general transfusion medicine test and the general transfusion antibody test programs in Korea. Proficiency testing materials were prepared at the Asan Medical Center for bi-annual distribution to participating laboratories. The accuracy rates and number of participating laboratories for the bi-annual EQAs were: ABO typing, 99.6%–99.9% (n=944, n=945); RhD typing, 99.9%–100.0% (n=929, n=930);crossmatching, 95.0%–99.2% (n=825, n=825); unexpected antibody scre ening, 99.5%–100.0% (n=363, n=367); direct antiglobulin test (DAT) using a polyspecific reagent, 99.3%–100.0% (n=296, n=299); DAT using an antiimmunoglobulin G monospecific reagent, 100.0% (n=74, n=72); and DAT using an anti-C3d monospecific reagent, 98.6%–100.0% (n=72, n=71). The 2024 EQA scheme for the transfusion medicine program has improved and maintained the standards of the participating laboratories.

This report provides a summary of the 2024 survey results on the external quality assessment (EQA) scheme for the general transfusion medicine test and the general transfusion antibody test programs in Korea. Proficiency testing materials were prepared at the Asan Medical Center for bi-annual distribution to participating laboratories. The accuracy rates and number of participating laboratories for the bi-annual EQAs were: ABO typing, 99.6%–99.9% (n=944, n=945); RhD typing, 99.9%–100.0% (n=929, n=930);crossmatching, 95.0%–99.2% (n=825, n=825); unexpected antibody scre ening, 99.5%–100.0% (n=363, n=367); direct antiglobulin test (DAT) using a polyspecific reagent, 99.3%–100.0% (n=296, n=299); DAT using an antiimmunoglobulin G monospecific reagent, 100.0% (n=74, n=72); and DAT using an anti-C3d monospecific reagent, 98.6%–100.0% (n=72, n=71). The 2024 EQA scheme for the transfusion medicine program has improved and maintained the standards of the participating laboratories.

This report provides a summary of the 2024 survey results on the external quality assessment (EQA) scheme for the general transfusion medicine test and the general transfusion antibody test programs in Korea. Proficiency testing materials were prepared at the Asan Medical Center for bi-annual distribution to participating laboratories. The accuracy rates and number of participating laboratories for the bi-annual EQAs were: ABO typing, 99.6%–99.9% (n=944, n=945); RhD typing, 99.9%–100.0% (n=929, n=930);crossmatching, 95.0%–99.2% (n=825, n=825); unexpected antibody scre ening, 99.5%–100.0% (n=363, n=367); direct antiglobulin test (DAT) using a polyspecific reagent, 99.3%–100.0% (n=296, n=299); DAT using an antiimmunoglobulin G monospecific reagent, 100.0% (n=74, n=72); and DAT using an anti-C3d monospecific reagent, 98.6%–100.0% (n=72, n=71). The 2024 EQA scheme for the transfusion medicine program has improved and maintained the standards of the participating laboratories.

Incidence of depression increases in patients with end-stage kidney disease (ESKD). We evaluated the association between depression and mortality among older patients with ESKD, which has not been studied previously. Methods: This nationwide prospective cohort study included 487 patients with ESKD aged >65 years, who were categorized into minimal, mild-to-moderate, and severe depression groups based on their Beck Depression Inventory-II (BDI-II) scores. Predisposing factors for high BDI-II scores and the association between the scores and survival were analyzed. Results: The severe depression group showed a higher modified Charlson comorbidity index value and lower serum albumin, phosphate, and uric acid levels than the other depression groups. The Kaplan-Meier curve revealed a significantly lower survival in the severe depression group than in the minimal and mild-to-moderate depression groups (p = 0.011). Multivariate Cox regression analysis confirmed that severe depression was an independent risk factor for mortality in the study cohort (hazard ratio, 1.39; 95% confidence interval, 1.01–1.91; p = 0.041). Additionally, BDI-II scores were associated with modified Charlson comorbidity index (p = 0.009) and serum albumin level (p = 0.004) in multivariate linear regression. Among the three depressive symptoms, higher somatic symptom scores were associated with increased mortality. Conclusion: Severe depression among older patients with ESKD increases mortality compared with minimal or mild-to-moderate depression, and patients with concomitant somatic symptoms require careful management of their comorbidities and nutritional status.

Meningiomas are common intracranial tumors; however, reports on extracranial cutaneous meningiomas are exceedingly rare. A 77-year-old woman visited our hospital with an asymptomatic child fist-sized mass on the scalp.Biopsy results indicated nuclear atypia and mitoses of sarcomatous cells. Brain magnetic resonance imaging revealed a subgaleal mass with strong enhancement. Suspecting sarcoma, wide excision was performed jointly by the departments of plastic surgery and neurosurgery, during which no evidence of cranial invasion was noted. In the surgical specimen, numerous mitoses of sarcomatous cells and poorly formed nests of epithelioid cells were observed. This led to the diagnosis of anaplastic meningioma without intracranial origin. Subsequently, the patient received adjuvant radiotherapy and is currently under close follow-up. Anaplastic meningioma is rare, but early diagnosis is important as it enables timely and appropriate treatment, thus, improving survival rates. Dermatologists should remain vigilant as meningiomas can manifest as cutaneous scalp nodules, and their accurate diagnosis can profoundly impact prognosis.

A 54-year-old man presented to our outpatient clinic with generalized pruritic millet-sized vesicles, pustules, and crusts on the whole body over the past 10 years, which were more dominant in the lower extremities. Due to the difficulty in diagnosis, a series of histopathologic examinations were conducted during the treatment course, and the findings were similar: subcorneal pustules with neutrophils, superficial perivascular and dermal infiltration of lymphocytes, neutrophils, and eosinophils, with no sign of acantholysis. The patient was treated with cyclosporine, prednisolone, doxycycline, colchicine, sulfasalazine, and acitretin; however, his condition did not improve. After showing a dramatic improvement with dapsone, he was finally diagnosed with subcorneal pustular dermatosis (SPD).Various medications commonly used in inflammatory and immunobullous skin diseases were tried but failed to improve the condition; the patient showed a dramatic response only to dapsone. Due to its rarity, careful attention and repeated biopsies are required for diagnosing SPD.