Common variable immunodeficiency (CVID) is a heterogeneous primary immunodeficiency characterized by reduced levels of immunoglobulin (Ig)G, with or without IgA and/or IgM deficiency, and hypogammaglobulinemia. Clinical manifestations are diverse, ranging from recurrent infections to autoimmune and allergic diseases. While CVID has been rarely reported in the Korean population, particularly in adults, we report 2 adult cases of CVID comorbid with asthma and Behcet’s disease. The first case of a 53-year-old with severe allergic asthma and chronic rhinosinusitis experienced recurrent respiratory infections, stomatitis, and cystitis requiring frequent antibiotic treatment. Laboratory findings indicated a T2-high asthma phenotype, with elevated serum total IgE specific IgE to dog hair and fractional exhaled nitric oxide. Immunological evaluation revealed decreased serum IgG (including IgG1 and IgG2), along with hypogammaglobulinemia. She had been treated with regular anti-IgE antibody therapy and intravenous immunoglobulin replacement therapy (IVIGRT). The second case of a 38-year-old with Behçet’s disease and uveitis had bronchial asthma and rhinitis that were exacerbated by recurrent infections despite standard asthma therapy. Laboratory findings revealed a T2-low phenotype and a marked reduction in serum IgG (including IgG1, IgG2, and IgG4), and hypogammaglobulinemia, consistent with CVID.IVIGRT effectively reduced asthma exacerbations and infection episodes in both cases. These cases highlight the clinical heterogeneity of CVID and its potential overlap with allergic and autoimmune diseases. Immunological evaluation of underlying immunodeficiency should be considered in adult patients with asthma who present with frequent exacerbations and recurrent infections. Early diagnosis and IVIGRT can prevent complications and improve outcomes.

Purpose: We compared short-term clinical outcomes after cataract surgery with implantation of a novel refractive extended depth-of-focus TECNIS PureSee intraocular lens (IOL) between patients with stage 1 epiretinal membrane (ERM)—characterized by a thin membrane over the macula with preserved foveal depression―and those with a normal retina. Methods: This retrospective study included 60 eyes of 60 patients who underwent cataract surgery with implantation of the TECNIS PureSee IOL between January 2024 and January 2025: 30 eyes with stage 1 ERM and 30 eyes with a normal retina. Preoperative characteristics, including age, sex distribution, cataract severity, corrected distance visual acuity (CDVA), and higher-order aberrations, were compared between groups, as were IOL power and target refraction. Postoperative outcomes at 1 month―including CDVA, uncorrected distance, intermediate, and near visual acuity, ocular aberrations, and contrast sensitivity―were evaluated. Results: There were no significant differences in preoperative characteristics, such as age, sex distribution, cataract grade, CDVA, higher-order aberrations, IOL power, or target refraction between the two groups. At 1 month postoperatively, CDVA, uncorrected distance, intermediate, and near visual acuity, higher-order aberrations, and contrast sensitivity exhibited no significant differences between groups. Conclusions In this short-term analysis, the PureSee IOL demonstrated comparable efficacy and safety in cataract patients with stage 1 ERM to those with a normal retina.

Objectives: In alignment with the World Health Organization’s goal of eliminating hepatitis C, this study assessed the current treatment status and reasons for non-treatment among patients with hepatitis C in Jeonbuk State, Republic of Korea, to inform strategies for improving care engagement. Methods: Among 311 individuals diagnosed with hepatitis C and reported through the NationalNotifiable Infectious Disease Surveillance system between January 2023 and June 2024, 208 patients were surveyed after excluding those who had died or could not be contacted.Statistical analyses included the chi-square test, the Cochran-Armitage test for trend, and logistic regression. Results: Overall, 116 participants (55.8%) reported having received antiviral therapy. Among the 92 untreated individuals, the most common reason for non-treatment was the absence of symptoms (n = 23; 25.0%), followed by the burden of drug costs (n = 21; 22.8%). Conclusion These findings highlight suboptimal treatment uptake and key barriers that may hinder progress toward hepatitis C elimination. Expanding screening and strengthening linkage-to-care strategies, while addressing financial barriers, will be essential to achievingnational elimination targets.

Objectives: In May 2025, clusters of salmonellosis were identified in 7 cities in the Republic of Korea, all associated with consumption of identical bakery products. This investigation aimed to characterize the outbreak, identify potential contributing factors, and inform strategies for preventing similar multi-facility foodborne outbreaks. Methods: A case series study was conducted among individuals who consumed Manufacturer H’s Product I and Product II on May 15–16, 2025 at 7 facilities (n = 1,235). Clinical specimens from symptomatic individuals, retained food samples, and environmental samples were collected and tested. Food-exposure histories were assessed, and active case finding was implemented across all supplied facilities. Traceback investigations were conducted at the manufacturer, distributor, and egg farms. Human and food isolates underwent pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS). Results: A total of 323 cases met the outbreak case definition (attack rate, 26.2%), of which 48 were laboratory-confirmed. Salmonella Enteritidis was isolated from both clinical specimens and retained bakery products. PFGE patterns were indistinguishable between human and food isolates, and WGS demonstrated high genetic relatedness. These findings confirmed a common-source outbreak linked to the implicated bakery products. Conclusion This outbreak underscores the value of integrating epidemiological investigation, active case finding, and molecular typing to identify common food vehicles in outbreaks involving widely distributed manufactured foods. Coordinated collaboration between public health and food safety authorities is essential for the effective detection, response, and prevention of multi-facility foodborne outbreaks.

Background/Aims: This study investigated the clinical efficacy of low-dose mepolizumab (100 mg) in controlling severe eosinophilic asthma, aiming to induce eosinophilic granulomatosis with polyangiitis (EGPA) remission and reduce systemic steroid usage. Additionally, we constructed a basic frame for our longitudinal EGPA cohort by collecting serial blood samples before, during, and after mepolizumab treatment in EGPA patients. Methods: We conducted a 2-year prospective observational cohort study in patients with uncontrolled severe eosinophilic asthma and refractory EGPA who used systemic steroids (≥ 7.5 mg/day of prednisolone) or other immunosuppressant drugs for at least 6 months. All patients were treated with 100 mg of mepolizumab every 4 weeks for 1 year to control severe eosinophilic asthma and then were followed for an additional 1 year to monitor their disease course. We analyzed total systemic steroid use and EGPA remission/relapse during the study period. Results: Three EGPA patients were included in this study and completed 16 study visits over a 2-year period. After 1 year of treatment with mepolizumab (100 mg monthly), all 3 patients were able to reduce their maintenance dose of systemic steroids, with 2 patients completely discontinuing use. These 2 patients achieved EGPA remission during mepolizumab treatment, and their remission status remained stable for 1 year after they stopped receiving the medication. Conclusions Low-dose mepolizumab treatment demonstrated clinical efficacy in reducing the maintenance dose of systemic steroids required for severe refractory EGPA. While not all patients achieved EGPA remission with low-dose mepolizumab, some did, and their remission persisted even after treatment discontinuation.

Background/Aims: Patients with atrial fibrillation (AF) and end-stage kidney disease (ESKD) require careful anticoagulation because thrombotic and bleeding risks are both elevated. We evaluated the efficacy and safety of warfarin, direct oral anticoagulants (DOACs), and no anticoagulation in Korean patients with ESKD and AF. Methods: In this multicenter retrospective study, we included 933 patients with ESKD and nonvalvular AF treated between 2010 and 2023. Patients were assigned to three groups by initial treatment: no anticoagulation (n = 604), warfarin (n = 197), or DOACs (n = 132). The primary efficacy outcome was ischemic stroke or systemic embolism (IS/SE); the primary safety outcome was major bleeding (MB). Secondary outcomes were intracranial hemorrhage (ICH), gastrointestinal bleeding (GIB), and all-cause mortality. Inverse probability of treatment weighting was used to adjust for confounding. Results: Both warfarin (adjusted hazard ratio [aHR], 0.55) and DOACs (aHR, 0.36) significantly reduced the risk of IS/SE compared with no anticoagulation. However, warfarin increased MB risk compared with no anticoagulation (aHR, 2.69), including ICH and GIB. DOACs also increased MB risk versus no anticoagulation (aHR, 1.37), driven primarily by ICH. Compared with warfarin, DOACs showed a lower MB risk (aHR, 0.51). Both warfarin and DOACs reduced all-cause mortality relative to no anticoagulation (aHR, 0.53 and 0.57, respectively). Conclusions Among Korean patients with ESKD and AF, both warfarin and DOACs reduced IS/SE but increased MB. Given their lower MB risk than warfarin, DOACs may be preferable for anticoagulation in this high-risk population.

Background: Erythema multiforme (EM) is typically a self-limited, acute hypersensitivity reaction. However, a subset of patients experiences chronic, recurrent episodes, for which clinical features and treatment strategies differ depending on the underlying etiology, especially in herpes simplex virus (HSV)-associated cases. Objective: To investigate the clinical and phenotypic features of chronic recurrent EM and assess treatment responses, with a focus on differences based on HSV association. Methods: This retrospective study included pathology-confirmed cases of suspected EM from 2010 to 2023. Forty patients with chronic EM (≥3 recurrences or persistent disease for ≥12 months) were included. Clinical, histopathologic, and serologic data were analysed.Patients were stratified into herpes simplex virus-associated erythema multiforme (HAEM) and non-HAEM groups. Clustering analysis was performed to identify clinical phenotypes.Treatment responses to antivirals and immunomodulators were evaluated. Results: Of the 40 patients, 24 (60%) were classified as HAEM. HAEM patients showed more mucosal involvement, smaller targetoid lesions, and acral predominance, while nonHAEM patients had larger, coalescing lesions with more trunk involvement. Cluster analysis supported HSV as the major discriminating factor. Antiviral agents were effective in 87.5% of HAEM cases but ineffective in 76.9% of non-HAEM patients. Immunosuppressants such as cyclosporine and mycophenolate mofetil showed variable responses. Baricitinib induced complete remission in all 3 refractory cases. Conclusion HSV association defines a distinct clinical subtype of chronic recurrent EM, with differences in lesion morphology, distribution, and treatment response. Recognizing these patterns may guide targeted therapeutic strategies, including the potential use of Janus kinase inhibitors in refractory cases.

Sarcopenia is a major geriatric syndrome characterized by progressive loss of muscle mass and strength, resulting in disability and mortality. This narrative review synthesizes international consensus recommendations and Korean evidence to guide context-specific sarcopenia management strategies. PubMed, Embase, Cochrane Library, and KoreaMed (January 2000–November 2025) were searched, focusing on randomized trials, meta-analyses, systematic reviews, clinical practice guidelines, and large observational studies. Global diagnostic frameworks have evolved from muscle mass-based definitions toward multidimensional models that incorporate muscle strength and physical performance. Exercise and nutrition remain the mainstay treatments, with resistance-based training and adequate protein intake. Currently, pharmacologic options with proven clinical benefit are limited. In Korea, growing evidence supports the effectiveness of community-based sarcopenia interventions, underscoring the need for standardized, integrated delivery models that bridge the fragmented healthcare system and enable sustainable implementation.

Background: s/Aims: Phase angle (PhA), as measured by bioelectrical impedance analysis, provides insights into hydration and nutritional status, making it a prognostic indicator of frailty. While low preoperative PhA has been linked to postoperative complications in cancer patients, its predictive value in individuals undergoing pancreaticoduodenectomy (PD) has not been thoroughly investigated.This study aims to evaluate the clinical utility of preoperative PhA in predicting postoperative complications for patients undergoing PD. Methods: Among 41 patients who underwent PD at Seoul National University Hospital between September and December 2024, 35 were included in the analysis after excluding 6 patients who had concomitant blood vessel or other organ resections. Patients were divided into low (Comprehensive Complication Index [CCI] ≤ 20) and high (CCI > 20) complication groups based on the CCI, derived from the Clavien–Dindo classification. The differences in PhA between the two groups were analyzed, and logistic regression was performed to assess the relationship between PhA and CCI. Results: The mean PhA was significantly lower in the high-CCI group compared to the low-CCI group (5.7° vs. 6.7°, p = 0.025). Multivariate logistic regression analysis indicated that PhA (odds ratio: 0.17; 95% confidence interval: 0.04–0.68; p = 0.012) was an independent predictor of high CCI. A low preoperative PhA was associated with an increased risk of postoperative complications following PD. Conclusions Preoperative PhA may serve as a valuable predictive indicator of postoperative complications after PD, enabling the identification of patients who could benefit from preoperative prehabilitation, including nutritional support.

Background: Recent advancements in large language models (LLMs) have accelerated their integration into clinical domains, including laboratory medicine. The performance of LLMs in answering board-level laboratory medicine questions has not been comprehensively evaluated. Given the importance of diagnostic accuracy in this field, rigorous and objective evaluations of LLM capabilities are essential. Methods: We assessed 12 LLMs from OpenAI, Anthropic, and Google using 320 Korean Residency Examination questions (2021–2024) spanning six laboratory medicine subspecialties. Standardized prompts were provided via their application programming interfaces under deterministic settings (temperature = 0). Questions were administered thrice to assess response reproducibility. Outputs were compared with validated answers and analyzed for accuracy, reasoning quality, and error typology. Results: Google’s Gemini 2.0 Pro achieved the highest accuracy (80.0%), followed by OpenAI’s GPT-4.5 (77.2%) and Anthropic’s Claude 3.7 Sonnet (74.1%). Accuracy decreased as the difficulty of questions increased (78.0% for easy vs. 45.1% for challenging). Subspecialty performance varied. Al models underperformed on questions on transfusion medicine (mean accuracy: 38.8%), primarily because of limitations in domain-specific and regional knowledge representations. Incorrect answers primarily resulted from reasoning errors. Reproducibility exceeded 95% for most models; however, some residual non-determinism appeared even with greedy decoding (temperature = 0). Conclusions LLMs demonstrated substantial potential for integration into laboratory medicine, particularly in clinical chemistry and immunology. Performance inconsistencies (particularly for high-difficulty questions) and knowledge gaps (notably for transfusion medicine) highlight the necessity for further development—potentially including domain-specific fine-tuning and retrieval-augmented generation integration—and robust expert oversight before clinical application.