Primary antibody deficiency (PAD) is the most common form of primary immunodeficiency (PID) in adults, although the overall prevalence remains low. Recent studies have suggested a rising incidence due to changes in environmental factors and increased awareness. PID typically presents with recurrent upper and lower respiratory tract infections but may also be associated with allergic and autoimmune diseases, resulting in various clinical manifestations. This report presents three representative adult cases of PAD— X-linked agammaglobulinemia (XLA), common variable immunodeficiency (CVID), and IgG3 subclass deficiency (IgG3D) with bronchial asthma—offering insights into their diagnosis and long-term management. These cases emphasize the need to suspect XLA in patients with recurrent pneumonia and bronchiectasis, to recognize chronic severe urticaria as a potential clinical clue for CVID, and to evaluate IgG3D in asthma patients with frequent viral infections despite standard care. Through these examples, this clinical insight underscores the importance of early suspicion of PID, comprehensive immunological evaluation and individualized treatment strategies in improving outcomes for adult PID patients.

Purpose: Our study identified prognostic factors affecting visual outcomes in patients with unilateral indirect traumatic optic neuropathy (TON), determined the risk of legal blindness, and assessed changes in visual acuity, visual fields, retinal structure, and the therapeutic effect of high-dose corticosteroid treatment. Methods: We retrospectively reviewed the medical records of 52 patients (52 eyes) diagnosed with TON between 2014 and 2023. Patients were categorized into two groups according to the final best-corrected visual acuity (BCVA): Group 1 (BCVA ≥0.1) and Group 2 (BCVA <0.1). Prognostic factors were analyzed using logistic regression, and receiver operating characteristic curve analysis was performed to determine optimal cutoff values. Longitudinal changes in visual acuity, visual field index (VFI), and retinal structural parameters were assessed using a generalized linear mixed model. Results: Factors significantly associated with Group 1 included the absence of intracranial hemorrhage, administration of high-dose steroids within 24 h, and better logMAR visual acuity and VFI within 4 weeks post-trauma. In multivariate analysis, VFI within 4 weeks remained significantly associated with favorable visual outcomes (p = 0.008). The optimal VFI cutoff value for predicting a good prognosis was 13%, yielding a sensitivity of 90% and specificity of 93.3%. Visual acuity outcomes over time differed significantly according to the timing of high-dose steroid administration. Conclusions VFI within 4 weeks after injury was the most reliable prognostic indicator, demonstrating high sensitivity and specificity for predicting legal blindness. Early administration of high-dose steroids within 24 h helped prevent visual deterioration. These findings emphasize the importance of early quantitative assessment of visual function and prompt therapeutic intervention to guide treatment strategies in patients with TON.

The gut microbiome is not just a bystander of colorectal carcinogenesis but is an active driver of colorectal cancer (CRC). CRC-associated microbiome contributes in the tumorigenesis through chronic inflammation, formation of toxic metabolite and genotoxins, oncogenic signal activation, immune evasion, and barrier disruption—all reinforcing a tumor microenvironment. In contrast, beneficial microbiome supports the barrier-immune-metabolic axis by maintaining mucosal integrity and balanced immune tone. Despite extensive studies of microbiome-based CRC biomarkers, microbiome-based CRC biomarkers have not been yet ready for routine clinical use due to variation across populations and lack of standardization of key steps such as sampling, analysis, cutoffs, and interpretation. Microbiome-based therapies aim to change the overall intestinal ecosystem rather than simply adding or removing single strains. At present, dietary modulation and prebiotics are considered supportive measures, while probiotics or synbiotics are in preclinical stage. Fecal microbiota transplantation (FMT) still faces important challenges in effectiveness, standardization and safety. By its role in reshaping the tumor–host immune environment, FMT is viewed as a potential option for cancer therapy after further development through well-controlled clinical trials with careful safety monitoring.

Background: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is among the most important multidrug-resistant pathogens causing bloodstream infections (BSIs).Cefotaximase (CTX-M) enzymes are the most common and highly diverse ESBL family in E.coli. CTX-M-15 in group CTX-M-1 and CTX-M-14 in group CTX-M-9 are the most extensively disseminated enzymes. Multidrug-resistant E. coli strains complicate empirical therapy and increase healthcare burden globally and in Korea. We investigated the molecular epidemiology, sequence types (STs), and ESBL genotypes of E. coli bloodstream isolates in Korea and identified clinical risk factors for cefotaxime resistance. Methods: We collected all non-duplicated isolates of E. coli and related clinical information from patients with BSIs at eight sentinel hospitals in the Korean Global Antimicrobial Resistance Surveillance System (Kor-GLASS) collection network during 2017–2021. Duplicate isolates were removed to ensure representativeness of the data. Antimicrobial susceptibility was tested using disk diffusion tests, and multilocus sequence typing and betalactamase genotyping were performed. Results: Among 9,232 E. coli blood isolates, resistance rates to cefotaxime and ceftazidime were 36.4% and 11.4%, respectively. Among the clinical factors, age > 65 yrs (adjusted odds ratio [aOR], 1.36), hospital-origin infection (aOR, 2.55), and admission type (intensive care unit [ICU] vs. general ward; aOR, 1.34) were significant cefotaxime resistance risk factors. ST131 was the most prevalent among cefotaxime-resistant E. coli (64.8%, 2,180/3,363), followed by ST1193 (5.3%, N = 177), and ST69 (5.1%, N = 170).ST131, ST648, ST405, and ST410 cefotaxime-resistant E. coli isolates frequently harbored blaCTX-M-15, whereas ST1193 and ST68 showed a high proportion of blaCTX-M-27 carriers, and most ST457 and ST5150 isolates carried blaCTX-M-55. Conclusions Continuous monitoring of ESBL-producing E. coli is required to prevent further dissemination, guide empirical therapy, inform infection control policies, and ensure early detection of multidrug-resistant clones with the potential for widespread transmission.

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.

Background: Fusion genes are major drivers of acute leukemia. Conventional diagnostics are limited in detecting the diverse fusions included in recently updated acute leukemia classifications. We evaluated the fusion detection performance of RNA sequencing (RNAseq) compared with that of conventional diagnostics in patients with acute leukemia. Methods: We retrospectively obtained the data of 101 patients with acute leukemia who underwent conventional diagnostics (i.e., karyotyping, FISH, or multiplex reverse transcription PCR) at diagnosis at Samsung Medical Center, Seoul, Korea, between September 2022 and September 2023. Whole RNA-seq was performed using the Illumina Stranded mRNA Prep kit (Illumina, San Diego, CA, USA). The concordance, sensitivity, and specificity of RNA-seq for fusion gene detection were compared with those of conventional diagnostics. Results: RNA-seq helped identify 52 fusion genes in 51 (50.5%) of 101 patients, with detection rates of 40.7%, 70.3%, 37.5%, and 50% in acute myeloid leukemia, B-cell acute lymphoblastic leukemia, T-cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia, respectively. RNA-seq showed 83.3% sensitivity and 80.8% concordance with conventional diagnostics; it missed eight fusions, likely because of low transcript abundance or enhancer hijacking. RNA-seq also helped clarify three previously unspecified rearrangements and detected 12 fusions (21.4%) in 56 cases that tested negative with conventional diagnostics, including four novel (KMT2A::THAP12 , RUNX1::PRPF19 , MLLT10::UBE2L6, and FUS::ZNF362) and three rare (HNRNPH1::ERG, RUNX1::USP42, and ETV6::NCOA2) fusions. Conclusions This was the first study to evaluate the performance of whole RNA-seq in fusion detection in patients with acute leukemia in Korea. Incorporating RNA-seq into diagnostic workflows may facilitate earlier and more precise therapeutic decisions and improve prognostic assessment in patients with acute leukemia.

A medial closing wedge supramalleolar osteotomy, along with corrections for pes plano-valgus, including medial displacement calcaneal osteotomy, and deltoid ligament repair or reconstruction, is most commonly considered for the joint-preserving surgery of valgus ankle arthritis. In cases of ‘opposing coronal plane deformities,’ however, where the tibial plafond is varus-aligned to the long axis of the tibia and the ground, while the talus is conversely valgus-aligned, medial closing wedge supramalleolar osteotomy may paradoxically risk exacerbating the valgus ankle arthritis. This paper reports the radiological and clinical outcomes of an otherwise healthy, physically active 55-year-old male patient with valgus ankle arthritis and opposing coronal-plane deformities, along with a literature review. The patient underwent joint-preserving surgery consisting of lateral closing wedge supramalleolar osteotomy, fibular osteotomy, medial displacement calcaneal osteotomy, and deltoid ligament augmentation with suture tape. This paper discusses the critical considerations and surgical precautions necessary when deciding on joint-preserving procedures for valgus ankle arthritis.

Objective: Thoracic pedicle screw fixation is technically demanding because of the natural variability in pedicle anatomy, a challenge that is further exacerbated in patients with spinal tumors who often have compromised pedicles. The L-point entry, juxtapedicular, and endplate-parallel trajectory (L-JET) technique was developed to provide a uniform entry point, a predictable screw trajectory, and the capacity to accommodate larger-diameter screws at levels T3–10. This study aimed to evaluate the safety and feasibility of the L-JET technique in comparison with the conventional transpedicular method. Methods: A comparative analysis of consecutively collected data was performed to evaluate outcomes associated with the L-JET technique in patients undergoing surgery for thoracic extradural spinal tumors. The L-point was defined as the intersection of a vertical line along the lateral margin of the facet joint and a horizontal line along the upper edge of the transverse process. The screw trajectory was planned with 30° of medial convergence in the axial plane, creating a juxtapedicular path, and a straightforward trajectory in the sagittal plane. Primary outcome measures included screw diameter, screw length, cortical breach rate, and the need for revision surgery, as assessed using computed tomography scans and medical records. Results: A total of 108 screws were placed in 22 patients using the L-JET technique, while 98 screws were placed in 18 patients using the conventional technique. The L-JET group used significantly larger-diameter screws (6.06±0.65 mm) than the conventional group (5.74±0.80 mm, p=0.02), with no significant difference observed in screw length between groups. Medial cortical breach occurred in one screw in each group, and no supra- or infrapedicular breaches were identified. No screw-related neurovascular complications or revision surgeries occurred in either group. Conclusion The L-JET technique enables consistent screw placement with larger-diameter screws, even in compromised pedicles associated with thoracic spinal tumors, without increasing the risk of complications or the need for revision surgery.

Background/Aims: Gastroesophageal reflux disease (GERD) after peroral endoscopic myotomy (POEM) is a significant challenge. Disruption of the lower esophageal sphincter during POEM and dysfunction of the crural diaphragm, which contributes to esophagogastric junction pressure, may lead to GERD after POEM. We aim to identify predictors of GERD after POEM and focus on physiological parameters of esophagogastric junction pressure in patients with achalasia before POEM. Methods: We retrospectively analyzed a prospectively collected database of patients who underwent POEM between July 2016 and August 2023. Ninety-two patients with achalasia who underwent high-resolution manometry and endoscopy before and after POEM were included. Results: Forty-nine (53.3%) patients were diagnosed with GERD. Patient demographics, achalasia subtypes, prior treatments, myotomy length, and myotomy orientation were not associated with GERD after POEM. Loss of inspiratory augmentation before POEM was associated with GERD after POEM (P < 0.05). GERD occurred more frequently in patients with a shorter intra-abdominal lower esophageal sphincter length before POEM. Type III esophagogastric junction morphology in the GERD group (37.1%) was more common than that in the non-GERD group (15.8%). Loss of inspiratory augmentation occurred more frequently in patients with type III esophagogastric junction pressure morphology. Conclusion Loss of inspiratory augmentation may predict GERD after POEM.

Background/Aims: Nocturnal acid reflux disrupts sleep and impairs quality of life. Proton pump inhibitors provide insufficient suppression of nocturnal acid secretion, whereas fexuprazan offers prolonged acid suppression. We compared the efficacy of fexuprazan and esomeprazole in controlling nocturnal reflux. Methods: In a randomized and crossover study, patients received fexuprazan or esomeprazole daily for 4 weeks, followed by a washout and crossover to the alternate medication for another 4 weeks, with a final washout completing the sequence. Severity (scores 0-10), frequency, sleep disturbance, and medication preferences were evaluated. Results: Thirty-nine patients were enrolled and randomized to receive either fexuprazan (n = 20) or esomeprazole (n = 19) first. After the first treatment, fexuprazan reduced severity from 7.5 ± 1.7 to 1.4 ± 1.7 (81.3% decrease), versus 7.8 ± 1.5 to 2.8 ± 1.9 (64.1% decrease) with esomeprazole (P = 0.012). In patients with severe symptoms (scores ≥ 7), fexuprazan led to significantly greater improvement than esomeprazole (P = 0.008). Following the first washout, the second crossover treatment resulted in greater improvement in symptom severity with fexuprazan (P = 0.001). During the second washout, nocturnal symptoms severity and frequencies were better controlled with fexuprazan than with esomeprazole (P = 0.005 and 0.019). Patients who switched from esomeprazole to fexuprazan preferred fexuprazan (P = 0.018). Conclusions Fexuprazan was more effective than esomeprazole in controlling nocturnal reflux symptom, particularly in patients with severe symptoms. Fexuprazan may offer a therapeutic advantage for patients with severe and persistent nocturnal reflux despite proton pump inhibitor therapy.