1.Rapid Recovery From SARS-CoV-2Infection Among Immunocompromised Children Despite Limited Neutralizing Antibody Response: A Virologic and Sero-Immunologic Analysis of a Single-Center Cohort
Doo Ri KIM ; Byoung Kwon PARK ; Jin Yang BAEK ; Areum SHIN ; Ji Won LEE ; Hee Young JU ; Hee Won CHO ; Keon Hee YOO ; Ki Woong SUNG ; Chae-Hong JEONG ; Tae Yeul KIM ; June-Young KOH ; Jae-Hoon KO ; Yae-Jean KIM
Journal of Korean Medical Science 2025;40(12):e52-
Background:
Immunocompromised (IC) pediatric patients are at increased risk of severe acute respiratory syndrome coronavirus 2 infection, but the viral kinetics and seroimmunologic response in pediatric IC patients are not fully understood.
Methods:
From April to June 2022, a prospective cohort study was conducted. IC pediatric patients hospitalized for coronavirus disease 2019 (COVID-19) were enrolled. Serial saliva swab and serum specimens were subjected to reverse transcription polymerase chain reaction assays with mutation sequencing, viral culture, anti-spike-protein, anti-nucleocapsid antibody assays, plaque reduction neutralization test (PRNT) and multiplex cytokine assays.
Results:
Eleven IC children were evaluated. Their COVID-19 symptoms resolved promptly (median, 2.5 days; interquartile range, 2.0–4.3). Saliva swab specimens contained lower viral loads than nasopharyngeal swabs (P = 0.008). All cases were BA.2 infection, and 45.5% tested negative within 14 days by saliva swab from symptom onset. Eight (72.7%) showed a time-dependent increase in BA.2 PRNT titers, followed by rapid waning. Multiplex cytokine assays revealed that monocyte/macrophage activation and Th 1 responses were comparable to those of non-IC adults. Activation of interleukin (IL)-1Ra and IL-6 was brief, and IL-17A was suppressed. Activated interferon (IFN)-γ and IL-18/IL-1F4 signals were observed.
Conclusion
IC pediatric patients rapidly recovered from COVID-19 with low viral loads.Antibody response was limited, but cytokine analysis suggested an enhanced IFN-γ- and IL-18-mediated immune response without excessive activation of inflammatory cascades. To validate our observation, immune cell-based functional studies need to be conducted among IC and non-IC children.
2.Rapid Recovery From SARS-CoV-2Infection Among Immunocompromised Children Despite Limited Neutralizing Antibody Response: A Virologic and Sero-Immunologic Analysis of a Single-Center Cohort
Doo Ri KIM ; Byoung Kwon PARK ; Jin Yang BAEK ; Areum SHIN ; Ji Won LEE ; Hee Young JU ; Hee Won CHO ; Keon Hee YOO ; Ki Woong SUNG ; Chae-Hong JEONG ; Tae Yeul KIM ; June-Young KOH ; Jae-Hoon KO ; Yae-Jean KIM
Journal of Korean Medical Science 2025;40(12):e52-
Background:
Immunocompromised (IC) pediatric patients are at increased risk of severe acute respiratory syndrome coronavirus 2 infection, but the viral kinetics and seroimmunologic response in pediatric IC patients are not fully understood.
Methods:
From April to June 2022, a prospective cohort study was conducted. IC pediatric patients hospitalized for coronavirus disease 2019 (COVID-19) were enrolled. Serial saliva swab and serum specimens were subjected to reverse transcription polymerase chain reaction assays with mutation sequencing, viral culture, anti-spike-protein, anti-nucleocapsid antibody assays, plaque reduction neutralization test (PRNT) and multiplex cytokine assays.
Results:
Eleven IC children were evaluated. Their COVID-19 symptoms resolved promptly (median, 2.5 days; interquartile range, 2.0–4.3). Saliva swab specimens contained lower viral loads than nasopharyngeal swabs (P = 0.008). All cases were BA.2 infection, and 45.5% tested negative within 14 days by saliva swab from symptom onset. Eight (72.7%) showed a time-dependent increase in BA.2 PRNT titers, followed by rapid waning. Multiplex cytokine assays revealed that monocyte/macrophage activation and Th 1 responses were comparable to those of non-IC adults. Activation of interleukin (IL)-1Ra and IL-6 was brief, and IL-17A was suppressed. Activated interferon (IFN)-γ and IL-18/IL-1F4 signals were observed.
Conclusion
IC pediatric patients rapidly recovered from COVID-19 with low viral loads.Antibody response was limited, but cytokine analysis suggested an enhanced IFN-γ- and IL-18-mediated immune response without excessive activation of inflammatory cascades. To validate our observation, immune cell-based functional studies need to be conducted among IC and non-IC children.
3.Explainable paroxysmal atrial fibrillation diagnosis using an artificial intelligence-enabled electrocardiogram
Yeongbong JIN ; Bonggyun KO ; Woojin CHANG ; Kang-Ho CHOI ; Ki Hong LEE
The Korean Journal of Internal Medicine 2025;40(2):251-261
Background/Aims:
Atrial fibrillation (AF) significantly contributes to global morbidity and mortality. Paroxysmal atrial fibrillation (PAF) is particularly common among patients with cryptogenic strokes or transient ischemic attacks and has a silent nature. This study aims to develop reliable artificial intelligence (AI) algorithms to detect early signs of AF in patients with normal sinus rhythm (NSR) using a 12-lead electrocardiogram (ECG).
Methods:
Between 2013 and 2020, 552,372 ECG traces from 318,321 patients were collected and split into training (n = 331,422), validation (n = 110,475), and test sets (n = 110,475). Deep neural networks were then trained to predict AF onset within one month of NSR. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). An explainable AI technique was employed to identify the inference evidence underlying the predictions of deep learning models.
Results:
The AUROC for early diagnosis of PAF was 0.905 ± 0.007. The findings reveal that the vicinity of the T wave, including the ST segment and S-peak, significantly influences the ability of the trained neural network to diagnose PAF. Additionally, comparing the summarized ECG in NSR with those in PAF revealed that nonspecific ST-T abnormalities and inverted T waves were associated with PAF.
Conclusions
Deep learning can predict AF onset from NSR while detecting key features that influence decisions. This suggests that identifying undetected AF may serve as a predictive tool for PAF screening, offering valuable insights into cardiac dysfunction and stroke risk.
4.Explainable paroxysmal atrial fibrillation diagnosis using an artificial intelligence-enabled electrocardiogram
Yeongbong JIN ; Bonggyun KO ; Woojin CHANG ; Kang-Ho CHOI ; Ki Hong LEE
The Korean Journal of Internal Medicine 2025;40(2):251-261
Background/Aims:
Atrial fibrillation (AF) significantly contributes to global morbidity and mortality. Paroxysmal atrial fibrillation (PAF) is particularly common among patients with cryptogenic strokes or transient ischemic attacks and has a silent nature. This study aims to develop reliable artificial intelligence (AI) algorithms to detect early signs of AF in patients with normal sinus rhythm (NSR) using a 12-lead electrocardiogram (ECG).
Methods:
Between 2013 and 2020, 552,372 ECG traces from 318,321 patients were collected and split into training (n = 331,422), validation (n = 110,475), and test sets (n = 110,475). Deep neural networks were then trained to predict AF onset within one month of NSR. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). An explainable AI technique was employed to identify the inference evidence underlying the predictions of deep learning models.
Results:
The AUROC for early diagnosis of PAF was 0.905 ± 0.007. The findings reveal that the vicinity of the T wave, including the ST segment and S-peak, significantly influences the ability of the trained neural network to diagnose PAF. Additionally, comparing the summarized ECG in NSR with those in PAF revealed that nonspecific ST-T abnormalities and inverted T waves were associated with PAF.
Conclusions
Deep learning can predict AF onset from NSR while detecting key features that influence decisions. This suggests that identifying undetected AF may serve as a predictive tool for PAF screening, offering valuable insights into cardiac dysfunction and stroke risk.
5.Explainable paroxysmal atrial fibrillation diagnosis using an artificial intelligence-enabled electrocardiogram
Yeongbong JIN ; Bonggyun KO ; Woojin CHANG ; Kang-Ho CHOI ; Ki Hong LEE
The Korean Journal of Internal Medicine 2025;40(2):251-261
Background/Aims:
Atrial fibrillation (AF) significantly contributes to global morbidity and mortality. Paroxysmal atrial fibrillation (PAF) is particularly common among patients with cryptogenic strokes or transient ischemic attacks and has a silent nature. This study aims to develop reliable artificial intelligence (AI) algorithms to detect early signs of AF in patients with normal sinus rhythm (NSR) using a 12-lead electrocardiogram (ECG).
Methods:
Between 2013 and 2020, 552,372 ECG traces from 318,321 patients were collected and split into training (n = 331,422), validation (n = 110,475), and test sets (n = 110,475). Deep neural networks were then trained to predict AF onset within one month of NSR. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). An explainable AI technique was employed to identify the inference evidence underlying the predictions of deep learning models.
Results:
The AUROC for early diagnosis of PAF was 0.905 ± 0.007. The findings reveal that the vicinity of the T wave, including the ST segment and S-peak, significantly influences the ability of the trained neural network to diagnose PAF. Additionally, comparing the summarized ECG in NSR with those in PAF revealed that nonspecific ST-T abnormalities and inverted T waves were associated with PAF.
Conclusions
Deep learning can predict AF onset from NSR while detecting key features that influence decisions. This suggests that identifying undetected AF may serve as a predictive tool for PAF screening, offering valuable insights into cardiac dysfunction and stroke risk.
6.Rapid Recovery From SARS-CoV-2Infection Among Immunocompromised Children Despite Limited Neutralizing Antibody Response: A Virologic and Sero-Immunologic Analysis of a Single-Center Cohort
Doo Ri KIM ; Byoung Kwon PARK ; Jin Yang BAEK ; Areum SHIN ; Ji Won LEE ; Hee Young JU ; Hee Won CHO ; Keon Hee YOO ; Ki Woong SUNG ; Chae-Hong JEONG ; Tae Yeul KIM ; June-Young KOH ; Jae-Hoon KO ; Yae-Jean KIM
Journal of Korean Medical Science 2025;40(12):e52-
Background:
Immunocompromised (IC) pediatric patients are at increased risk of severe acute respiratory syndrome coronavirus 2 infection, but the viral kinetics and seroimmunologic response in pediatric IC patients are not fully understood.
Methods:
From April to June 2022, a prospective cohort study was conducted. IC pediatric patients hospitalized for coronavirus disease 2019 (COVID-19) were enrolled. Serial saliva swab and serum specimens were subjected to reverse transcription polymerase chain reaction assays with mutation sequencing, viral culture, anti-spike-protein, anti-nucleocapsid antibody assays, plaque reduction neutralization test (PRNT) and multiplex cytokine assays.
Results:
Eleven IC children were evaluated. Their COVID-19 symptoms resolved promptly (median, 2.5 days; interquartile range, 2.0–4.3). Saliva swab specimens contained lower viral loads than nasopharyngeal swabs (P = 0.008). All cases were BA.2 infection, and 45.5% tested negative within 14 days by saliva swab from symptom onset. Eight (72.7%) showed a time-dependent increase in BA.2 PRNT titers, followed by rapid waning. Multiplex cytokine assays revealed that monocyte/macrophage activation and Th 1 responses were comparable to those of non-IC adults. Activation of interleukin (IL)-1Ra and IL-6 was brief, and IL-17A was suppressed. Activated interferon (IFN)-γ and IL-18/IL-1F4 signals were observed.
Conclusion
IC pediatric patients rapidly recovered from COVID-19 with low viral loads.Antibody response was limited, but cytokine analysis suggested an enhanced IFN-γ- and IL-18-mediated immune response without excessive activation of inflammatory cascades. To validate our observation, immune cell-based functional studies need to be conducted among IC and non-IC children.
7.Rapid Recovery From SARS-CoV-2Infection Among Immunocompromised Children Despite Limited Neutralizing Antibody Response: A Virologic and Sero-Immunologic Analysis of a Single-Center Cohort
Doo Ri KIM ; Byoung Kwon PARK ; Jin Yang BAEK ; Areum SHIN ; Ji Won LEE ; Hee Young JU ; Hee Won CHO ; Keon Hee YOO ; Ki Woong SUNG ; Chae-Hong JEONG ; Tae Yeul KIM ; June-Young KOH ; Jae-Hoon KO ; Yae-Jean KIM
Journal of Korean Medical Science 2025;40(12):e52-
Background:
Immunocompromised (IC) pediatric patients are at increased risk of severe acute respiratory syndrome coronavirus 2 infection, but the viral kinetics and seroimmunologic response in pediatric IC patients are not fully understood.
Methods:
From April to June 2022, a prospective cohort study was conducted. IC pediatric patients hospitalized for coronavirus disease 2019 (COVID-19) were enrolled. Serial saliva swab and serum specimens were subjected to reverse transcription polymerase chain reaction assays with mutation sequencing, viral culture, anti-spike-protein, anti-nucleocapsid antibody assays, plaque reduction neutralization test (PRNT) and multiplex cytokine assays.
Results:
Eleven IC children were evaluated. Their COVID-19 symptoms resolved promptly (median, 2.5 days; interquartile range, 2.0–4.3). Saliva swab specimens contained lower viral loads than nasopharyngeal swabs (P = 0.008). All cases were BA.2 infection, and 45.5% tested negative within 14 days by saliva swab from symptom onset. Eight (72.7%) showed a time-dependent increase in BA.2 PRNT titers, followed by rapid waning. Multiplex cytokine assays revealed that monocyte/macrophage activation and Th 1 responses were comparable to those of non-IC adults. Activation of interleukin (IL)-1Ra and IL-6 was brief, and IL-17A was suppressed. Activated interferon (IFN)-γ and IL-18/IL-1F4 signals were observed.
Conclusion
IC pediatric patients rapidly recovered from COVID-19 with low viral loads.Antibody response was limited, but cytokine analysis suggested an enhanced IFN-γ- and IL-18-mediated immune response without excessive activation of inflammatory cascades. To validate our observation, immune cell-based functional studies need to be conducted among IC and non-IC children.
8.Explainable paroxysmal atrial fibrillation diagnosis using an artificial intelligence-enabled electrocardiogram
Yeongbong JIN ; Bonggyun KO ; Woojin CHANG ; Kang-Ho CHOI ; Ki Hong LEE
The Korean Journal of Internal Medicine 2025;40(2):251-261
Background/Aims:
Atrial fibrillation (AF) significantly contributes to global morbidity and mortality. Paroxysmal atrial fibrillation (PAF) is particularly common among patients with cryptogenic strokes or transient ischemic attacks and has a silent nature. This study aims to develop reliable artificial intelligence (AI) algorithms to detect early signs of AF in patients with normal sinus rhythm (NSR) using a 12-lead electrocardiogram (ECG).
Methods:
Between 2013 and 2020, 552,372 ECG traces from 318,321 patients were collected and split into training (n = 331,422), validation (n = 110,475), and test sets (n = 110,475). Deep neural networks were then trained to predict AF onset within one month of NSR. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). An explainable AI technique was employed to identify the inference evidence underlying the predictions of deep learning models.
Results:
The AUROC for early diagnosis of PAF was 0.905 ± 0.007. The findings reveal that the vicinity of the T wave, including the ST segment and S-peak, significantly influences the ability of the trained neural network to diagnose PAF. Additionally, comparing the summarized ECG in NSR with those in PAF revealed that nonspecific ST-T abnormalities and inverted T waves were associated with PAF.
Conclusions
Deep learning can predict AF onset from NSR while detecting key features that influence decisions. This suggests that identifying undetected AF may serve as a predictive tool for PAF screening, offering valuable insights into cardiac dysfunction and stroke risk.
9.Explainable paroxysmal atrial fibrillation diagnosis using an artificial intelligence-enabled electrocardiogram
Yeongbong JIN ; Bonggyun KO ; Woojin CHANG ; Kang-Ho CHOI ; Ki Hong LEE
The Korean Journal of Internal Medicine 2025;40(2):251-261
Background/Aims:
Atrial fibrillation (AF) significantly contributes to global morbidity and mortality. Paroxysmal atrial fibrillation (PAF) is particularly common among patients with cryptogenic strokes or transient ischemic attacks and has a silent nature. This study aims to develop reliable artificial intelligence (AI) algorithms to detect early signs of AF in patients with normal sinus rhythm (NSR) using a 12-lead electrocardiogram (ECG).
Methods:
Between 2013 and 2020, 552,372 ECG traces from 318,321 patients were collected and split into training (n = 331,422), validation (n = 110,475), and test sets (n = 110,475). Deep neural networks were then trained to predict AF onset within one month of NSR. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). An explainable AI technique was employed to identify the inference evidence underlying the predictions of deep learning models.
Results:
The AUROC for early diagnosis of PAF was 0.905 ± 0.007. The findings reveal that the vicinity of the T wave, including the ST segment and S-peak, significantly influences the ability of the trained neural network to diagnose PAF. Additionally, comparing the summarized ECG in NSR with those in PAF revealed that nonspecific ST-T abnormalities and inverted T waves were associated with PAF.
Conclusions
Deep learning can predict AF onset from NSR while detecting key features that influence decisions. This suggests that identifying undetected AF may serve as a predictive tool for PAF screening, offering valuable insights into cardiac dysfunction and stroke risk.
10.Sites of Metastasis and Survival in Metastatic Renal Cell Carcinoma:Results From the Korean Renal Cancer Study Group Database
Chan Ho LEE ; Minyong KANG ; Cheol KWAK ; Young Hwii KO ; Jung Kwon KIM ; Jae Young PARK ; Seokhwan BANG ; Seong Il SEO ; Jungyo SUH ; Wan SONG ; Cheryn SONG ; Hyung Ho LEE ; Jinsoo CHUNG ; Chang Wook JEONG ; Jung Ki JO ; Seock Hwan CHOI ; Joongwon CHOI ; Changil CHOI ; Seol Ho CHOO ; Jang Hee HAN ; Sung-Hoo HONG ; Eu Chang HWANG
Journal of Korean Medical Science 2024;39(45):e293-
Background:
In patients with metastatic renal cell carcinoma (mRCC), sites of metastatic involvement have been reported to be associated with a difference in survival. However, the frequency and survival according to different sites of metastases in Korean patients with mRCC remain unclear. Therefore, this study aimed to assess the frequency of metastatic site involvement and the association between sites of metastatic involvement and survival in Korean patients with mRCC.
Methods:
This retrospective study used the multicenter cohort of the Korean Renal Cancer Study Group mRCC database to identify patients who started targeted therapy between December 2005 and March 2018. Data on the frequency of metastatic organ involvement at the time of mRCC diagnosis and oncologic outcomes according to different sites of metastasis were analyzed.
Results:
A total of 1,761 patients were eligible for analysis. Of the 1,761 patients, 1,564 (88.8%) had clear cell RCC, and 1,040 (59.1%) had synchronous metastasis. The median number of metastasis sites was 2 (interquartile range [IQR], 1–6). The median age at the initiation of systemic therapy was 60 years (IQR, 29–88), 1,380 (78.4%) were men, and 1,341 (76.1%) underwent nephrectomy. Based on the International Metastatic Renal Cell Carcinoma Database Consortium model, patients were stratified into favorable-, intermediate-, and poor-risk groups with 359 (20.4%), 1,092 (62.0%), and 310 (17.6%) patients, respectively. The lung (70.9%), lymph nodes (37.9%), bone (30.7%), liver (12.7%), adrenal gland (9.8%), and brain (8.2%) were the most common sites of metastasis, followed by the pancreas, pleura, peritoneum, spleen, thyroid, and bowel. Among the most common sites of metastasis (> 5%), the median cancer-specific survival (CSS) ranged from 13.9 (liver) to 29.1 months (lung). An association was observed between liver, bone, and pleural metastases and the shortest median CSS (< 19 months).
Conclusion
In Korean patients with mRCC, metastases to the lung, lymph nodes, bone, liver, adrenal gland, and brain were more frequent than those to other organs. Metastases to the liver, bone, and pleura were associated with poor CSS. The findings of this study may be valuable for patient counseling and guiding future study designs.

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