Fluorescence-Based Lateral Flow Immunoassay for Quantification of Infliximab: Analytical and Clinical Performance Evaluation

BACKGROUND

Therapeutic drug monitoring of infliximab (IFX) can improve treatment outcomes; however, the temporal gap between drug concentration monitoring and subsequent availability restricts its practical application. To address this issue, an automated monitoring method, AFIAS IFX, was developed to rapidly and accurately analyze IFX concentration in blood. The analytical and clinical performances of this method were assessed to establish its clinical utility.

METHODS

The analytical performance of AFIAS IFX was evaluated according to Clinical and Laboratory Standard Institute guidelines. For clinical validation, AFIAS IFX was compared with 3 established enzyme-linked immunosorbent assay kits (LISA TRACKER, RIDASCREEN, and ImmunoGuide) using 100 consecutive samples from 28 patients treated with IFX. Passing-Bablok regression and Bland-Altman analyses were performed to compare the methods.

RESULTS

The detection and quantification limits of AFIAS IFX were 0.12 and 0.20 mcg/mL, respectively. Furthermore, AFIAS IFX analyzed samples within 10 minutes for concentrations up to 50 mcg/mL, exhibiting reproducibility (coefficient of variation [CV] ≤7.8%) and accuracy (recovery 98%-101%) with serum, plasma, and whole blood samples. Clinically, it exhibited a good correlation with the 3 established enzyme-linked immunosorbent assay kits. For patients treated with Remicade (IFX), the Passing-Bablok regression slope was 1.001-1.259, with a mean difference of -1.48 to 0.28 mcg/mL. For patients treated with CT-P13, the Passing-Bablok regression slope was 0.974-1.254, with a mean difference of -2.44 to 0.15 mcg/mL.

CONCLUSIONS

AFIAS IFX, a novel fluorescence-based lateral flow assay, exhibited excellent performance in analyzing IFX trough levels and is a potentially powerful tool for therapeutic drug monitoring in clinical settings, with opportunities for further development.

A Bottom-Up Liquid Chromatography-Tandem Mass Spectrometry Method for Therapeutic Drug Monitoring of Infliximab: Method Development, Comparison With 2 Enzyme-Linked Immunosorbent Assay Methods, and Evaluation of Anti-Drug Antibody Interference

CONTEXT.—

Therapeutic drug monitoring is recommended to optimize infliximab use and improve outcome in chronic inflammatory disorders.

OBJECTIVE.—

To describe a simple and affordable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to measure infliximab in serum.

DESIGN.—

Infliximab was measured using winged stable isotope-labeled peptides as internal standards. Linearity, lower limit of measuring interval, limit of detection, precision, accuracy, carryover, and ion suppression were evaluated. Method comparison against 2 enzyme-linked immunosorbent assay (ELISA) methods (Remsima Monitor and IDKmonitor Infliximab) and anti-drug antibody (ADA) interference were evaluated using clinical specimens from inflammatory bowel disease patients (N = 237).

RESULTS.—

Analytical run time and sample preparation time were 5 minutes per sample and 3 hours per batch, respectively. Analytical measurement interval and limit of detection were 0.50 to 50.0 μg/mL (R2 = 0.998) and 0.25 μg/mL, respectively. The intraday and interday imprecision percentage coefficients of variation were less than 6.1%. Accuracy was 94.2% to 98.7%. No significant ion suppression or carryover was observed. Infliximab concentrations measured by LC-MS/MS showed good agreement with those measured by Remsima Monitor (mean percentage difference, 5.7%; 95% CI, -1.2% to 12.6%) but were markedly lower than those measured by IDKmonitor (-32.6%; -35.8% to -29.4%), demonstrating significant bias between ELISAs. Although a good agreement between LC-MS/MS and ELISA was observed for ADA-negative samples (-3.5%; -12.8% to 5.9%), a significant bias was observed for ADA-positive samples (13.6%; 1.7% to 25.6%).

CONCLUSIONS.—

This simple, fast, and affordable LC-MS/MS method for infliximab quantitation could improve standardization of infliximab quantitation and optimization of infliximab use in patients with high-titer ADA.

Long-term outcomes of liver transplantation for biliary atresia and results of policy changes: over 20 years of follow-up experience

Objective

Biliary atresia (BA) patients develop chronic liver disease after the Kasai operation and are eventually indicated for liver transplantation (LT). The purposes of this study were to analyze long-term outcomes after LT and risk factors that affect complications to reduce graft failure.

Study design

Overall, 145 pediatric patients who underwent LT between June 1996 and June 2020 after a diagnosis of BA were included. We performed a retrospective analysis of medical records and evaluated patient and graft survival, cumulative incidence of complications, risk factors, and the results of policy changes.

Results

Patient and graft survival rates in over 20 years were 95.8% and 91.0%, respectively. Post-transplantation lymphoproliferative disease was frequently observed in the early period of immunosuppression within the first 1-2 years after LT. The incidence of cholangitis and rejection steadily increased over time. Weight-to-portal vein size was evaluated as a risk factor for cholangitis and bile duct strictures (OR = 12.82, p = 0.006 and OR = 16.54, p = 0.015, respectively). When evaluated using 2013 as a reference point, the split graft indication was expanded and the group that received LT after 2013 had a significantly lower survival over time compared with that of the group that received LT before 2013 (p = 0.006).

Conclusion

This study revealed time differences in prevalence of complications. The evaluation of weight-to-duct or vessel size is a more important factor in considering complications than the graft-to-recipient weight ratio. Survival outcomes may have been altered by a policy change that affects the donor type ratio in transplantation.

Impact of the histologic grade of acute gastrointestinal graft-versus-host disease on outcomes in pediatric patients treated with allogeneic hematopoietic stem cell transplantation

Introduction

Acute gastrointestinal graft-versus-host disease (GVHD) is a common life-threatening complication after hematopoietic stem cell transplantation (HCT). We aimed to investigate outcomes according to the clinical, endoscopic, and histologic severity of gastrointestinal GVHD in pediatric patients treated with allogeneic HCT.

Methods

This retrospective cohort study included pediatric patients who underwent sufficient endoscopic and histopathologic evaluation for clinically suspected acute gastrointestinal GVHD between 2010 and 2020.

Results

Fifty-one patients were included (male proportion, 68.6% [35/51]; median age at HCT, 6.4 years). When the patients were classified according to the histologic severity of gastrointestinal GVHD, the severe group had an earlier onset of GVHD symptoms and a higher proportion of patients with severe clinical gastrointestinal GVHD than the mild-to-moderate and "absent" groups. In Cox proportional hazards regression analysis, the groups with more severe clinical and histologic gastrointestinal GVHD showed a higher risk of non-relapse mortality (NRM). The 5-year overall survival (OS) rates were 58.3 and 36.4% in the mild-to-moderate and histologic gastrointestinal GVHD groups, respectively (p = 0.0384). Patients with higher clinical and histologic grades of gastrointestinal GVHD showed higher cumulative incidence of NRM.

Discussion

Our results demonstrated that histologic severity of gastrointestinal GVHD is a relevant factor affecting OS and NRM, and patients with mild-to-moderate or severe histologic gastrointestinal GVHD have worse outcomes than patients without histologic GVHD. These findings support the importance of assessing the histologic grade in the diagnostic evaluation of patients with clinical gastrointestinal GVHD.

Free antibodies-to-infliximab are biomarker for predicting the effect of dose intensification in pediatric Crohn's disease patients with secondary loss of response

Background

Immunogenicity to antitumor necrosis factor alpha agents, such as infliximab (IFX), may lead to therapeutic failure.

Objectives

This study evaluated the relationship between free and total antibodies-to-infliximab (ATIs), trough levels (TLs) of IFX, and the response to dose intensification.

Design

We performed a prospective, observational study including pediatric patients with Crohn's disease (CD) receiving IFX maintenance therapy without dose intensification.

Methods

We compared clinical and laboratory outcomes according to the presence of free and total ATIs. Factors associated with response to IFX dose intensification were investigated by analyzing IFX TLs and free and total ATIs.

Results

Of the 98 patients, 9 patients had detectable free ATIs and 38 patients had total ATIs. Patients with free ATIs had significantly lower TLs (0.7 versus 5.1 µg/mL, p < 0.001) than patients without free ATIs. However, there was no difference in the IFX TLs according to the presence of total ATIs (p = 0.2523). Analysis of the 38 samples with total ATIs showed that response to dose intensification was significantly lower in patients with free ATIs than those without free ATIs (22.2% versus 65.5%, p < 0.001). In addition, free ATIs were the only factor with poor response to dose intensification [odds ratio (OR): 14.15, 95% confidence interval (CI): 1.31-151.97, p = 0.0140]. According to the receiver operating characteristic analysis, the optimal cutoff level indicating non-response to IFX dose intensification was 30.0 AU/mL for free ATIs concentration (area under curve, 0.792; 95% CI: 0.590-0.942; sensitivity, 60.0%; specificity, 96.7%; p = 0.0241).

Conclusion

Free ATIs, but not total ATIs, have a negative impact on the course of CD. Free ATIs are potential reliable biomarker for predicting the effect of dose intensification in patients with loss of response to IFX. Future studies based on serial and proactive therapeutic drug monitoring are required in the future.

Dual Biological Therapy for Ulcerative Colitis with Intractable Pyoderma Gangrenosum

Pyoderma gangrenosum is one of the dermatological extra-intestinal manifestations of ulcerative colitis (UC). We report a case of a 26-year-old male patient suffering from relapsed UC with a newly developed pyoderma gangrenosum. His skin and intestinal symptoms were intractable to treatment with steroids, immunosuppressants, or a single biological agent such as infliximab, golimumab, or vedolizumab. For the first time in Korea, we report a successful treatment experience of pyoderma gangrenosum in UC using dual biological agents, vedolizumab and infliximab. We strategically targeted each of the intestinal and skin symptoms, with a specific biological agent based on the drug's mechanism of action.

Increased monocyte abundance as a marker for relapse after discontinuation of biologics in inflammatory bowel disease with deep remission

Monocytes are involved in the upstream inflammatory process in the immune reaction in inflammatory bowel disease (IBD). Patients with IBD who discontinued biologics have been found to relapse, even after checking for deep remission. This study investigated whether monocytes could act as a predictor of relapse in patients who experienced relapse after the discontinuation of biologics. To this end, pediatric patients (<19 years old, n = 727) diagnosed with IBD from January 2003 to December 2021 were retrospectively reviewed. Clinical features, monocytes, and disease activity at the time of discontinuing biologics were evaluated by dividing patients into a relapsed group and a non-relapsed group after discontinuing biologics. The percentage of monocytes (8.65% vs. 6.42%, P < 0.001), the absolute monocyte count (614.79 cells/μL vs. 381.70 cells/μL, P < 0.001), and the monocyte/polymorphonuclear leukocyte (PMN) ratio (0.18 vs. 0.11, P < 0.001) at the time of discontinuation were significantly higher in patients who experienced relapse. As a result of multivariate analysis, the monocyte percentage (odds ratio: 2.012, P < 0.001) and monocyte/PMN ratio (odds ratio: 4.320E+14, P = 0.002) were evaluated as risk factors for relapse. Diagnostic capability was confirmed using area under operating characteristic curve (0.782) of the monocyte percentage for assessing the relapse within 6 months with cutoff value of 8.15% (P < 0.001). The findings presented in this study indicate that the patients with high monocyte counts experienced relapse after the discontinuation of biologics. A monocyte percentage of over 8.15% in the blood at the time of discontinuation was found to be associated with a high probability of relapse within 6 months, even in deep remission.

Transmural healing evaluated by magnetic resonance enterography in paediatric patients with Crohn's disease receiving maintenance treatment with biologics

BACKGROUND

The optimal treatment goal in Crohn's disease (CD) is endoscopic healing (EH). However, transmural healing (TH) facilitated by the development and increasing performance of magnetic resonance enterography (MRE) is emerging as a potential treatment goal.

AIMS

To assess TH rates after 1 year of treatment by MRE and its relationship with EH in paediatric patients with CD receiving anti-tumour necrosis factor (TNF) agents, and to investigate factors associated with TH after 1 year of treatment.

METHODS

This multi-centre, prospective, observational study included Korean paediatric patients with luminal CD diagnosed at age < 19 years who were naïve to anti-TNF treatment. They simultaneously underwent ileocolonoscopy and MRE at baseline and after 1 year of treatment with biologics.

RESULTS

We included 116 patients. At 1 year, EH and TH were achieved in 59.5% (69/116) and 38.8% (45/116) of the patients, respectively. Both EH and TH was observed in 35.3% (41/116), EH without TH in 24.1% (28/116), TH without EH in 3.4% (4/116), and neither EH nor TH in 37.1% (43/116). Moreover, 59.4% (41/69) of patients who achieved EH at 1 year exhibited TH, and 91.1% (41/45) of patients who achieved TH exhibited EH. Baseline MaRIA score was associated with TH according to a multivariate analysis (OR 0.97, 95% CI 0.95-0.99, p = 0.023).

CONCLUSION

TH is a more stringent goal than EH. Regular follow-up evaluation of transmural status, and efforts to achieve TH, may alter the natural course of CD in the era of treat-to-target.

Vedolizumab Is Safe and Efficacious for the Treatment of Pediatric-Onset Inflammatory Bowel Disease Patients Who Fail a Primary Biologic Agent

BACKGROUND

Vedolizumab (VDZ) is currently licensed for use in adults for the treatment of inflammatory bowel disease (IBD). We aimed to investigate the clinical course of pediatric-onset IBD following treatment with VDZ as more than a secondary biologic agent. We also evaluated factors associated with secondary loss of response (LOR) and durability of VDZ treatment.

METHODS

Pediatric-onset IBD patients diagnosed at an age younger than 18 years who had received VDZ as more than a secondary biologic agent were included in this retrospective observational study conducted at the Department of Pediatrics of two centers in Korea. Comparative analysis was conducted between groups divided according to the development of secondary LOR during VDZ treatment.

RESULTS

A total of 24 patients comprising 10 patients with Crohn's disease and 14 with ulcerative colitis were included. Of these, 19 were male and 5 were female. The mean age at diagnosis was 14.6 ± 2.5 years. The mean age at initiation of VDZ was 20.5 ± 2.8 years. Nine patients (37.5%) had received two or more biologic agents before starting VDZ. During a median of 0.9 years follow-up from VDZ initiation, 9 patients (37.5%) experienced LOR requiring interval shortening and 4 patients (16.7%) were changed to a different biologic agent. According to multivariate Cox proportional hazard regression analysis, administration of two or more biologic agents before VDZ treatment was the only factor positively associated with LOR (hazard ratio [HR], 5.6; 95% confidence interval [CI], 1.026-30.56; P = 0.047), while LOR was the only factor negatively associated with VDZ durability (HR, 0.003; 95% CI, 0.00-0.08; P = 0.010). No adverse events were observed during treatment with VDZ.

CONCLUSION

VDZ is safe and efficacious for the treatment of pediatric-onset IBD patients failing a primary biologic agent. The durability of VDZ may be enhanced by introducing VDZ earlier in the disease course. Further prospective studies in children are required in the future to validate these findings.

Comparison between Pediatric Crohn's Disease and Ulcerative Colitis at Diagnosis in Korea: Results from a Multicenter, Registry-Based, Inception Cohort Study

Background/Aims

We aimed to compare the differences in pediatric Crohn's disease (CD) and ulcerative colitis (UC) at diagnosis in Korea.

Methods

This was a multicenter, registry-based, inception cohort study conducted at five centers in Korea between 2013 and 2017. Baseline demographics, clinical characteristics, and results from laboratory, endoscopic, radiologic examinations were compared between pediatric CD and UC patients who were <19 years old at diagnosis.

Results

A total 307 patients were included (227 CD [73.9%] and 80 UC [26.1%]). The male to female ratio was 2.49:1 for CD, and 1.49:1 for UC (p=0.019). Median age at diagnosis was 14.4 years (interquartile range, 12.4 to 16.2) for CD, and 14.4 years (interquartile range, 11.7 to 16.5) for UC (p=0.962). Hematochezia was the only dominant symptom in UC patients compared to CD patients (86.2% vs 30.8%, p<0.001). White blood cell counts, platelet counts, erythrocyte sedimentation rate, and C-reactive protein levels were significantly higher, and serum albumin level was significantly lower in CD patients than in UC patient. Anti-Saccharomyces cerevisiae antibody was positive in 44.5% and 16.2% of CD and UC patients, respectively (p<0.001), and antineutrophil cytoplasmic antibody was positive in 15.0% and 58.8% of CD and UC patients, respectively (p<0.001). Terminal ileal involvement was prominent in CD, while rectal involvement was more prominent in UC. Small bowel involvement and perianal perforating diseases were also more prominent in CD.

Conclusions

This is the first a multicenter study in Korea to compare the differences between pediatric CD and UC at diagnosis in Korea. A large-scale, national study is expected to better clarify these findings in the future.

Comparison of Ustekinumab Trough Concentrations Measured by 2 ELISA Kits and Evaluation of Clinical Response in Crohn's Disease

BACKGROUND

Ustekinumab is a recently introduced biological agent for the treatment of Crohn's disease. The clinical use of the trough concentration of ustekinumab is not as standardized as that of infliximab. The authors aimed to introduce a measurement method and the results of trough concentrations of ustekinumab in clinical applications.

METHODS

Thirty-two blood samples from 10 young adult patients diagnosed with Crohn's disease were analyzed. During the maintenance treatment, injection intervals were shortened from 12 weeks to 8 weeks in 4 patients who exhibited a loss of response. Ustekinumab trough concentrations were measured using 2 commercial ELISA kits, kit A and kit B.

RESULTS

The median trough concentrations measured with kits A and B were 0.26 and 0.38 mcg/mL, respectively. In the case of kit A, low trough concentrations were undetected on many occasions and measured as zero, whereas kit B displayed their relative values even at low concentrations. Poor clinical parameters, elevated erythrocyte sedimentation rate, C-reactive protein, and calprotectin levels were significantly correlated with lower trough concentrations ( P < 0.05). The area under the receiver operating characteristics curve of kit B (0.921) was greater than that of kit A (0.744). The optimal cutoff values for prediction clinical responses were 0.17 and 0.41 mcg/mL for kit A and kit B, respectively.

CONCLUSIONS

The trough concentration of ustekinumab measured by the 2 ELISA kits correlated with laboratory results that indicated the activity of Crohn's disease. Furthermore, kit B detected even minute changes in trough concentrations.

How has the disease course of pediatric ulcerative colitis changed throughout the biologics era? A comparison with the IBSEN study

BACKGROUND

In Korea, infliximab was approved for use in children with ulcerative colitis (UC) in October 2012.

AIM

To compare the clinical course of UC before and after the introduction of biological agents, and to compare with the IBSEN study.

METHODS

Patients under 18 years of age, who were diagnosed with UC and followed from January 2003 to October 2020, were included in the study. Group A (n = 48) was followed for at least 2 years between January 2003 and October 2012, and Group B (n = 62) was followed for at least 2 years between November 2012 and October 2020. We compared endoscopic remission, drug composition, relapse rate, steroid-free period, and the quality of life of each group. We plotted the clinical course of the included patients using the pediatric UC activity index score, and compared our patients with those in the IBSEN study.

RESULTS

After 2 years of treatment, colonoscopy evaluation revealed different outcomes in the two treatment groups. Remission was confirmed in 14 patients (29.2%) of Group A, and in 31 patients (50.0%) of Group B (P < 0.012). The median cumulative corticosteroid-free period was 3.0 years in Group A and 4.4 years in Group B. Steroid-free period of Group B was significantly longer than that of Group A (P < 0.001). There was a statistically significant difference between the two groups in evaluation of the relapse rate during the observation period (P < 0.001). The plotted clinical course graphs of Group A showed similar proportions to the graphs in the IBSEN study. However, in Group B, the proportion of patients corresponding to curve 1 (remission or mild severity after initial high activity) was high at 76% (47/62).

CONCLUSION

The incidence of relapse has decreased and the steroid-free period has increased after the introduction of the biological agent. The clinical course also showed a different pattern from that of IBSEN study. The active use of biological agents may change the long-term disease course in moderate to severe pediatric UC.

NUDT15 intermediate metabolisers are associated with lower loss of response in paediatric Crohn's disease patients treated by combination treatment with infliximab and azathioprine

BACKGROUND

NUDT15 polymorphisms are associated with leukopenia during treatment with thiopurines. However, data regarding its effect on treatment outcomes are scarce.

AIMS

To investigate the outcomes between NUDT15 normal and intermediate metabolisers in paediatric patients with Crohn's disease (CD) treated with a combination therapy of infliximab (IFX) and azathioprine (AZA).

METHODS

In this retrospective observational study, 143 patients categorised into the NUDT15 normal and intermediate metaboliser groups were compared based on clinical remission (CR), biochemical remission (BR), mucosal healing (MH) at 1 year treatment, IFX trough levels (TLs), antibodies to IFX (ATIs), 6-thioguanine nucleotide (6-TGN) levels, loss of response (LOR) and IFX durability.

RESULTS

No significant differences were observed between the groups in CR, BR, MH at 1 year, whereas IFX TLs and ATIs and 6-TGN levels were comparable. However, LOR (6.5% vs 27.7%, P = 0.025) was significantly lower and IFX durability significantly higher (96.8% vs 80.4% P = 0.027) in the intermediate group. Multivariable Cox proportional hazard regression analysis showed that ATI positivity (hazard ratio (HR): 4.76, 95% CI: 2.25-10.07, P < 0.001) and the NUDT15 metaboliser group was associated with LOR (HR: 0.18, 95% CI: 0.04-0.76, P = 0.019). The Kaplan-Meier survival curves showed that the LOR-free survival rate was significantly lower in normal metabolisers (log-rank test P = 0.009).

CONCLUSION

NUDT15 intermediate metabolisers were associated with lower LOR in paediatric patients with CD treated with IFX and AZA combination therapy. This finding may partially explain the longer durability of IFX in Korean children than their counterparts in Western countries.

Discontinuation of Azathioprine could be considered in pediatric patients with Crohn's disease who have sustained clinical and deep remission

Few studies have demonstrated treatment strategies about the duration and cessation of medications in patients with Crohn's disease (CD). We investigated factors affecting clinical relapse after infliximab (IFX) or azathioprine (AZA) withdrawal in pediatric patients with CD on combination therapy. Pediatric patients with moderate-to-severe CD receiving combination therapy were analyzed retrospectively and factors associated with clinical relapse were investigated. Discontinuation of IFX or AZA was performed in patients who sustained clinical remission (CR) for at least two years and achieved deep remission. A total of 75 patients were included. Forty-four patients (58.7%) continued with combination therapy and 31 patients (41.3%) discontinued AZA or IFX (AZA withdrawal 10, IFX withdrawal 15, both withdrawal 6). Cox proportional-hazards regression and statistical internal validation identified three factors associated with clinical relapse: IFX cessation (hazard ratio; HR 2.982, P = 0.0081), IFX TLs during maintenance therapy (HR 0.581, P = 0.003), 6-thioguanine nucleotide (6-TGN) level (HR 0.978, P < 0.001). However, AZA cessation was not associated with clinical relapse (P = 0.9021). Even when applied in pediatric patients who met stringent criteria, IFX cessation increased the relapse risk. However, withdrawal of AZA could be contemplated in pediatric patients with CD who have sustained CR for at least 2 years and achieved deep remission.

Increased Demand for Therapeutic Drugs in Pediatric Ulcerative Colitis Patients With Extraintestinal Manifestations

BACKGROUND

Ulcerative colitis (UC) is a systemic inflammatory disease with a gut predominance, which may involve other organs. The presence of extraintestinal manifestation (EIM) is an important symptom for clinicians as it alters the treatment decisions. In this study, we aimed to evaluate the initial clinical presentation and disease severity of pediatric UC patients with EIMs.

METHODS

One hundred forty-two patients under the age of 18 years who were diagnosed with UC from January 2003 to November 2021 were included in this study. Forty-seven patients with confirmed EIMs and 95 patients without EIMs were divided into two groups and their differences were analyzed.

RESULTS

The most common EIM was peripheral arthritis. The disease extent at the time of diagnosis shows a higher rate of pancolitis in the EIM-positive group (65.9%) than that of the EIM-negative group (33.7%) (p < 0.001). More than 90% of EIM-positive patients had moderate to severe disease activity on the Mayo endoscopic subscore. In the EIM-positive group, the cumulative use of systemic steroids, immunosuppressants, and biological agents from diagnosis to 1 year follow-up were significantly higher than those of the EIM-negative group (p = 0.009, 0.001, and < 0.001, respectively). About 80% of patients in the EIM-negative group reached remission, but only about 50% of the EIM-positive patients reached remission (p = 0.005). The relapse occurred more frequently in the EIM-positive group than in the EIM-negative group with statistical significance (p < 0.001).

CONCLUSION

Pediatric UC with EIMs had higher disease severity and often manifested upper gastrointestinal tract involvement. Despite EIMs treatment, the occurrence of new EIMs was observed repeatedly. Cumulative drug demand (steroids, immunosuppressants, and biological agents) for the treatment increased steadily over time, and frequent relapses occurred despite the combinatory use of therapeutic drugs.

Stratification by Non-invasive Biomarkers of Non-alcoholic Fatty Liver Disease in Children

BACKGROUND

The spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from isolated hepatic steatosis to non-alcoholic steatohepatitis to fibrosis. We aimed to introduce useful biomarkers released during liver inflammation and fibrogenesis that are easy to use in outpatient clinic and adjust to children to evaluate each NAFLD stage without biopsy.

METHODS

This prospective study included 60 patients aged under 19 years whose alanine aminotransferase (ALT) levels were elevated from March 2021. All patients were proven to have NAFLD by ultrasonography and laboratory work-up to exclude other causes of hepatitis. Fibroscan and additional laboratory tests for biomarkers [procollagen type1 amino-terminal propeptide (P1NP), osteocalcin, interleukin-6 (IL-6), and Mac-2 binding protein glycosylated isomer (M2BPGi)] were performed. Fibroscan-AST (FAST) score was used for the comparison of steatohepatitis and liver stiffness measurement (kPa) was used for the comparison of advanced fibrosis.

RESULTS

The biomarker that showed a significant difference between the FAST-positive and negative groups was the P1NP/osteocalcin ratio with a p-value of 0.008. The area under receiver operating characteristic (AUROC) of P1NP/osteocalcin ratio^*ALT values (values obtained through multivariate analysis) was 0.939 with the cut-off value of 305.38. The biomarkers that showed a significant difference between the LSM-positive and negative groups were IL-6 and M2BPGi with a p-values of 0.005 and <0.001. AUROC of IL-6 ^*AST values (values obtained through multivariate analysis) was 0.821 with the cut-off value of 228.15. M2BPGi showed a significant linear relationship with LSM in Pearson correlation analysis (Pearson correlation coefficient = 0.382; p = 0.003). The diagnostic capability of M2BPGi to evaluate advanced fibrosis showed an acceptable result (AUROC = 0.742; p = 0.022).

CONCLUSIONS

Non-invasive biomarkers can be used to predict each stage of NAFLD in children. The measurements of P1NP, IL-6 or M2BPGi along with the basic chemistry tests would help determine the stage of NAFLD they correspond to at the time of initial diagnosis and predict responsiveness after the treatment.

Anti-Saccharomyces cerevisiae Antibody in Pediatric Crohn's Disease Patients without Mucosal Healing Is a Useful Marker of Mucosal Damage

Background/Aims

We evaluated whether anti-Saccharomyces cerevisiae antibody (ASCA) titers are associated with diagnostic findings, disease activity, Paris classification phenotypes, and persistence after infliximab (IFX) treatment in children with Crohn’s disease (CD). We also investigated the role of ASCA as a predictor of mucosal healing (MH) and clinical remission (CR).

Methods

This study included 61 CD patients aged 19 years or younger who were diagnosed and treated between September 2010 and January 2019 and followed for at least 1 year. ASCA was regularly measured at the diagnosis of CD and at least 1 year after IFX therapy.

Results

The average follow-up period was 3.8±3.4 years (range, 1.0 to 7.2 years). Regression analysis showed that the ASCA titer was the only factor associated with Simple Endoscopic Score for Crohn's Disease (SES-CD) or CR among all the parameters. In patients who had achieved MH (SES-CD=0), ASCA immunoglobulin G (IgG) was not associated with MH, but in patients without MH, ASCA IgG was associated with SES-CD (p=0.005) and CR (p<0.001). The cutoff value of ASCA IgG in patients with CR was 21.8 units. However, there was no difference in the relapse rate between the ASCA IgG-positive and -negative groups during the follow-up period.

Conclusions

In patients who have not achieved MH, ASCA IgG is closely related to mucosal damage and CR. Unlike Western studies, ASCA IgG may be more helpful in predicting prognosis than immunoglobulin A in Korean patients, but it is not an appropriate indicator to predict the relapse of CD. (Gut Liver 2021;15-770)

Preparing for medical education after the COVID-19 pandemic: insightology in medicine

It is necessary to reflect on the question, "How to prepare for medical education after coronavirus disease 2019 (COVID-19)?" Although we are preparing for the era of Education 4.0 in line with the 4th industrial revolution of artificial intelligence and big data, most measures are focused on the methodologies of transferring knowledge; essential innovation is not being addressed. What is fundamentally needed in medicine is insightful intelligence that can see the invisible. We should not create doctors who only prescribe antispasmodics for abdominal pain, or antiemetic drugs for vomiting. Good clinical reasoning is not based on knowledge alone. Insightology in medicine is based on experience through Bayesian reasoning and imagination through the theory of mind. This refers to diagnosis of the whole, greater than the sum of its parts, by looking at the invisible using the Gestalt strategy. Identifying the missing process that links symptoms is essential. This missing process can be described in one word: context. An accurate diagnosis is possible only by understanding context, which can be done by standing in someone else's shoes. From the viewpoint of medicine, Education 4.0 is worrisome because people are still clinging to methodology. The subject we should focus on is "human", not "artificial" intelligence. We should first advance the "insightology in medicine" as a new paradigm, which is the "essence" that will never change even when rare "phenomena" such as the COVID-19 outbreak occur. For this reason, we should focus on teaching insightology in medicine, rather than teaching medical knowledge.

Needs for Increased Awareness of Gastrointestinal Manifestations in Patients With Human Inborn Errors of Immunity

The gastrointestinal (GI) tract is frequently affected by inborn errors of immunity (IEI), and GI manifestations can be present in IEI patients before a diagnosis is confirmed. We aimed to investigate clinical features, endoscopic and histopathologic findings in IEI patients. This was a retrospective cohort study conducted from 1995 to 2020. Eligible patients were diagnosed with IEI and had GI manifestations that were enough to require endoscopies. IEI was classified according to the International Union of Immunological Societies classification. Of 165 patients with IEI, 55 (33.3%) had GI manifestations, and 19 (11.5%) underwent endoscopy. Among those 19 patients, nine (47.4%) initially presented with GI manifestations. Thirteen patients (68.4%) were male, and the mean age of patients 11.5 ± 7.9 years (range, 0.6 – 26.6) when they were consulted and evaluated with endoscopy. The most common type of IEI with severe GI symptoms was “Disease of immune dysregulation” (31.6%) followed by “Phagocyte defects” (26.3%), according to the International Union of Immunological Societies classification criteria. Patients had variable GI symptoms such as chronic diarrhea (68.4%), hematochezia (36.8%), abdominal pain (31.6%), perianal disease (10.5%), and recurrent oral ulcers (10.5%). During the follow-up period, three patients developed GI tract neoplasms (early gastric carcinoma, mucosa associated lymphoid tissue lymphoma of colon, and colonic tubular adenoma, 15.8%), and 12 patients (63.2%) were diagnosed with inflammatory bowel disease (IBD)-like colitis. Investigating immunodeficiency in patients with atypical GI symptoms can provide an opportunity for correct diagnosis and appropriate disease-specific therapy. Gastroenterologists and immunologists should consider endoscopy when atypical GI manifestations appear in IEI patients to determine if IBD-like colitis or neoplasms including premalignant and malignant lesions have developed. Also, if physicians in various fields are better educated about IEI-specific complications, early diagnosis and disease-specific treatment for IEI will be made possible.

Infliximab Therapy for Children with Moderate to Severe Ulcerative Colitis: A Step-Up versus a Top-Down Strategy

PURPOSE

We aimed to investigate clinical outcomes between top-down (TD) and conventional step-up (SU) therapies in pediatric patients with moderate to severe ulcerative colitis (UC).

MATERIALS AND METHODS

All patients underwent clinical and endoscopic evaluation at diagnosis and 4 months and 1 year after treatment. Patients who started treatment with corticosteroid were grouped in the SU group, while those that initiated early infliximab (IFX) were grouped in the TD group. Among the SU group, patients who eventually changed to IFX treatment due to steroid resistance or dependency were included in the SU(R) group.

RESULTS

In total, 44 children with moderate to severe UC were included for analysis. Twenty-one patients were included in the SU group, 23 were included in the TD group, and 10 were enrolled in the SU(R) group. Relapse rates were 47.6% (10/21) in the SU group and 17.4% (4/23) in the TD group (p=0.033). Among relapsed patients, the durations from remission to relapse were 17.3 months (0.9-46.9) in the SU group and 24.3 months (1.8-44.9) in the TD group. There was no statistically significant difference in the sustained durations of remission after IFX administration between the SU(R) and TD groups [3.9 (1.4-6.3) and 2.3 (0.3-5.2) years, respectively (p>0.05)].

CONCLUSION

According to our study, early use of IFX without corticosteroid treatment for children with moderate to severe UC helps to lower relapse rates. We also found that IFX was a very effective treatment for pediatric UC, with a sustained duration of remission similar between TD and SU(R) groups.

Albumin-to-Globulin Ratio at 1 Year after Anti-Tumor Necrosis Factor α Therapy Can Serve as a Prognostic Biomarker in Pediatric Crohn's Disease Patients

Background/Aims

The efficacy of biologics for the treatment of Crohn's disease (CD) is affected by the drug concentrations. We aimed to evaluate the importance of albumin and globulin which are known to be associated with drug concentrations as prognostic biomarkers in CD.

Methods

In total, 121 pediatric patients with CD who had received anti-tumor necrosis factor (TNF)-α therapy were retrospectively examined between January 2010 and February 2019.

Results

Relapse was observed in 48.8% of patients (59/121). The level of calprotectin (odds ratio, 2.13; p=0.03) and the albumin-to-globulin ratio (AGR) at 1 year after anti-TNF-α therapy (odds ratio, 0.0002; p=0.003) were associated with relapse. The AGR at 1 year after anti-TNF-α therapy was the only factor associated with the time-to-relapse (hazard ratio, 0.02; p<0.001). The optimal AGR cutoff value for the prediction of relapse was 1.47 (area under the curve, 0.916; p<0.001). The median infliximab trough level (TL) was lower in patients with AGRs <1.47 than in those with AGRs ≥1.47. Anti-drug antibody (ADA) concentrations were negatively correlated with the AGR at 1 year of anti-TNF-α therapy (r=-0.413, p=0.032).

Conclusions

AGR can be used to predict relapse. Patients with AGRs <1.47 at 1 year after anti-TNF-α therapy are more likely to have low drug TLs and develop ADAs, which increase the possibility of relapse than those with AGRs ≥1.47. Therefore, if the AGR at 1 year after anti-TNF-α therapy is less than 1.47, clinicians should monitor disease activity, assess the TLs of the anti-TNF-α agents, test for ADAs and determine the appropriate therapeutic strategies.

[How Can We Do Transition Successfully from Pediatric to Adult Clinics in Inflammatory Bowel Disease?]

With the increasing incidence of pediatric inflammatory bowel disease (IBD) in children and its impact throughout life, transition care has become an important issue. In Korea, no guidelines have been proposed to support the transition from the pediatric clinic to the adult IBD clinic. This paper reviews the current issues related to IBD patient care during the transition from pediatrics to adults to identify the barriers and critical elements for a successful transition. Thus far, a multi-disciplinary pediatric/adult clinic or alternate visits between pediatric and adult health care providers is the best model for pediatric to adult IBD clinics. Self-reliance and independence of patients with pediatric IBD are also essential for a successful transition. In addition, the timing of the transition from a pediatric clinic to an adult IBD clinic should not be determined because the issue is not the chronological age but rather the individual maturity.