Strategies for overcoming anti-tumor necrosis factor drug antibodies in inflammatory bowel disease: Case series and review of literature

Reactive Immunomodulator Addition to Infliximab Monotherapy Restores Clinical Response in Inflammatory Bowel Disease: A Meta-Analysis

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) receiving infliximab (IFX) commonly experience immunogenic loss of response (LOR) by formation of anti-drug antibodies (ADAs). An immunomodulator (IMM) used in combination with initial IFX induction is known to reduce ADA development and improve clinical outcomes. We aimed to assess the impact of reactively adding an IMM to patients on IFX monotherapy.

METHODS

We conducted a retrospective cohort study and systematic review with meta-analysis of patients with IBD demonstrating immunologic LOR, with or without clinical LOR, that had an IMM (azathioprine, 6-mercaptopurine, or methotrexate) reactively added (reactive combination therapy; rCT) to combat elevated ADAs and raise IFX level. Data were extracted for pooled effect size estimation using random-effects models, and ADA and IFX trough levels were compared pre- and post-IMM initiation.

RESULTS

We identified 6 patients who received rCT due to rising ADA titers and low IFX levels. Median ADA titer decreased from 506 ng/mL (interquartile range (IQR) [416-750]) to 76.5 ng/mL (IQR [25.8-232]), an 85% decrease (p = 0.031). Median IFX trough increased from 0.4 µg/mL (IQR [0.4-0.48]) to 8.25 µg/mL (IQR [3.7-9.6]), a 20.6-fold increase (p = 0.038). Meta-analysis pooled effect size of 7 studies with 89 patients showed an 87% ADA titer reduction [95% confidence interval (CI) = 72-94%], 6.7-fold increased IFX trough (95% CI = 2.4-18.7), and 76% clinical remission rescue rate (95% CI = 59-93%).

CONCLUSIONS

These results suggest rCT is a valid rescue strategy in patients with immunogenic LOR to IFX to reduce ADA titers, restore therapeutic IFX levels, and recapture clinical remission of IBD.

Risk factors for development of anti-adalimumab antibodies in non-infectious uveitis

Purpose

To evaluate risk factors associated with development of anti-adalimumab antibodies (AAA) in patients with non-infectious uveitis treated with adalimumab.

Methods

A retrospective, cross-sectional, case-control study was done evaluating patients with non-infectious uveitis treated with adalimumab for at least 12 months and have undergone testing for AAA levels. Demographics, clinical characteristics, grading of ocular inflammation, and previous and concomitant immunomodulatory therapy were assessed. Univariate and multivariate analysis were done to estimate odds ratio (OR) with 95% confidence intervals for the various risk factors.

Results

A total of 31 patients were included in the analysis, in which 12 patients who tested positive (Group 1) were matched with 19 patients who tested negative for AAA (Group 2). The groups differed significantly in terms of sex (female) (91.7% vs 52.6%, p = 0.046), presence of systemic disease (91.7% vs 42.1%, p = 0.008), and presence of anterior chamber inflammation at baseline (100% vs 63.2%, p = 0.026). A history of interruption in anti-TNF therapy prior to starting or restarting adalimumab was found to have an increased odds for development of AAA (OR 16.89 [2.92, 107.11], p = 0.008), as well as flare-ups (reactivation of disease) during adalimumab therapy (OR 6.77 [1.80, 61.80], p = 0.027). Weekly dosing of adalimumab was shown to decrease odds of AAA development (OR 0.34 [0.02, 0.70], p = 0.040), while concomitant anti-metabolite therapy was not shown to be a statistically significant protective factor (OR 2.22 [0.50, 9.96], p = 0.148).

Conclusions

History of interruption in anti-TNF therapy and flare during adalimumab were associated with development of AAA, while weekly dosing of adalimumab was protective against AAA. Identification of those with higher risk of developing AAA may guide in clinical decision making to optimize management for these patients.

Immunogenicity and Loss of Effectiveness of Biologic Therapy for Inflammatory Bowel Disease Patients Due to Anti-Drug Antibody Development

Many patients with inflammatory bowel disease (IBD) experience a loss of effectiveness to biologic therapy (i.e., anti-TNF therapy, etc.). Therefore, in addition to the adverse effects of the treatment, these patients also face failure to achieve and maintain remission. Immunogenicity, the process of production of antibodies to biological agents, is fundamental to the evolution of loss of response to treatment in IBD patients. The presence of these antibodies in patients is linked to decreased serum drug levels and inhibited biological activity. However, immunogenicity rates exhibit significant variability across inflammatory disease states, immunoassay formats, and time periods. In this review, we aimed to elucidate the immunogenicity and immune mechanisms of antibody formation to biologics, the loss of therapy response, clinical results of biological treatment for IBD from systematic reviews and meta-analyses, as well as to summarize the most recent strategies for overcoming immunogenicity and approaches for managing treatment failure in IBD.

Anti-infliximab antibodies and low infliximab levels correlate with drug discontinuation in pediatric inflammatory bowel disease

BACKGROUND

Infliximab (IFX) use is limited by loss of response often due to the development of anti-IFX antibodies and low drug levels.

METHODS

We performed a single center prospective observational cohort study of pediatric and young adult subjects with inflammatory bowel disease (IBD) on IFX with over 3 years of follow-up. Infliximab levels (IFXL) and antibodies to infliximab (ATI) were measured throughout the study. Subjects were followed until IFX was discontinued.

RESULTS

We enrolled 219 subjects with IBD (184: Crohn's disease; 33: Ulcerative colitis; and 2 Indeterminant colitis; 84 female, median age 14.4 years, 37% on concomitant immunomodulator). Nine hundred and nineteen serum samples (mean 4.2 ± 2.1 per patient) were tested for IFXL and ATI. During the study, 31 (14%) subjects discontinued IFX. Sixty patients had ATI. Twenty-two of those 60 patients with ATI discontinued IFX; 14 of 31 patients who discontinued IFX had detectable ATI at study onset. The combination of ATI and IFXL < 5 µg/mL at study entry was associated with the highest risk of drug discontinuation (hazard ratios [HR] ATI 4.27 [p < 0.001] and IFXL < 5 µg/mL [HR]: 3.2 p = 0.001). Patients with IFXL 5-10 µg/mL had the lowest rate of discontinuation (6%). IFX dose escalation eliminated ATI in 21 of 60 subjects.

CONCLUSIONS

ATI is a strong predictor of needing to stop IFX use and inversely correlates with IFXL. Detection of ATI during therapeutic drug monitoring postinduction but also periodically during maintenance therapy identifies individuals who may benefit from IFX dose escalation and/or the addition of an immunomodulator, as these interventions may reduce or eliminate ATI.

Biologic Therapy in Inflammatory Bowel Disease - Results from a Single Tertiary Care Center in North Macedonia

Medical therapies used for Inflammatory Bowel Disease (IBD) include conventional (e.g. 5-aminosalicylates, steroids, immunomodulators) and biologic (e.g. inhibitors of tumor necrosis factor - alpha, integrin inhibitors, interleukin inhibitors) medications. Biologics, due to their high cost, were unfortunately not covered by the public health insurance system in North Macedonia until 2019 and, therefore, not widely utilized for our IBD patients. In 2019, the University Clinic of Gastroenterology and Hepatology in Skopje developed a biologic therapy supply, provided by the National Health Insurance Fund, making this therapy available for a larger number of patients. This report presents the initial results of our prospective, single tertiary-care center study on the effects of biologic therapy in patients with IBD in North Macedonia. The study is focused on the evaluation of clinical outcomes after anti-tumor necrosis factor alpha (anti TNF-alpha) therapy in IBD patients with prior inadequate response to conventional medications.

Dose Escalation Patterns of Advanced Therapies in Crohn's Disease and Ulcerative Colitis: A Systematic Literature Review

INTRODUCTION

Dose escalation is one of the treatment approaches studied and suggested in advanced therapies for Crohn's disease (CD) and ulcerative colitis (UC). This study aimed to identify and characterize the dosing escalation patterns of advanced therapies in CD and UC.

METHODS

Two systematic literature reviews (SLRs) were conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE®, Embase®, and Cochrane Library were searched for articles published between January 2011 and October 2021 and limited to non-interventional studies in English language. Congress and bibliographic searches were also conducted. Articles were screened by two independent researchers. Dose escalation patterns were described and summarized considering the regional regulatory label recommendation (in North America [NA] or outside of North America [ONA]).

RESULTS

Among 3190 CD and 2116 UC articles identified in the Ovid searches, 100 CD and 54 UC studies were included in the SLR, with more studies conducted ONA. Most studies reported an initial maintenance dose pattern aligned with the lower starting dose per local regulatory label; however, several ONA studies (n = 13 out of 14) reported ustekinumab every 8 weeks as starting maintenance pattern in CD. In ONA studies, the median within-guideline escalation rates in CD and UC were 43% in ustekinumab (CD only), 33% and 32% for vedolizumab; 29% and 39% for adalimumab; and 14% and 10% for infliximab. Evidence regarding dose escalation patterns for tofacitinib, certolizumab pegol, and golimumab was limited. Some dose escalation patterns outside of label recommendations were observed including ustekinumab every 8 weeks to every 4 weeks and vedolizumab every 8 weeks to every 6 weeks.

CONCLUSION

Dose escalation strategies are widely documented in the literature. The reported dose escalation patterns and escalation rates vary by region and by CD and UC. Most escalation patterns reported were aligned with regulatory recommendations while some reported more diverse or aggressive dose escalation.

PROSPERO REGISTRATION

CRD42021289251.

Therapeutic drug monitoring in inflammatory bowel disease: implementation, utilization, and barriers in clinical practice in Scandinavia

BACKGROUND AND AIMS

Therapeutic drug monitoring (TDM) may optimize biologic and thiopurine therapies in inflammatory bowel disease (IBD). The study aimed to investigate implementation and utilization of TDM in Scandinavia.

METHODS

A web-based questionnaire on the use of TDM was distributed to Scandinavian gastroenterologists via the national societies.

RESULTS

In total, 297 IBD physicians prescribing biologic therapies, equally distributed between community and university hospitals, were included (response rate 42%) (Norway 118 (40%), Denmark 86 (29%), Sweden 50 (17%), Finland 33 (11%), Iceland 10 (3%)). Overall, TDM was applied during biologic therapies by 87%, and for TNF-inhibitors >90%. Among the users, reactive and proactive TDM were utilized by 90% and 63%, respectively. Danish physicians were significantly less inclined to use TDM compared to other Scandinavian countries; (58% vs 98%); OR 0.03 [0.01-0.09], p < 0.001). Reactive TDM was commonly applied at primary (74%) and secondary (99%) treatment failure. Proactive TDM was used by 80% during maintenance therapy and 56% during induction and more commonly utilized in Norway (p < 0.001), and by physicians managing >10 IBD patients/week (p = 0.005). TDM scenarios were interpreted in accord with available evidence but with discrepancies for proactive TDM. The main barriers to TDM were lack of guidelines (51%) and time lag between sampling and results (49%). TDM of thiopurines was routinely used by 87%.

CONCLUSION

TDM of biologic and thiopurine therapies has been broadly implemented into clinical practice in Scandinavia. However, physicians call for TDM guidelines detailing indications and interpretations of test results along with improved test response times.

The incidence, clinical characteristics and serological characteristics of anti-tumor necrosis factor-induced lupus in patients with inflammatory bowel disease: A systematic review and meta-analysis

BACKGROUND

There are concerns regarding anti-TNF-induced lupus (ATIL) in patients with inflammatory bowel disease (IBD). We performed a systematic review and meta-analysis about the incidence, the clinical characteristics and serological characteristics of ATIL secondary to anti-TNF agents in IBD patients.

METHODS

Electronic databases were searched to identify relevant studies. Primary outcomes were the pooled ATIL incidence rates in IBD patients treated with anti-TNF agents. Secondary outcomes were the pooled clinical symptoms incidence rates, autoantibodies incidence rates and clinical resolution rates in IBD patients treated with anti-TNF agents.

RESULTS

Ten studies were included in this meta-analysis. The pooled ATIL incidence rate in IBD patients treated with anti-TNF-α agents was 2.5%. The pooled ATIL incidence rate in UC and CD patients treated with anti-TNF-α agents was 1.5% and 1.8%, respectively. The pooled ATIL incidence rate in IBD patients treated with IFX and ADA was 4.5% and 0.2%, respectively. The pooled arthritis, mucocutaneous symptom, myalgia and fatigue incidence rate in IBD patients treated with anti-TNF-α agents was 87.2%, 29.4%, 23.9% and 41.8%, respectively. The pooled ANA rate in IBD patients treated with anti-TNF-α agents was 97.3%. The pooled anti-dsDNA antibody rate in IBD patients treated with anti-TNF-α agents was 73.9%.

CONCLUSION

ATIL has a low prevalence in IBD patients treated with anti-TNF agents. ATIL occurs more frequently in CD patients than in UC patients. Arthritis, fatigue and mucocutaneous lesions were found to be common symptoms of ATIL. Patients with ATIL were more likely to develop ANA and anti-dsDNA.

Anti-adalimumab Antibodies in Patients with Non-infectious Ocular Inflammatory Disease: A Case Series

PURPOSE

To report the clinical course of patients with ocular inflammatory disease treated with adalimumab in whom anti-adalimumab antibodies (AAA) were detected.

METHODS

Single center case series.

RESULTS

Eight patients with initial response to adalimumab developed a disease flare associated with positive AAA testing after 5 to 76 months of therapy. Six patients were receiving no concurrent antimetabolite therapy at the time of AAA diagnosis and four had a temporary lapse in adalimumab therapy prior to AAA discovery. AAA resulted in undetectable drug levels in five of the seven patients for whom data were available, and adalimumab was discontinued in six of the eight patients. Of two patients continued on adalimumab, one maintained detectable serum adalimumab despite AAA and one had a low AAA titer.

CONCLUSIONS

For patients receiving adalimumab for ocular inflammatory disease, a disease flare in the setting of previously well-controlled disease should prompt consideration of AAA testing.

Short interruptions of TNF-inhibitor treatment can be associated with treatment failure in patients with immune-mediated diseases

INTRODUCTION

The prevalence of immune-mediated diseases has increased in the past decades and despite the use of biological treatments all patients do not achieve remission. The aim of this study was to characterise the reasons for short interruptions during treatment with two commonly used TNF-inhibitors infliximab and adalimumab and to analyse the possible effects of the interruptions on immunisation and switching the treatment.

MATERIAL AND METHODS

This case-control study was based on retrospective analyses of patient records and a questionnaire survey to clinicians. A total of 370 patients (194 immunised cases and 172 non-immunised controls, 4 excluded) were enrolled from eight hospitals around Finland. Eleven different diagnoses were represented, and the largest patient groups were those with inflammatory bowel or rheumatic diseases.

RESULTS

Treatment interruptions were associated with immunisation in patients using infliximab (p < .001) or adalimumab (p < .000001). Patients with treatment interruptions were more likely to have been treated with more than one biological agent compared to those without treatment interruptions. This was particularly prominent among patients with a rheumatic disease (p < .00001). The most frequent reason for a treatment interruption among the cases was an infection, whereas among the control patients it was remission. The median length of one interruption was one month (interquartile range 1-3 months).

CONCLUSION

Our results suggest that the interruptions of the treatment with TNF-inhibitors expose patients to immunisation and increase the need for drug switching. These findings stress the importance of careful judgement of the need for a short interruption in the biological treatment in clinical work, especially during non-severe infections.

Indicators of suboptimal response to anti-tumor necrosis factor therapy in patients from China with inflammatory bowel disease: results from the EXPLORE study

Background

Prevalence of inflammatory bowel disease (IBD) is increasing in China. The EXPLORE study evaluated the incidence and indicators of suboptimal responses to first-line anti-tumor necrosis factor (TNF) in patients with ulcerative colitis (UC) or Crohn’s disease (CD). We present results for the mainland China subgroup.

Methods

A retrospective chart review was performed in adults with IBD at 10 centers in mainland China who initiated anti-TNF therapy between 01 March 2010 and 01 March 2015. The cumulative incidence of suboptimal response to first-line anti-TNF therapy was assessed over 24 months using the Kaplan–Meier method. Indicators of suboptimal response were: dose escalation, discontinuation, augmentation with non-biologic therapy, or IBD-related surgery/hospitalization. At site initiation, a survey was conducted with participating physicians to identify barriers to anti-TNF use.

Results

Of 287 patients (72% male) examined, 16/35 (45.7%) with UC and 123/252 (48.8%) with CD experienced a suboptimal response to first-line anti-TNF therapy at any point during the observation period (median 27.6 and 40.0 months, respectively). At 1 and 2 years post anti-TNF initiation, the cumulative incidence of suboptimal response was 51.4% and 75.7% for UC and 45.4% and 57.0% for CD, respectively. Median time to first suboptimal response was 7.2 months for UC and 14.3 months for CD. The most frequent indicator of suboptimal response was discontinuation of anti-TNF therapy (9/16, 56.3%) for UC and IBD-related hospitalization for CD (69/123, 56.1%) followed by augmentation with non-biologic therapy for both cohorts (5/16, 31.3% for UC and 28/123, 22.8% for CD). Dose escalation was the least frequent indicator of suboptimal response to anti-TNF therapy (CD: 4/123, 3.3%; UC: not cited as an indicator). The cumulative incidence of suboptimal response within 4 months of first-line anti-TNF therapy (primary non-response) was over 30% in both cohorts. Financial reasons and reimbursement were identified by surveyed physicians as the most common barriers to prescribing an anti-TNF therapy.

Conclusions

Over one-half of patients with IBD are at risk of experiencing a suboptimal response to first-line anti-TNF therapy at 2 years post-initiation in China. This study highlights a substantial unmet need associated with anti-TNF therapies in China. (Clinicaltrials.gov identifier: NCT03090139).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02074-z.

Successful Drug Desensitization to Ustekinumab in a Patient with Crohn's Disease

Ustekinumab is a monoclonal antibody used as treatment for various inflammatory conditions. We present a pediatric patient with Crohn's disease who did not tolerate infliximab and was then changed to ustekinumab. He developed anaphylaxis to the medication after the second dose. A drug desensitization protocol was created by the allergy team leading to successful administration of both intravenous and then subcutaneous ustekinumab. As monoclonal agents become mainstays of therapy for inflammatory conditions, there are increased reports of allergic reactions. Prior reports and protocols of ustekinumab desensitization have not been reported. This case report highlights successful desensitization to ustekinumab as well as the importance of a multidisciplinary approach to addressing treatment needs of patients who develop life-threatening reactions to such medications.

Potential application of measuring serum infliximab levels in rheumatoid arthritis management: A retrospective study based on KURAMA cohort data

Infliximab (IFX) therapy has considerably improved the treatment of rheumatoid arthritis (RA). However, some patients still do not respond adequately to IFX therapy, or the efficacy of the treatment diminishes over time. Although previous studies have reported a relationship between serum IFX levels and therapeutic efficacy, the potential applications of IFX therapeutic drug monitoring (TDM) in clinical practice remain unclear. The purpose of this study was to investigate the potential applications of IFX TDM by analyzing a Japanese cohort database. Data were collected retrospectively from the Kyoto University Rheumatoid Arthritis Management Alliance cohort between January 1, 2011, and December 31, 2018. Serum IFX levels were measured using a liquid chromatography-tandem mass spectrometer. Out of the 311 RA patients that used IFX, 41 were eligible for the analysis. Serum IFX levels were significantly higher in responders than in non-responders. An optimal cut-off value was determined to be 0.32 μg/mL based on a receiver operating characteristic curve. At the IFX measurement point, a better therapeutic response was observed in the high IFX group (n = 32) than in the low IFX group (n = 9). Conversely, at the maximum effect point, when DAS28-ESR was the lowest between IFX introduction and measurement points, there were no differences in responder proportions between the low and high IFX groups. IFX primary ineffectiveness could be avoided with appropriate dose escalation without blood concentration measurement in clinical practice. In conclusion, IFX TDM could facilitate the identification of secondary non-responders and in turn, proper IFX use.

Immunogenicity of Tumor Necrosis Factor Antagonists and Effect of Dose Escalation on Anti-Drug Antibodies and Serum Drug Concentrations in Inflammatory Bowel Disease

BACKGROUND

Infliximab and adalimumab concentrations are associated with important outcomes in inflammatory bowel disease (IBD). Antibodies to infliximab (ATI) and adalimumab (ATA) are associated with reduced drug concentrations and worse outcomes. Because the efficacy of dose escalation to overcome antibodies is unclear, we assessed the impact of this strategy to overcome immunogenicity in IBD.

METHODS

Infliximab and adalimumab dosing, drug, and antibody concentrations were extracted from a database of patients with IBD having specimens collected for therapeutic drug monitoring. The primary outcome compared proportions with either infliximab ≥5 μg/mL or adalimumab ≥7.5 μg/mL and undetectable antibodies between dose-escalated and non-escalated patients. Area under the receiver operating characteristic curve analyses determined antibody concentrations below which dose escalation was associated with the primary outcome.

RESULTS

The study included 63,176 patients treated with infliximab and 46,429 patients treated with adalimumab. We detected ATI and ATA in 23.6% (n = 14,900) of patients treated with infliximab and 19.6% (n = 9101) of patients treated with adalimumab. In patients with ATI, infliximab dose escalation (n = 453) yielded higher proportions achieving the primary outcome (47.5% vs 30.9%; P < 0.001), greater drug concentration increases (5.9 μg/mL vs 0.2 μg/mL; P < 0.001), and ATI reductions (4.3 U/mL vs 1.9 U/mL; P = 0.002) compared to no escalation (n = 204). An ATI threshold of 8.55 U/mL was associated with achieving the primary outcome with dose escalation (area under the curve = 0.66). For patients with ATI ≤8.55 U/mL (n = 274), higher proportions (59.1% vs 29.6%; P < 0.001) achieved the primary outcome compared with those with ATI >8.55 U/mL (n = 179). No patients treated with adalimumab achieved the primary outcome (0/390), regardless of dose escalation (n = 87).

CONCLUSION

Dose escalation increased drug concentrations and eliminated antibodies with infliximab but not adalimumab. Initial ATI ≤8.55 U/mL was associated with increased efficacy of dose escalation using this assay.

A Machine Learning Model Accurately Predicts Ulcerative Colitis Activity at One Year in Patients Treated with Anti-Tumour Necrosis Factor α Agents

Background and objectives: The biological treatment is a promising therapeutic option for ulcerative colitis (UC) patients, being able to induce subclinical and long-term remission. However, the relatively high costs and the potential toxicity have led to intense debates over the most appropriate criteria for starting, stopping, and managing biologics in UC. Our aim was to build a machine learning (ML) model for predicting disease activity at one year in UC patients treated with anti-Tumour necrosis factor α agents as a useful tool to assist the clinician in the therapeutic decisions. Materials and Methods: Clinical and biological parameters and the endoscopic Mayo score were collected from 55 UC patients at the baseline and one year follow-up. A neural network model was built using the baseline endoscopic activity and four selected variables as inputs to predict whether a UC patient will have an active or inactive endoscopic disease at one year, under the same therapeutic regimen. Results: The classifier achieved an excellent performance predicting the disease activity at one year with an accuracy of 90% and area under curve (AUC) of 0.92 on the test set and an accuracy of 100% and an AUC of 1 on the validation set. Conclusions: Our proposed ML solution may prove to be a useful tool in assisting the clinicians’ decisions to increase the dose or switch to other biologic agents after the model’s validation on independent, external cohorts of patients.

Anti-TNF-induced lupus in patients with inflammatory bowel disease

Background and Aims

Anti‐Tumor Necrosis Factor (TNF)‐induced lupus (ATIL) is a distinct clinical entity, increasingly recognized in patients with inflammatory bowel disease treated with anti‐TNF therapy. Our aims were to evaluate the incidence and clinical and serological markers of ATIL in this population.

Methods

This observational cohort study reviewed 454 patient treatment courses with anti‐TNF therapy (300 infliximab and 154 adalimumab). A diagnosis of ATIL was based on the most widely accepted diagnostic criteria: (i) a temporal relationship between symptoms and anti‐TNF therapy and resolution of symptoms following cessation of the offending medication; (ii) at least one serologic American College of Rheumatology (ACR) criterion of Systemic Lupus Erythematosus (SLE); and (iii) at least one nonserological criterion such as arthritis, serositis, or rash. Clinical, demographic, and serological predictors were evaluated.

Results

The incidence rate of ATIL was 5.7% for infliximab and 0.6% for adalimumab, which are much higher than previously reported postmarketing estimates. The median duration to diagnosis following commencement of anti‐TNF therapy was 15 months (3–62 months). ATIL occurs more commonly patients that commence therapy at an older age (46.47 years ± 13.79 years vs. 38.85 years ± 14.75 years, P = 0.033).

Conclusions

ATIL is a significant complication of anti‐TNF therapy, affecting 1 in every 20 patients who commence infliximab. A panel of serological markers is useful to confirm the diagnosis and exclude other conditions that may mimic ATIL. Clinicians using anti‐TNF medications should counsel patients about this potential risk and monitor for clinical manifestations of lupus during routine follow up.

Protective Role of Coxsackie-Adenovirus Receptor in the Pathogenesis of Inflammatory Bowel Diseases

AIM

To investigate the role of Coxsackie-adenovirus receptor (CAR) in inflammatory bowel disease (IBD).

BACKGROUND

CAR, a type I transmembrane protein with functions in virus attachment, has been shown to be associated with epithelial tight junctions (TJs) and mediates cell adhesion, implying its potential roles in the pathogenesis of IBD.

METHODS AND MATERIALS

To determine the effect of CAR in IBD using QPCR and Western blotting to determine the expression of CAD in TNF-α induced NCM460 and SW480 cells and IBD tissues compared to control groups. Furthermore, TJs dysregulation, FITC-Dextran permeability assay, qRT-PCR, Western blot, and IF assessed the permeability in CAR overexpressed cells treated with TNF-α. HE, qRT-PCR, Western blot, and IHC assay were used to assess the CAR overexpressed cells whether they have the effect to cure DSS induced ulcerative colitis rat model in vivo.

RESULT

We found CAR levels in human colon cell lines are significantly downregulated under the treatment of tumor necrosis factor-alpha (TNF-α). Furthermore, overexpression of CAR markedly prevented TNF-α induced inflammatory response, TJs dysregulation, and permeability disruption (FITC-Dextran permeability assay) in cells. Consistent with these findings in vitro, we found that CAR overexpression could suppress gut inflammation, attenuate the downregulation of TJ protein ZO-1 and Occludin, and limit the induction of barrier permeability in a DSS induced ulcerative colitis rat model in vivo. Together, our findings strongly suggest that CAR could protect tight junctions and has an anti-inflammatory effect during the pathogenesis of IBD. Thus CAR may serve as a therapeutic target for the diagnosis and treatment of IBD.

Low-Dose Methotrexate Prevents Primary and Secondary Humoral Immune Responses and Induces Immune Tolerance to a Recombinant Immunotoxin

Recombinant immunotoxins (RITs) are chimeric proteins being developed for cancer treatment. They are composed of an Ab fragment that targets a cancer Ag and a cytotoxic portion of Pseudomonas exotoxin A. They are effective for patients with hematologic malignancies with defective immunity, but their efficacy against solid tumors is limited by anti-drug Ab (ADA) responses in immune-competent patients. Pre-existing Abs or immune memory owing to previous toxin exposure represent additional hurdles because they induce rapid and strong ADA responses. Here, we evaluated the efficacy of methotrexate (MTX) to prevent ADA formation against the mesothelin-targeting RIT LMB-100 in naive mice and in mice with pre-existing Abs. We found that low-dose MTX combined with LMB-100 completely suppressed the formation of ADAs in a dose- and frequency-dependent manner. Suppression of the immune response restored blood levels of LMB-100 and prevented its neutralization. Furthermore, combination of MTX with LMB-100 did not compromise the immune response against a second Ag given after stopping MTX, indicating specific immune tolerance. Adoptive transfer of splenocytes suppressed Ab responses to LMB-100 in recipient mice, indicating a durable immune tolerance. We conclude that combination of MTX and LMB-100 is effective at preventing immune responses in a durable, Ag-specific manner. We propose combining low-dose MTX in immune-competent cancer patients receiving RIT therapy to prevent immunogenicity. This approach could be applied to other immunogenic therapeutic agents and to proteins for which there is pre-existing immunity.