Immune checkpoint inhibitor-induced diarrhea/colitis: Endoscopic and pathologic findings

New strategies in the diagnosis and treatment of immune-checkpoint inhibitor-mediated colitis

Immune-checkpoint inhibitor-mediated colitis (IMC) is an increasingly recognized adverse event in cancer immunotherapy, particularly associated with immune checkpoint inhibitors (ICIs) such as anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed cell death protein-1 antibodies. As this revolutionary immunotherapy gains prominence in cancer treatment, understanding, diagnosing, and effectively managing IMC becomes paramount. IMC represents a unique challenge due to its immune-mediated nature and potential for severe complications. However, a precise picture of IMC pathophysiology is currently unavailable. Therefore, we aimed to summarize the existing data while acknowledging the need for further research. This comprehensive review explores the mechanisms underlying ICIs, gastrointestinal adverse effects, and, in particular, IMC's incidence, prevalence, and features. Our review also emphasizes the importance of recognizing IMC's distinct clinical and histopathological features to differentiate it from other forms of colitis. Furthermore, this paper highlights the urgent need for evolving diagnostic methods, therapeutic strategies, and a multidisciplinary approach to effectively manage IMC.

Pembrolizumab-Induced Colitis and Diarrhea in the Treatment of Sporadic Colorectal Cancer: A Case Report

Pembrolizumab is a programmed cell death receptor-1 (PD-1) blocking immune checkpoint inhibitor (ICI) that is a mainstay of cancer treatment. Pembrolizumab has a lower incidence of colitis and diarrhea compared to other ICIs. The current study presents the case of a 30-year-old female patient on pembrolizumab with stage IV colon cancer who presented with diarrhea (50 times a day) and symptoms of colitis. A computed tomography scan of the abdomen and pelvis suggested proctitis. Stool studies were negative for enteric pathogens, but stool white blood cell (WBC) was positive, and calprotectin was >10,000 ug/g. A colonoscopy showed pancolitis with small internal hemorrhoids. Histopathology showed cryptitis and crypt abscesses with mild focal architectural distortion, mucosal erosion/ulcer, and focal crypt atrophy from the cecum to the rectum. All ICIs were discontinued, and the patient was initially managed with IV fluids. The patient was subsequently started on methylprednisolone and loperamide after colonoscopy. The number of bowel movements decreased to six per day after the above management. The patient was then switched to oral prednisone and discharged with outpatient follow-up. This case reveals the importance of assessing immune-related adverse effects (irAEs) even though incidence rates associated with a specific ICI might be low.

The colitis may be microscopic, but the diarrhea is not: update on the treatment of microscopic colitis and immune checkpoint inhibitor colitis

PURPOSE OF REVIEW

Microscopic colitis is an inflammatory disease of the colon that presents as watery diarrhea with minimal to normal endoscopic changes on colonoscopy. It encompasses two common subtypes, lymphocytic colitis and collagenous colitis, which are both treated similarly.Immune checkpoint inhibitor colitis is among the most common immune-related adverse events. Endoscopic and histological findings range from normal colonic mucosa to inflammatory bowel like changes. This review article provides update in treatment and management of microscopic colitis and immune checkpoint inhibitor colitis (ICPi colitis).

RECENT FINDINGS

Recent studies on microscopic colitis have focused on the successful use of immunomodulators such as biologics for treatment of budesonide refractory microscopic colitis cases. Microscopic colitis does not confer an added risk for colorectal cancer.With the increasing usage of immunotherapy agents, immune checkpoint inhibitor colitis is becoming more common. ICPi colitis can be successfully managed with steroids, with treatment stepped up to biologics for moderate to severe cases or for mild cases that do not respond to steroids. Immunotherapy agents can be carefully re-introduced in mild cases, after treatment of ICPi colitis.

SUMMARY

Biologics can be used to treat budesonide refractory microscopic colitis. ICPi colitis can be managed with steroids and biologics in moderate to severe cases.

Focus on Immune Checkpoint Inhibitors-related Intestinal Inflammation: From Pathogenesis to Therapeutical Approach

Recently, antitumor immunotherapies have witnessed a breakthrough with the emergence of immune checkpoint inhibitors (ICIs) including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors. Unfortunately, the use of ICIs has also led to the advent of a novel class of adverse events that differ from those of classic chemotherapeutics and are more reminiscent of autoimmune diseases, the immune-related adverse events (IRAEs). Herein, we performed an insight of the main IRAEs associated with ICIs, focusing on gastroenterological IRAEs and specifically on checkpoint inhibitor colitis, which represents the most widely reported IRAE to date. We comprehensively dissected the current evidence regarding pathogenesis, diagnosis, and management of ICIs-induced colitis, touching upon also on innovative therapies.

Therapeutic effect of Yiyi Fuzi Baijiang formula on TNBS-induced ulcerative colitis via metabolism and Th17/Treg cell balance

ETHNOPHARMACOLOGICAL RELEVANCE

Yiyi Fuzi Baijiang formula (YFB) is a traditional Chinese medicine prescription composed of Coix seed, Radix Aconiti Lateralis and Patrinia villosa, which has been used to treat ulcerative colitis (UC) for thousands of years.

AIM OF THE STUDY

To investigate the therapeutic effect and metabolic analysis of YFB formula on UC in rats induced by 2,4,6-trinitro-benzene sulfonic acid (TNBS).

MATERIALS AND METHODS

Six main alkaloids in the YFB formula were determined by UPLC‒MS/MS. The rat UC model was induced by TNBS, and the therapeutic effect of YFB formula on UC was evaluated by disease activity index (DAI) score and hematoxylin-eosin (HE) staining. UPLC-QTRAP-MS metabolomics technology was used to screen potential biomarkers for YFB treatment of UC in combination with multivariate data statistics and further analyze related metabolic pathways. Western blotting was used to detect the protein levels of NLRP1, NLRP3, NLRC4, ASC, pro-caspase1 and Caspase-1 in rat liver tissues. ELISA and immunohistochemistry were used to detect the contents of interleukin (IL)-17A, IL-21, IL-22, IL-6, TNF-α, IL-1β and IL-18 in rat serum and liver tissues.

RESULTS

The DAI scores of the YFB groups were significantly reduced, and colon tissue injury was significantly improved (p < 0.01). The results of metabolomics analysis revealed 29 potential biomarkers in serum and 27 potential biomarkers in liver. YFB formula can treat UC by affecting glycerophospholipid metabolism, primary bile acid biosynthesis, glyoxylic acid and dicarboxylic acid metabolism, and arginine and proline metabolism. Compared with the model group, the contents of IL-17A, IL-21, IL-22, IL-6, TNF-α, IL-1β and IL-18 in the YFB groups were decreased in a dose-dependent manner (p < 0.01). Compared with those in the model group, the protein levels of NLRP1, NLRP3, NLRC4, ASC, pro-caspase1 and Caspase-1 in the YFB groups were significantly decreased in a dose-dependent manner (p < 0.01).

CONCLUSIONS

The therapeutic effect of YFB formula on UC rats was dose dependent, and the effect of the YFB (2.046 g/kg) group was close to that of the positive group. YFB formula has an anti-inflammatory effect on UC by regulating the balance of Th17/Treg cells in rats.

Characteristics and usefulness of transabdominal ultrasonography in immune-mediated colitis

BACKGROUND/AIMS

The usefulness of ultrasonography (US) in diseases of the gastrointestinal tract has been reported recently. This prospective study aimed to determine the features of US findings in immune-mediated colitis (IMC), an adverse event induced by immune checkpoint inhibitor, and examine the correlation between US findings, colonoscopy (CS) findings, and severity of colitis.

METHODS

We studied patients examined using CS and US upon suspicion of IMC in Hokkaido University Hospital between April 2018 and February 2021. Endoscopic findings of IMC were assessed using the Ulcerative Colitis Endoscopic Index of Severity (UCEIS). The severity of US findings in IMC was evaluated using US grade, which is the ultrasonographic grading scale in ulcerative colitis. Bowel wall thickness and the intensity of the color Doppler signal were also analyzed. Severity of colitis was evaluated using Common Terminology Criteria for Adverse Events (CTCAE) grade version 5.

RESULTS

Fourteen patients with IMC were enrolled. The US findings were bowel wall thickening, loss of stratification, ulceration and increased blood flow signal. The US grade was moderately correlated with the UCEIS (r=0.687, p=0.009) and CTCAE grade (r=0.628, p=0.035). Bowel wall thickness and UCEIS (r=0.628, p=0.020), as well as color Doppler signal grade and CTCAE grade (r=0.724, p=0.008), were significantly correlated.

CONCLUSIONS

US findings in IMC were mainly similar to those of ulcerative colitis, but there were some findings that were characteristic only of IMC. Significant correlation was found between US findings, CS findings, and severity of colitis. Hence, US could be useful for the evaluation of IMC.

A Case of Hepatocellular Carcinoma Successfully Resumed Atezolizumab and Bevacizumab After Associated Grade 3 Diarrhea and Grade 2 Colitis: Case Report and Literature Review

Systemic chemotherapy has shown a significant survival benefit in patients with hepatocellular carcinoma (HCC). However, it is associated with various immune-related adverse events (irAEs). We report a case with grade 3 diarrhea and grade 2 colitis following systemic chemotherapy, successfully treated with prednisolone. An 89-year-old man was incidentally detected with a 140-mm hypervascular intrahepatic nodule on contrast-enhanced computed tomography (CECT). Washout of the contrast medium was also detected, and protein induced by vitamin K deficiency or antagonists-II (PIVKA-II) was elevated. Since the Albumin-Bilirubin (ALBI) grade was 2a without any distant metastasis, transarterial chemoembolization (TACE) was performed to treat the HCC, but several intrahepatic nodules were seen in both lobes. Therefore, the patient was treated with lenvatinib for 1 year and 4 months. A complete response according to modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria was achieved in 2 months; however, multiple hypervascular nodules were detected again. Since the ALBI grade was 1, a second round of chemotherapy with atezolizumab and bevacizumab was initiated. Although a complete response was achieved, the therapy was discontinued due to grade 3 diarrhea and grade 2 colitis after the sixth course. Based on the stool analysis and culture, CECT, and colonoscopy, the diagnosis was atezolizumab-associated colitis. Diarrhea was controlled following the oral administration of 0.5 mg/kg/day of prednisolone, and atezolizumab-bevacizumab therapy was successfully reinitiated without recurrence of colitis. The management of irAEs is important for a significant survival benefit. Systemic chemotherapy with atezolizumab and bevacizumab can be resumed despite a grade 3 irAE due to atezolizumab.

The multifaceted roles of common gut microbiota in immune checkpoint inhibitor-mediated colitis: From mechanism to clinical application

With the arrival of the era of tumor immunotherapy, Immune Checkpoint Inhibitors have benefited countless tumor patients. However, the emergence of Immune-Related Adverse Events, especially Immune Checkpoint Inhibitor-Mediated Colitis (IMC), has become an important obstacle to immunotherapy. Therefore, it is very important to clarify the mechanism and influencing factors of IMC. The effect of gut microbiota on IMC is gradually becoming a research hotspot. Gut microbiota from different phyla can affect IMC by regulating innate and acquired immunity of tumor patients in various ways. In this review, we make a systematic and comprehensive introduction of the effect of gut microbiota on IMC. Through understanding the specific effects of gut microbiota on IMC, and then exploring the possibility of reducing IMC by regulating gut microbiota.

Mesalamine and cholestyramine for immune checkpoint inhibitor-mediated diarrhea and colitis

PURPOSE

Immune checkpoint inhibitors (ICI) are effective against various malignancies. However, adverse events including diarrhea and colitis can lead to significant morbidity and mortality. Recommendations for the management of ICI mediated diarrhea and colitis include steroids and biologics. Given their associated risks, this study evaluated the role of the non-immunosuppressive agents, mesalamine and or cholestyramine.

METHODS

This is a retrospective, descriptive, single-center study of adults who developed ICI diarrhea and colitis between 2010 and 2020 at MD Anderson Cancer Center. Clinical data and outcomes were compared between those treated with the non-immunosuppressive therapies mesalamine and/or cholestyramine alone versus those who received additional immunosuppression with steroids and biologics.

RESULTS

Our sample comprised 66 patients wherein, the mean age was 63 years, 71% were males, and 97% had stage III/IV cancers. Fourteen patients were treated successfully with non-immunosuppressive therapy. They had grade 1-3 diarrhea and 1-2 colitis with no difference in the rate of histologic colitis compared to those who received immunosuppressive therapy. They had less CTLA-4 inhibitor-based therapy (36% vs. 73%, p = 0.034), delayed onset of symptoms (159 vs. 64 days, p = 0.011), lower fecal calprotectin levels (56 vs. 234, p = 0.012) and were more likely to resume ICI therapy (64% vs. 25%, p = 0.006).

CONCLUSION

Mesalamine and/or cholestyramine may be effective for mild ICI diarrhea and colitis among patients with delayed symptom onset with lower colonic inflammatory burden. Prospective studies randomizing patients with mild colitis between mesalamine/cholestyramine and immunosuppressive treatment are warranted to assess their efficacy and safety.

Immunotherapy-induced Colitis: A Comprehensive Review of Epidemiology, Clinical Presentation, Diagnostic Workup, and Management Plan

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of a variety of malignancies including advanced melanoma, non-small cell lung cancer, renal cell carcinoma, head and neck cancers among others. Since their introduction, there has been significant improvement in survival and prognosis in patients with advanced malignancies. Unfortunately, improved outcomes have come at a price of significant immune-related adverse events, with those of the gastrointestinal tract being the most common. Gastrointestinal immune-related adverse events frequently present as diarrhea and colitis, the severity of which can range from mild diarrhea to fulminant colitis with intestinal perforation. Currently, management of ICI-induced colitis is primarily guided by retrospective studies and expert opinion. A significant number of ICI-induced colitis responds to high-dose corticosteroids; however, some patients require further therapy with biologics. There is limited information on the factors which may predispose patients to ICI-induced colitis. Future research elucidating these risk factors along with development of a scoring system could allow for risk-stratification of patients before initiation of ICI therapy. Such a system may help clinicians and patients keep a high index of suspicion regarding ICI-induced colitis and could hopefully reduce the incidence of severe cases. Similarly, future studies should investigate protective factors against ICI-induced colitis, which could potentially allow more patients to safely benefit from ICI therapy.

Cutting Edge: Enhanced Antitumor Immunity in ST8Sia6 Knockout Mice

Inhibitory receptors have a critical role in the regulation of immunity. Siglecs are a family of primarily inhibitory receptors expressed by immune cells that recognize specific sialic acid modifications on cell surface glycans. Many tumors have increased sialic acid incorporation. Overexpression of the sialyltransferase ST8Sia6 on tumors led to altered immune responses and increased tumor growth. In this study, we examined the role of ST8Sia6 on immune cells in regulating antitumor immunity. ST8Sia6 knockout mice had an enhanced immune response to tumors. The loss of ST8Sia6 promoted an enhanced intratumoral activation of macrophages and dendritic cells, including upregulation of CD40. Intratumoral regulatory T cells exhibited a more inflammatory phenotype in ST8Sia6 knockout mice. Using adoptive transfer studies, the change in regulatory T cell phenotype was not cell intrinsic and depended on the loss of ST8Sia6 expression in APCs. Thus, ST8Sia6 generates ligands for Siglecs that dampen antitumor immunity.

Endoscopic and histopathologic features of Anti‐PD‐1‐related collagenous colitis

Objectives

Cancer patients treated with immune checkpoint inhibitors occasionally show persistent diarrhea accompanied by endoscopic features of ulcerative colitis. The endoscopic mucosal inflammation may appear mild in some patients compared to the clinical severity, which can make choosing a treatment challenging. In this study, we evaluated the factors that support the continuation of chemotherapy by assessing the endoscopic and histopathological characteristics of patients who experienced diarrhea after immune checkpoint inhibitor administration.

Methods

This study included eight patients who were diagnosed with collagenous colitis based on pathological assessments. We retrospectively investigated these patients’ backgrounds, laboratory data, and computed tomography images that were extracted from their medical records. We also summarized their endoscopic and pathologic findings.

Results

All eight patients were being treated with anti‐programmed cell death‐1/programmed cell death‐ligand 1 therapeutic agents and had a recent history of oral proton pump inhibitor therapy. The anti‐programmed cell death‐1‐related collagenous colitis in these cases was characterized by endoscopically mild mucosal inflammation, high fecal calprotectin levels, and a lower frequency of intestinal wall thickening on computed tomography. Histological assessments showed CD8⁺ lymphocytes predominantly infiltrating the lamina propria and crypts of the colonic mucosa. Suspending the proton pump inhibitor therapy relieved the patients’ symptoms and allowed the continuation of the anti‐programmed cell death‐1/programmed cell death‐ligand 1 therapy.

Conclusions

Anti‐programmed cell death‐1‐related collagenous colitis is reversible; appropriate diagnosis of adverse events is crucial for the continuation of immune checkpoint inhibitor therapy.

Assessment of the incidence and etiology of nosocomial diarrhea in a medical ward in Iraq

This study aimed to detect the incidence, etiology, risk factors, and severity of nosocomial diarrhea among adult inpatients in a medical ward in Iraq. The study was conducted among patients admitted to the medical ward from June 1, 2019, to January 31, 2020, in AL-Sader medical city. The surveillance for nosocomial diarrhea was performed by monitoring every patient in the ward 3 times/week. 1050 patients were admitted to the medical ward in AL-Sader medical city. Of these, 52 patients (mean age 58±12.91 years, range 32 to 80) developed new-onset diarrhea during hospitalization. There was a significant relationship between the severity of diarrhea and age, residence, antibiotic use, including number and duration of antibiotics, immunosuppressive agents (steroids/chemotherapy), duration of hospital stay, level of consciousness, and enema use. Nosocomial diarrhea is a significant clinical problem that complicates about 5% of all admission in the medical ward. Various microorganisms account for nosocomial diarrhea, including E. histolytica, G. lamblia, and Candida. Several risk factors associated with the severe form of nosocomial diarrhea include old age, antibiotic use, immunosuppressive use, and length of hospital stay.

Immune Checkpoint Inhibitor-Associated Colitis: From Mechanism to Management

Immune checkpoint inhibitors (ICIs), as one of the innovative types of immunotherapies, including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors, have obtained unprecedented benefit in multiple malignancies. However, the immune response activation in the body organs could arise immune-related adverse events (irAEs). Checkpoint inhibitor colitis (CIC) is the most widely reported irAEs. However, some obscure problems, such as the mechanism concerning gut microbiota, the confusing differential diagnosis with inflammatory bowel disease (IBD), the optimal steroid schedule, the reintroduction of ICIs, and the controversial prognosis features, influence the deep understanding and precise diagnosis and management of CIC. Herein, we based on these problems and comprehensively summarized the relevant studies of CIC in patients with NSCLC, further discussing the future research direction of this specific pattern of irAEs.

Immune Checkpoint Inhibitor-Induced Gastrointestinal Toxicity: The Opinion of a Gastroenterologist

Immune checkpoint inhibitors (ICIs) are currently an important component of the standard first-line treatment for many neoplasms. Some guidelines recommend ICIs as adjuvant treatment. With their increased use, the incidence of associated immune-mediated adverse reactions will also increase. A significant proportion of these reactions is represented by immune-mediated diarrhea or colitis, hepatitis, and immune-mediated pancreatic damage. The present review aims to highlight the new trends related to the diagnosis and treatment of these adverse effects depending on their degree, from the perspective of the gastroenterologist. To accomplish this, a literature search was performed, and 30 publications were considered relevant (according to the Population, Intervention, Comparison, Outcomes, and Study [PICOS] criteria). The information about each of the three toxicities in this paper was structured in two categories such as differential diagnosis and treatment. This review aims not only to increase awareness of these side effects in the gastroenterology community but also to promote the development of new treatment guidelines with contributions from gastroenterologists.

Nivolumab dose escalation triggered immune checkpoint inhibitor-induced colitis after 147 weeks of prolonged stable use in a patient with lung cancer: a case report

A 56-year-old man with advanced lung adenocarcinoma presented to the emergency department with a 6-day history of diarrhea. He was treated for lung cancer with nivolumab 3 mg/kg (144 mg/body) every 2 weeks (Q2W), followed by an increase to 240 mg Q2W for 147 weeks, for a total of 69 administrations. His dose was then increased to 480 mg/body every four weeks (Q4W) 12 days before his presentation. Clostridioides difficile toxin, cytomegalovirus antigenemia, and stool bacterial cultures were negative. Colonoscopy revealed diffusely edematous granular mucosa with mucosal redness, exudates, loss of vascular pattern, and aphtha throughout the colon but no ulcers. We diagnosed the patient with immune checkpoint inhibitor-induced colitis. We started prednisolone at a dose of 60 mg/day. His symptoms gradually improved, and he recovered without diarrhea on day ten after hospitalization. After prednisolone tapering, his symptoms did not worsen. Colonoscopy showed significant improvement on day 29, and the diffuse redness disappeared. The patient did not experience subsequent recurrence of diarrhea. He had no progression of lung cancer despite the termination of nivolumab for seven months. Here, we report a case of lung cancer in which nivolumab dose escalation after prolonged stable use triggered immune checkpoint inhibitor-induced colitis.

Metachronous Esophageal Ulcers after Immune-mediated Colitis Due to Immune Checkpoint Inhibitor Therapy: A Case Report and Literature Review

Although cases of gastrointestinal toxicity of pembrolizumab have been reported, cases of acute immune-mediated colitis accompanied with metachronous esophageal disorders (esophagitis and ulcer) are rare. We herein report a case of acute colitis and metachronous esophageal ulcers due to an immune-related adverse event following concomitant pembrolizumab chemotherapy for lung adenocarcinoma. To our knowledge, there have so far been no reports of cases in which both acute immune-mediated colitis and metachronous esophageal ulcers developed. We therefore report the details of this case along with a review of the pertinent literature.

Diagnosis and Management of Immune Checkpoint Inhibitor Colitis

Increased use of immune checkpoint inhibitors (ICIs) has created a rise in immune-related adverse events (irAEs), which may affect any system in the body. Gastrointestinal (GI) irAEs such as immune-mediated colitis are common, occurring in 35% to 50% of patients receiving ICIs. GI irAEs usually develop 6 to 8 weeks after ICI initiation and can involve any part of the GI system. Patients with immune-mediated colitis are categorized into 1 of 5 grades based on the National Cancer Institute's Common Terminology Criteria for Adverse Events, which also guide treatment decisions. An infectious cause for the diarrhea should be excluded in all patients. Patients with grade 1 symptoms are managed conservatively. Patients with grade 2 or higher symptoms should undergo a colonoscopy and are treated with systemic corticosteroids and, depending on their response, biologic therapy. The aim of this article is to review the diagnosis and management of patients with immune-mediated colitis, which should be identified early and addressed promptly to avoid detrimental outcomes.

PD-L1 upregulation is associated with activation of the DNA double-strand break repair pathway in patients with colitic cancer

Ulcerative colitis (UC) is a DNA damage-associated chronic inflammatory disease; the DNA double-strand break (DSB) repair pathway participates in UC-associated dysplasia/colitic cancer carcinogenesis. The DSB/interferon regulatory factor-1 (IRF-1) pathway can induce PD-L1 expression transcriptionally. However, the association of PD-L1/DSB/IRF-1 with sporadic colorectal cancer (SCRC), and UC-associated dysplasia/colitic cancer, remains elusive. Therefore, we investigated the significance of the PD-L1/DSB repair pathway using samples from 17 SCRC and 12 UC patients with rare UC-associated dysplasia/colitic cancer cases by immunohistochemical analysis. We compared PD-L1 expression between patients with SCRC and UC-associated dysplasia/colitic cancer and determined the association between PD-L1 and the CD8+ T-cell/DSB/IRF-1 axis in UC-associated dysplasia/colitic cancer. PD-L1 expression in UC and UC-associated dysplasia/colitic cancer was higher than in normal mucosa or SCRC, and in CD8-positive T lymphocytes in UC-associated dysplasia/colitic cancer than in SCRC. Moreover, PD-L1 upregulation was associated with γH2AX (DSB marker) and IRF-1 upregulation in UC-associated dysplasia/colitic cancer. IRF-1 upregulation was associated with γH2AX upregulation in UC-associated dysplasia/colitic cancer but not in SCRC. Multicolour immunofluorescence staining validated γH2AX/IRF-1/PD-L1 co-expression in colitic cancer tissue sections. Thus, immune cell-induced inflammation might activate the DSB/IRF-1 axis, potentially serving as the primary regulatory mechanism of PD-L1 expression in UC-associated carcinogenesis.

A case of immune checkpoint inhibitor-related colitis with a distinctive endoscopic finding of colonic pseudolipomatosis

A man in his 70s received anticancer chemotherapy with the anti-programmed cell death protein-ligand 1 antibody atezolizumab for non-small cell lung cancer. Ten days later, he developed diarrhea and skin rash, which were suspected to be due to immune-related adverse events, and was treated with prednisolone for 2 weeks. Five weeks after atezolizumab administration, he was admitted to our hospital for Common Terminology Criteria for Adverse Events Grade 3 diarrhea and hematochezia. Sigmoidoscopy revealed a dark red color in the mucosa of the transverse colon and multiple whitish mucosal plaques extending from the transverse colon to the rectum. Biopsy specimens revealed empty vacuoles in the lamina propria with infiltration of numerous inflammatory cells, including CD8⁺ T cells. Based on the findings of sigmoidoscopy and histology, the diagnosis was immune checkpoint inhibitor-related colitis with colonic pseudolipomatosis. The endoscopic findings and symptoms were markedly improved by prednisolone administration. We herein report the first case of immune checkpoint inhibitor-related colitis with characteristic endoscopic findings of colonic pseudolipomatosis. It is important to perform endoscopy and histological evaluation to determine the differential diagnosis and treatment strategy for patients treated with immune checkpoint inhibitors.

Multi-detector computed tomography (MDCT)-based severity score as a prognostic tool in patients with suspected immune checkpoint inhibitor therapy associated colitis

OBJECTIVE

This study aimed to assess MDCT as a diagnostic and prognostic tool in patients with suspected immune checkpoint inhibitor (ICI)-related colitis.

MATERIALS AND METHODS

This retrospective cohort study included patients receiving ICIs at three hospitals between 2015 and 2019 who underwent both abdominopelvic MDCT and endoscopic biopsy to workup suspected ICI-related colitis. Two radiologists independently reviewed MDCT images for signs of colitis based on pre-defined features. Diagnostic performance of MDCT was calculated and categorical variables between treatment subgroups were compared. Logistic regression was used to develop proposed MDCT criteria for diagnosis and MDCT severity score based on a combination of MDCT features of colitis to predict the patient outcomes in ICI-related colitis.

RESULTS

A total of 118 MDCT scans from 108 patients were evaluated for suspected colitis, with 72 confirmed ICI-related colitis cases. Sensitivity, specificity, PPV, and NPV of MDCT for diagnosis of ICI-related colitis was 81% (58/72), 52 % (24/46), 73% (58/80), and 63% (24/38), respectively. Small bowel involvement was visualized in 25% of cases with ICI-related colitis (18/72). In melanoma patients presenting with diarrhea grade ≥ 2 (n = 40), MDCT had the best diagnostic performance for ICI-related colitis (specificity = 80% [8/10], PPV = 92% [23/25]). MDCT severity scores predicted intravenous steroid use (OR 10.3, p = 0.004), length of stay > 7 days (OR 9.0, p < 0.001), and endoscopic mucosal ulceration (OR 4.7, p = 0.02).

CONCLUSION

MDCT is a useful diagnostic and prognostic tool for evaluating patients with immune checkpoint inhibitor-related colitis. An MDCT-based severity score enables assessment of disease severity and predicts outcome.

KEY POINTS

• MDCT is useful for the diagnosis of colitis in patients receiving immune checkpoint inhibitor (ICI) therapy, and an MDCT-based severity score allows for prognostication of patient outcomes. • MDCT yielded moderate sensitivity (81%) for diagnosis of ICI-related colitis but limited specificity (52%). However, in symptomatic melanoma patients (grade 2-4 diarrhea) with a high pretest probability, MDCT proved useful for diagnosis with a high PPV (92%). • For ICI-related colitis, our proposed MDCT severity score has prognostic value in predicting intravenous steroid use, prolonged length of stay during inpatient admission (> 7 days), and endoscopic mucosal ulceration.

A Review of Cancer Immunotherapy Toxicity: Immune Checkpoint Inhibitors

Cancer immunotherapy, which leverages features of the immune system to target neoplastic cells, has revolutionized the treatment of cancer. The use of these therapies has rapidly expanded in the past two decades. Immune checkpoint inhibitors represent one drug class within immunotherapy with its first agent FDA-approved in 2011. Immune checkpoint inhibitors act by disrupting inhibitory signals from neoplastic cells to immune effector cells, allowing activated T-cells to target these neoplastic cells. Unique adverse effects associated with immune checkpoint inhibitors are termed immune-related adverse effects (irAEs) and are usually immunostimulatory in nature. Almost all organ systems may be affected by irAEs including the dermatologic, gastrointestinal, pulmonary, endocrine, and cardiovascular systems. These effects range from mild to life-threatening, and their onset can be delayed several weeks or months. For mild irAEs, symptomatic care is usually sufficient. For higher grade irAEs, discontinuation of therapy and initiation of immunosuppressive therapy may be necessary. The management of patients with irAEs involves multidisciplinary care coordination with respect to the long-term goals the individual patient. Clinicians must be aware of the unique and sometimes fatal toxicologic profiles associated with immunotherapies to ensure prompt diagnosis and appropriate management.

Immune Checkpoint Inhibitor-Induced Acute Pancreatitis and Colitis

Given the promising response of immune checkpoint inhibitors (ICPIs) in treating advanced malignancies, their use in clinical practice is on the rise. ICPIs are associated with a wide spectrum of immune-related adverse events (irAEs). The reported side effects of therapy can be severe enough to require interruption or withdrawal. We are presenting a case of a checkpoint inhibitor-induced acute pancreatitis and colitis, treated with high-dose steroids. This case highlights the need for all physicians to be aware of the different presentations of irAEs from checkpoint inhibitors to provide the correct diagnosis and management.

Butyric Acid Increases the Therapeutic Effect of EHLJ7 on Ulcerative Colitis by Inhibiting JAK2/STAT3/SOCS1 Signaling Pathway

Ulcerative colitis (UC) is a refractory chronic disease characterized by bloody diarrhea and mucosal or submucosal ulcers. There is an urgent need of new drugs for the treatment of ulcerative colitis. EHLJ7 is a quaternary coptisine derivative. Herein, we explored the therapeutic effect of EHLJ7 on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in mice. Results showed that EHLJ7 have good effects on DSS-induced colitis. EHLJ7 significantly improved symptoms induced by DSS including of weight loss, colon contracture, disease activity index (DAI), inflammatory infiltration, and so on. Furthermore, results showed that EHLJ7 could enhance short-chain fatty acids (SCFAs) production especially butyric acid, suggesting that EHLJ7 could improve the metabolic disorder of intestinal flora to a certain extent. Further study indicated that EHLJ7 could cooperate with butyrate to exert its anti-ulcerative colitis effect by inhibiting the activation of janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3)/suppressor of cytokine signaling 1 (SOCS1) pathway. Therefore, EHLJ7 has a potential to be developed as a candidate for the treatment of colitis.

Immune checkpoint inhibitor-related luminal GI adverse events

The early promising results of the use of immune checkpoint inhibitors in the treatment of selected malignancies has ushered a new era in cancer research and the development of treatment options. With the increasing use of this class of medications, a wide array of adverse events is becoming evident, many of which will be encountered by the gastroenterologist. The second most common adverse event associated with immune checkpoint inhibitors involves the GI tract and includes diarrhea and colitis. These are experienced by up to 50% of patients on these agents. The severity of these events varies greatly and may range from mild to fatal. Therefore, it is important that the gastroenterologist is aware of the spectrum of potential GI adverse events. For this review, we conducted an extensive literature search and compiled all relevant information pertaining to the luminal GI tract. The presentation, approach to the patient with luminal GI adverse reactions, risk stratification, management, challenging populations, endoscopic considerations and findings, and histologic findings are discussed in this review.