Commensal viruses maintain intestinal intraepithelial lymphocytes via noncanonical RIG-I signaling.

Much attention has focused on commensal bacteria in health and disease, but the role of commensal viruses is understudied. Although metagenomic analysis shows that the intestine of healthy humans and animals harbors various commensal viruses and the dysbiosis of these viruses can be associated with inflammatory diseases, there is still a lack of causal data and underlying mechanisms to understand the physiological role of commensal viruses in intestinal homeostasis. In the present study, we show that commensal viruses are essential for the homeostasis of intestinal intraepithelial lymphocytes (IELs). Mechanistically, the cytosolic viral RNA-sensing receptor RIG-I in antigen-presenting cells can recognize commensal viruses and maintain IELs via a type I interferon-independent, but MAVS-IRF1-IL-15 axis-dependent, manner. The recovery of IELs by interleukin-15 administration reverses the susceptibility of commensal virus-depleted mice to dextran sulfate sodium-induced colitis. Collectively, our results indicate that commensal viruses maintain the IELs and consequently sustain intestinal homeostasis via noncanonical RIG-I signaling.

Adequate antiviral treatment lowers overall complications of cytomegalovirus colitis among inpatients with inflammatory bowel diseases.

BACKGROUND: Cytomegalovirus (CMV) colitis significantly complicates the course of inflammatory bowel disease (IBD), frequently leading to severe flare-ups and poor outcomes. The role of antiviral therapy in hospitalized IBD patients with CMV colitis is currently under debate. This retrospective analysis seeks to clarify the influence of antiviral treatment on these patients. METHODS: We retrospectively reviewed IBD patients diagnosed with CMV colitis via immunohistochemistry staining from colonic biopsies at a major tertiary center from January 2000 to May 2021. The study focused on patient demographics, clinical features, risk factors, prognostic indicators, and antiviral treatment outcomes. RESULTS: Among 118 inpatients, 42 had CMV colitis. Risk factors included hypoalbuminemia and antibiotic use. IBD patients with CMV colitis receiving < 14 days of antiviral therapy had higher complication (72% vs. 43%, p = 0.028) and surgery rates (56% vs. 26%, p = 0.017) compared to those without CMV. Adequate antiviral therapy (≥ 14 days) significantly reduced complications in the CMV group (29% vs. 72%, p = 0.006), especially in Crohn's disease (20% vs. 100%, p = 0.015). Independent predictors of IBD-related complications were CMV colitis (Odds Ratio [OR] 3.532, 90% Confidence Interval [CI] 1.012-12.331, p = 0.048), biological treatment failure (OR 4.953, 95% CI 1.91-12.842, p = 0.001), and adequate antiviral therapy (OR 0.108, 95% CI 0.023-0.512, p = 0.005). CONCLUSION: CMV colitis and a history of biological treatment failure increase complication risks in IBD patients. Adequate antiviral therapy significantly mitigates these risks, highlighting its importance in managing IBD patients with CMV colitis.

Herpes simplex virus type 2 meningitis as a manifestation of Good's syndrome.

Good's syndrome is a primary immunodeficiency phenocopy characterized for thymoma and immunodeficiency. The most frequent clinical presentation is recurrent or opportunistic infections, hematological alterations, and chronic diarrhea. We treated a 66-year-old man who consulted for 5 days of headache and diplopia with right sixth cranial nerve palsy at examination. Patient reported chronic diarrhea and prolonged febrile syndrome accompanied by weight loss of 23 kg in the last year. Exhaustive evaluation revealed Herpes simplex virus (HSV) type 2 meningitis, eosinophilic colitis, and type A thymoma. Severe antibody deficiency (hypogammaglobulinemia) associated with thymoma confirmed the diagnosis of Good's syndrome.

Cytomegalovirus enteritis with intractable diarrhea in infants from a tertiary care center in China.

Background: Cytomegalovirus (CMV) is rarely thought to be the cause of significant gastrointestinal infection in immunocompetent children. CMV colitis is seldom observed in young infants. This study aims to examine the clinical features of CMV colitis in Chinese children.Methods: Patients with infantile onset CMV colitis diagnosed in intestinal tissue at Children's Hospital of Fudan University from 1st January 2017, to 31st January 2019 were enrolled. Clinical data were retrieved from medical records, and the literature on infant CMV colitis was also reviewed.Results: Ten patients were included with a median age of 2.5 months [interquartile range 2.0, 6.3 months]. All 10 patients had diarrhea, 10 patients had anemia, seven patients reported hematochezia, five patients had hypoalbuminemia, five patients had retinitis, two patients had hearing impairment, and one patient had perianal abscess and anal fistula. The patients had punched-out ulcerations, longitudinal ulcerations or irregular ulcerations on the rectum and/or colon. Typical histologic evaluation showed crypt distortion and inflammatory infiltration. CMV inclusion bodies were noted in four patients. Immunohistochemistry on intestinal tissue was performed to diagnose CMV, with all patients positive. After follow-up, all patients are clinically recovered or in remission; six patients received antiviral therapy, and five patients had healed ulcers on endoscopic examination.Conclusions: CMV colitis might be a rare cause of intractable diarrhea in immunocompetent children. Clinicians should be aware of the possibility of CMV colitis in patients with intractable diarrhea.

Late onset CMV disease presenting as a colonic stricture in a liver transplant recipient.

Cytomegalovirus (CMV) is a common opportunistic infection in solid organ transplant (SOT) recipients in the first 6 months after transplant. Late onset CMV infection or disease outside the classical risk period is uncommon and can present with atypical signs and symptoms. Here, we report a case of late onset CMV presenting as a colonic stricture more than 10 years after liver transplantation in the absence of traditional CMV risk factors. We also briefly review CMV colitis presenting as a mass or stricture in SOT recipients.

Are children with protein-losing enteropathy after the Fontan operation at increased risk of cytomegalovirus enteropathy? A report of two cases.

INTRODUCTION: Aetiology of protein-losing enteropathy in single-ventricle type CHD is multi-factorial. REPORT: We describe two Fontan patients with protein-losing enteropathy who presented with cytomegalovirus-associated colitis. DISCUSSION: Fontan patients display risk factors for cytomegalovirus-induced gastroenteropathy that may affect lymph angiogenesis, disease development, and progression. CONCLUSION: Cytomegalovirus enteropathy may be common among Fontan patients who suffer from protein-losing enteropathy. Polymerase chain reaction is important for detection.

Clinical, imaging, endoscopic findings, and management of patients with CMV colitis: a single-institute experience.

PURPOSE: To evaluate clinical, laboratory, imaging, endoscopic findings, treatment, and outcomes of patients with CMV colitis. METHODS: The electronic medical records of 652 patients who had an impression of colitis of unspecified etiology via endoscopic findings between 2011 and 2019 were retrospectively reviewed. There were 9 patients with biopsy-proven CMV colitis and associated CT imaging performed within 1 month of diagnosis. Demographic data, past medical history, symptoms, laboratory, imaging, endoscopic and biopsy findings, colitis-related adverse events, treatment, and management were recorded. RESULTS: Within the group of 9 patients (2 men; median age, 60 years), all were in an immunosuppressed state (8/9 on immunosuppressive medication regimen and 1/9 with untreated AIDS). Presenting symptoms of CMV colitis included bloody stools (9/9), abdominal pain (7/9), and diarrhea (7/9). The most common imaging findings were pericolonic stranding (9/9) and bowel wall thickening (9/9). Endoscopic evaluation noted inflammation (9/9), ulceration (9/9), and erythema (8/9) as the most prevalent impressions. As determined by both imaging and endoscopy, the sigmoid colon was most commonly affected. Patients were treated with valganciclovir alone (3/9) or ganciclovir followed by valganciclovir (6/9). Outcomes included perforated colon (1/9), persistent colitis (3/9), discharge to hospice (1/9), and resolution (4/9). CONCLUSIONS: CMV colitis is generally associated with an immunosuppressed state. Imaging and endoscopic findings can mimic inflammatory, ischemic, and infectious colitides. However, CMV colitis should be included in the differential diagnosis in immunocompromised adults who present to emergency department with bloody stools, acute abdominal pain or diarrhea, and have bowel wall thickening and pericolonic stranding on imaging.

Obstructive Lymphangitis Precedes Colitis in Murine Norovirus-Infected Stat1-Deficient Mice.

Murine norovirus (MNV) is an RNA virus that can prove lethal in mice with impaired innate immunity. We found that MNV-4 infection of Stat1-/- mice was not lethal, but produced a 100% penetrant, previously undescribed lymphatic phenotype characterized by chronic-active lymphangitis with hepatitis, splenitis, and chronic cecal and colonic inflammation. Lesion pathogenesis progressed from early ileal enteritis and regional dilated lymphatics to lymphangitis, granulomatous changes in the liver and spleen, and, ultimately, typhlocolitis. Lesion development was neither affected by antibiotics nor reproduced by infection with another enteric RNA virus, rotavirus. MNV-4 infection in Stat1-/- mice decreased expression of vascular endothelial growth factor (Vegf) receptor 3, Vegf-c, and Vegf-d and increased interferon (Ifn)-γ, tumor necrosis factor-α, and inducible nitric oxide synthase. However, anti-IFN-γ and anti-tumor necrosis factor-α antibody treatment did not attenuate the histologic lesions. Studies in Ifnαßγr-/- mice suggested that canonical signaling via interferon receptors did not cause MNV-4-induced disease. Infected Stat1-/- mice had increased STAT3 phosphorylation and expressed many STAT3-regulated genes, consistent with our findings of increased myeloid cell subsets and serum granulocyte colony-stimulating factor, which are also associated with increased STAT3 activity. In conclusion, in Stat1-/- mice, MNV-4 induces lymphatic lesions similar to those seen in Crohn disease as well as hepatitis, splenitis, and typhlocolitis. MNV-4-infected Stat1-/- mice may be a useful model to study mechanistic associations between viral infections, lymphatic dysfunction, and intestinal inflammation in a genetically susceptible host.

Accuracy of diagnostic tests and a new algorithm for diagnosing cytomegalovirus colitis in inflammatory bowel diseases: a diagnostic study.

PURPOSE: The optimal method for detecting CMV colitis in patients with inflammatory bowel disease (IBD) has not been established. We wanted to investigate which diagnostic test would be most accurate when defining CMV colitis rather by the further clinical course than by using another diagnostic modality. METHODS: All consecutive patients with moderately or severely active IBD who had been tested for CMV by PCR, histology, or antigenemia assay at the two campuses CBF and CCM of the Charité - Universitätsmedizin Berlin between September 2006 and September 2009 were included in this retrospective study. During that time, in patients with a positive CMV test, immunosuppressive treatment of any kind was immediately reduced and antiviral treatment was started. This allowed identifying patients who responded to antiviral treatment and those who only responded to later escalation of immunosuppressive therapy. RESULTS: One hundred and nine patients were identified, out of whom nine were considered to have clinically relevant CMV colitis. Sensitivity and specificity were 1 and 0.94 for CMV PCR and 0.5 and 1 for pp65 antigen immunofluorescence assay from peripheral blood, 0.67 and 0.98 for immunohistochemistry, and 0.17 and 0.98 for hematoxylin-eosin staining. When using absence of leukocytosis, splenomegaly, and steroid refractory disease as clinical parameters to test for CMV colitis, blood CMV PCR and immunohistochemistry were able to exclude CMV colitis in negative patients with a 75% likelihood of positive patients to have clinically relevant CMV colitis. CONCLUSIONS: Blood-based CMV PCR together with simple clinical parameters can exclude clinically relevant CMV colitis at a high specificity.

CMV Infection in Pediatric IBD.

PURPOSE OF REVIEW: Patients with inflammatory bowel disease (IBD) are predisposed to infections. Cytomegalovirus (CMV) colitis in adult IBD patients, particularly ulcerative colitis (UC), is related to severe or steroid-refractory disease. The aim of this review is to summarize the data on the prevalence and role of CMV colitis in children with IBD. RECENT FINDINGS: Data on CMV colitis in children continue to be very limited due to its rarity. As in adults, children with coexisting UC and CMV tend to have more severe colitis, are resistant to corticosteroids, and are at high risk for colectomies on short- and long-term follow-up. In children, as in adults, the significance of CMV colitis, in terms of whether CMV is a pathogen that aggravates acute severe colitis or simply reflects disease severity, is still unknown.

Pathological assessment of gastrointestinal biopsies from patients with idelalisib-associated diarrhea and colitis.

AIM: Idelalisib (IDELA) treatment is associated with diarrhea/colitis (incidence of ∼15% grade ≥3). We performed a retrospective analysis of gastrointestinal biopsies from 29 patients treated with IDELA across nine clinical trials. METHODS: A central core laboratory performed histopathologic review, immunohistochemistry, and droplet digital PCR viral studies. These results were correlated with tissue immune profiling data and morphologic features per modified Geboes score. RESULTS: Out of 29 eligible patients with abdominal pain or diarrhea, 24 (82.8%) had reported adverse event terms of diarrhea and/or colitis. Infectious pathogens were detected in 9/29 samples. Most biopsies presented with mixed/inflammatory infiltrates and contained increased numbers of FOXP3+ cells versus normal controls. CONCLUSION: This study revealed evidence of T-cell dysregulation and a substantial infectious component in association with IDELA-related diarrhea/colitis.

Cytomegalovirus colitis in hospitalized inflammatory bowel disease patients in Taiwan: a referral center study.

BACKGROUND: Colitis is exacerbated in patients with concurrent cytomegalovirus (CMV) infection and inflammatory bowel disease (IBD). We assessed the prevalence and clinical features of CMV colitis in hospitalized IBD patients. METHODS: A retrospective study reviewed the data from January 1, 1998 through December 31, 2013 compiled at the National Taiwan University Hospital. The CMV colitis patients' demographic data, clinical information, treatment regimens, pathologic findings, and outcome were analyzed. RESULTS: A total of 673 IBD patients were hospitalized during the study period. There were 312 patients diagnosed with Crohn's disease (CD) and 361 with ulcerative colitis (UC). CMV colitis was diagnosed as having positive inclusion bodies in colonic tissue. Six of the 312 CD patients (1.9%) and five of the 361 UC patients (1.4%) were diagnosed with CMV colitis. Compared to CD patients without CMV colitis, patients with CMV colitis were more often older (p < 0.005). Higher steroid usage was noted in the CMV positive group compared to age and gender matched CMV negative IBD patients (81.8% vs. 51.5%). Eight patients received ganciclovir treatment. Three patients who did not receive antiviral treatment had colitis flare-ups after the index admission. CONCLUSIONS: The prevalence of CMV colitis in hospitalized IBD inpatients was 1.6% in Taiwan. Two associated factors for CMV colitis in hospitalized IBD patients were that they were elderly in CD and were on higher doses of steroids. Routine histopathology studies and/or PCR for refractory colitis patients are suggested to diagnose CMV colitis. Once the diagnosis is made, antiviral treatment is recommended to decrease the colitis relapse rate.

Disseminated nocardiosis after unrelated bone marrow transplantation.

Nocardiosis is a rare bacterial infection occurring mainly in patients with deficient cell-mediated immunity. Although disseminated nocardiosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a rare complication, it is associated with high mortality. Moreover, after allo-HSCT, nocardiosis may be mistaken for other bacterial or fungal infections because clinical and radiographic findings of pulmonary, cerebral, and cutaneous nocardiosis lesions are non-specific. Here, we report a case of disseminated nocardiosis (caused by Nocardia abscessus) with skin, pulmonary, liver, lymph node, and multiple brain abscesses in a patient after allo-HSCT. The patient initially responded clinically and radiographically to imipenem/cilastin and trimethoprim-sulfamethoxazole therapy. Clinicians should be aware of the possibility of nocardiosis in allo-HSCT recipients who are treated with multiple immunosuppressive agents to control chronic graft-versus-host disease. Accurate diagnosis and identification of disseminated nocardiosis is important to ensure administration of the correct antibiotic regimen.

Cytomegalovirus colitis in a patient undergoing postoperative adjuvant chemotherapy for lung adenocarcinoma with uracil-tegafur.

When we examine a patient with symptoms of acute enteritis in the course of chemotherapy with oral fluoropyrimidines such as uracil-tegafur (often referred to as UFT), we usually suspect 5-fluorouracil-induced enterocolitis. In case of persistent clinical symptoms despite discontinuation of chemotherapy, cytomegalovirus colitis should be considered in the differential diagnosis of chemotherapy-induced enterocolitis. We herein report the case of a patient who underwent surgery for lung adenocarcinoma followed by postoperative adjuvant chemotherapy with uracil-tegafur and was diagnosed as having cytomegalovirus colitis during the therapy. In the course of chemotherapy, cytomegalovirus colitis occasionally occurs even though the patient does not experience severe myelosuppression; thus, it is necessary that we recognize its potential occurrence.

Cytomegalovirus Colitis in an End-Stage Renal Disease Patient Presenting with Lower Gastrointestinal Bleeding.

The authors report a case of cytomegalovirus colitis which is one of uncommon causes of lower gastrointestinal bleeding in a patient with end-stage renal disease receiving hemodialysis. Our patient presented with recurrent episodes of massive hematochezia within 2 months. He had the underlying end-stage renal disease, ischemic heart disease, cerebrovascular disease, hypertension and gout. Colonoscopy revealed multiple clean base ulcers at rectum and sigmoid colon. An active bleeding lesion was rectal ulcer with non bleeding visible vessel which was successfully treated with hemoclipping. The diagnosis of cytomegalovirus colitis was confirmed by pathology from colonic tissues which showed compatible patterns of cytopathic change. Human immunodeficiency virus serology was negative. He was treated with with ganciclovir intravenously for 1 week after the pathological finding was reported. To our knowledge, cytomegalovirus infection should be considered as causative pathogen of colitis and colonic ulcers in end-stage renal disease patients.

Clinical presentation and risk factors for cytomegalovirus colitis in immunocompetent adult patients.

BACKGROUND: Cytomegalovirus (CMV) colitis is a common manifestation of CMV end-organ disease, which has typically been described in immunocompromised hosts. Recently, it has been noted that this also occurs in immunocompetent patients. To gather relevant data about clinical presentation, prognosis, and risk factors for development of CMV colitis in immunocompetent hosts, we analyzed all cases that occurred during a 19-year period at our institution. METHODS: A case-control study was performed to identify risk factors for CMV colitis in immunocompetent hosts. Electronic medical records of individuals who were admitted and diagnosed with CMV colitis between January 1995 and February 2014 at a tertiary care university hospital were reviewed. Two non-CMV colitis patients who were age- and sex-matched were selected as controls for each case. RESULTS: A total of 51 patients with CMV colitis were included in this study along with 102 control patients. Certain conditions including renal disease on hemodialysis, neurologic disease, rheumatologic disease, intensive care unit admission, and exposure to antibiotics, antacids, steroids, or red blood cell (RBC) transfusions within 1 month of diagnosis of colitis were associated with CMV colitis on univariate analysis. Among these, steroid use and RBC transfusion within 1 month were identified as independent risk factors for developing CMV colitis on multivariate analysis. The 30-day mortality rate was 7.8% without any attributable mortality. CONCLUSIONS: Steroid use and RBC transfusion within 1 month of the diagnosis of colitis were independent risk factors for development of CMV colitis in immunocompetent hosts.

CMV in the gut: a critical review of CMV detection in the immunocompetent host with colitis.

As scientific techniques for the detection of cytomegalovirus (CMV) improve, we are able to detect small amounts of CMV in the mucosal wall. As clinicians, we are unsure how to interpret the results of this novel test. There is controversy in the literature as to the significance of the detection of CMV in the gut. Whilst the importance of CMV and reactivation of the virus is clear in those patients such as allograft recipients with established immune compromise, the role is less clear in patients with less damaged immune systems. We explore whether the detection of CMV in such cases influences outcome and how it should be optimally managed. We discuss the optimal management of such cases, according to current guidelines, with a review of the literature.

Acute cutaneous graft-vs.-host disease compared to drug hypersensitivity reaction with vacuolar interface changes: a blinded study of microscopic and immunohistochemical features.

BACKGROUND: Complications from graft-vs.-host disease (GVHD), a major contributor to morbidity and mortality following hematopoietic cell transplantation, may be mitigated by early diagnosis and intervention. However, differentiation between acute cutaneous GVHD and other common skin eruptions that develop in the post-transplantation period, such as drug hypersensitivity reaction, can be challenging clinically and microscopically. Because recent evidence indicates that CD123, a marker of plasmacytoid dendritic cells, can help to distinguish gastrointestinal GVHD from the clinicopathologic mimic cytomegalovirus colitis, we aimed to determine whether CD123 could aid in the diagnosis of acute cutaneous GVHD. METHODS: We studied 12 skin specimens of patients with grades I-II cutaneous GVHD and 12 from patients who had drug hypersensitivity reaction with vacuolar interface changes on biopsy. RESULTS: No differences were seen between the two groups with regards to density or distribution of CD123 expression. Specimens representing GVHD showed significantly less spongiosis (P < 0.001) and fewer dermal eosinophils (P = 0.03) compared to those representing drug hypersensitivity reaction. CONCLUSIONS: We conclude that CD123 does not appear to be a useful ancillary test in the diagnosis of acute cutaneous GVHD. Careful correlation between clinical findings and features with microscopy remains the cornerstone of accurate diagnosis of acute cutaneous GVHD.