Human cytomegalovirus and Epstein-Barr virus infection in inflammatory bowel disease: Need for mucosal viral load measurement

PCR detection of human herpesviruses in colonic mucosa of individuals with inflammatory bowel disease: Comparison with individuals with immunocompetency and HIV infection

BACKGROUND

Detection of human herpesviruses (HHVs) other than cytomegalovirus (CMV) in colonic mucosa of individuals with inflammatory bowel disease (IBD) remains unknown. This study identified eight HHVs in the colonic mucosa of individuals with IBD and compared the results with immunocompetent and human immunodeficiency virus (HIV)-infected individuals.

METHODS

A total of 89 individuals who had colorectal ulcer on colonoscopy were enrolled: 26 with immunocompetency (n = 26), 41 with IBD, and 22 with HIV infection. We examined the colonic ulcers for the presence of eight HHVs-herpes simplex virus (HSV)-1/2, varicella zoster virus (VZV), CMV, Epstein-Barr virus (EBV), HHV-6, HHV-7, and HHV-8-using mucosal PCR.

RESULTS

The IBD group had positivity rates of 0%, 0%, 0%, 53.7%, 24.4%, 39%, 39%, and 0% for HSV-1, HSV-2, VZV, EBV, CMV, HHV-6, HHV-7, and HHV-8, respectively. The positivity rates of EBV and CMV in colonic mucosa increased significantly in the order of the immunocompetent, IBD, and HIV groups (EBV: 23.1%, 53.7%, 72.7%, P for trend = 0.0005; CMV, 7.7%, 24.4%, 54.5%, P for trend = 0.0003, respectively), but no increase was found in the other HHVs. Median mucosal EBV DNA values in the immunocompetent, IBD, and HIV groups were 0, 76, and 287 copies/μg DNA, respectively (P for trend = 0.002). Corresponding median mucosal CMV DNA values were 0, 0, and 17 copies/μg DNA (P for trend = 0.0001). There was no significant difference in the positivity rates of the eight HHVs between ulcerative colitis and Crohn's disease.

CONCLUSION

The HHVs of EBV, CMV, HHV-6, and HHV-7, but not of HSV-1, HSV-2, VZV, or HHV-8, were identified in the colonic mucosa of IBD individuals. EBV and CMV in colonic mucosa was correlated with host immune status in increasing order of immunocompetent, IBD, and HIV-infected individuals.

Differential cellular localization of Epstein-Barr virus and human cytomegalovirus in the colonic mucosa of patients with active or quiescent inflammatory bowel disease

The role of human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) in the exacerbation of inflammatory bowel disease (IBD) is still uncertain. We prospectively investigated the presence of EBV and HCMV infection in both epithelial and immune cells of colonic mucosa of IBD patients, both refractory and responders to standard therapies, in comparison with patients suffering from irritable bowel syndrome who were considered as controls, by using quantitative real-time polymerase chain reaction, immunohistochemistry and in situ hybridization, in an attempt to assess viral localization, DNA load, life cycle phase and possible correlation with disease activity indexes. We obtained clear evidence of the presence of high DNA loads of both viruses in either enterocytes or immune cells of refractory IBD patients, whereas we observed low levels in the responder group and an absence of detectable copies in all cell populations of controls. Remarkably, the values of EBV and HCMV DNA in inflamed mucosa were invariably higher than in non-inflamed areas in both IBD groups, and the EBV DNA loads in the cell populations of diseased mucosa of refractory IBD patients positively correlated with the severity of mucosal damage and clinical indexes of activity. Moreover, EBV infection resulted the most prevalent either alone or in combination with HCMV, while immunohistochemistry and in situ hybridization did not allow us to distinguish between the different phases of viral life cycle. Finally, as regards treatment, these novel findings could pave the way for the use of new antiviral molecules in the treatment of this condition.

Targeting cytomegalovirus during ulcerative colitis flare-ups

Human cytomegalovirus (CMV) is a common cause of opportunistic infection leading to severe and fatal disease in immune-compromised individuals. In inflammatory bowel disease patients, particularly those with ulcerative colitis (UC), CMV is often reactivated because these patients are frequently treated with immunosuppressive agents. Many reports have described the relationship between CMV reactivation and UC exacerbation, however, a therapeutic strategy for CMV infection in UC patients has not been established. Area covered: This review highlights therapeutic strategies for UC patients with CMV infection. Recent findings have suggested a benefit from antiviral therapy in patients with histologically proven CMV colitis and/or a high colonic CMV load as determined by quantitative PCR. Expert commentary: To decide who requires antiviral therapies and when we start antiviral therapies, prospective studies of large numbers of UC patients with CMV infection are needed. However, we should know that the bottom-line therapy for UC patients with CMV infection is to optimally control mucosal inflammation.

NASPGHAN Clinical Report: Surveillance, Diagnosis, and Prevention of Infectious Diseases in Pediatric Patients With Inflammatory Bowel Disease Receiving Tumor Necrosis Factor-α Inhibitors

Children and adolescents with inflammatory bowel disease (IBD) receiving therapy with tumor necrosis factor α inhibitors (anti-TNFα) pose a unique challenge to health care providers in regard to the associated risk of infection. Published experience in adult populations with distinct autoinflammatory and autoimmune diseases treated with anti-TNFα therapies demonstrates an increased risk of serious infections with intracellular bacteria, mycobacteria, fungi, and some viruses; however, there is a paucity of robust pediatric data. With a rising incidence of pediatric IBD and increasing use of biologic therapies, heightened knowledge and awareness of infections in this population is important for primary care pediatricians, pediatric gastroenterologists, and infectious disease (ID) physicians. This clinical report is the result of a consensus review performed by pediatric ID and gastroenterology physicians detailing relevant published literature regarding infections in pediatric patients with IBD receiving anti-TNFα therapies. The objective of this document is to provide comprehensive information for prevention, surveillance, and diagnosis of infections based on current knowledge, until additional pediatric data are available to inform evidence-based recommendations.

TRIM31 promotes Atg5/Atg7-independent autophagy in intestinal cells

Autophagy is responsible for the bulk degradation of cytosolic constituents and plays an essential role in the intestinal epithelium by controlling beneficial host-bacterial relationships. Atg5 and Atg7 are thought to be critical for autophagy. However, Atg5- or Atg7-deficient cells still form autophagosomes and autolysosomes, and are capable of removing proteins or bacteria. Here, we report that human TRIM31 (tripartite motif), an intestine-specific protein localized in mitochondria, is essential for promoting lipopolysaccharide-induced Atg5/Atg7-independent autophagy. TRIM31 directly interacts with phosphatidylethanolamine in a palmitoylation-dependent manner, leading to induction of autolysosome formation. Depletion of endogenous TRIM31 significantly increases the number of intestinal epithelial cells containing invasive bacteria. Crohn's disease patients display TRIM31 downregulation. Human cytomegalovirus-infected intestinal cells show a decrease in TRIM31 expression as well as a significant increase in bacterial load, reversible by the introduction of wild-type TRIM31. We provide insight into an alternative autophagy pathway that protects against intestinal pathogenic bacterial infection.

Cytomegalovirus Colitis, Cytomegalovirus Hepatitis and Systemic Cytomegalovirus Infection: Common Features and Differences

Cytomegalovirus (CMV) is a ubiquitous human herpes virus, which, after often asymptomatic primary infection, establishes a lifelong latent infection that can periodically be reactivated in both immunocompetent and immunosuppressed carriers. Whereas the diagnostic approach in case of a suspicion of CMV reactivation is well defined, the indication for antiviral therapy can often only be made in the context of an extent of organ involvement, the immune status, and comorbidities of the patient. This article reviews the epidemiology, diagnosis, and therapy of CMV reactivation with a focus on inflammatory bowel diseases and potentially different diagnostic and therapeutic approaches in Asia and the Western world.

Cytomegalovirus and ulcerative colitis: Place of antiviral therapy

The link between cytomegalovirus (CMV) infection and inflammatory bowel diseases remains an important subject of debate. CMV infection is frequent in ulcerative colitis (UC) and has been shown to be potentially harmful. CMV reactivation needs to be diagnosed using methods that include in situ detection of viral markers by immunohistochemistry or by nucleic acid amplification techniques. Determination of the density of infection using quantitative tools (numbers of infected cells or copies of the genome) is particularly important. Although CMV reactivation can be considered as an innocent bystander in active flare-ups of refractory UC, an increasing number of studies suggest a deleterious role of CMV in this situation. The presence of colonic CMV infection is possibly linked to a decreased response to steroids and other immunosuppressive agents. Some treatments, notably steroids and cyclosporine A, have been shown to favor CMV reactivation, which seems not to be the case for therapies using anti-tumor necrosis factor drugs. According to these findings, in flare-ups of refractory UC, it is now recommended to look for the presence of CMV reactivation by using quantitative tools in colonic biopsies and to treat them with ganciclovir in cases of high viral load or severe disease.