Orally Administered Human Immunoglobulin Therapy for Norovirus Enteritis in Solid Organ Transplant Recipients: A Case Series at a Single Academic Transplant Center

Norovirus Management and Outcomes in a Multicenter Pediatric Kidney Transplant Population

BACKGROUND

Norovirus is the most common cause of viral gastroenteritis. Studies in adult kidney recipients have documented significant morbidity associated with norovirus infection, but there are few studies in pediatric recipients.

METHODS

Multicenter retrospective cohort study of pediatric kidney transplant recipients with norovirus, confirmed by stool PCR, between January 1, 2008, and December 31, 2018. Outcomes of interest included duration of diarrhea, incidence of chronic diarrhea, management strategies, and graft function.

RESULTS

Forty pediatric kidney transplant recipients from four centers were identified for inclusion. Median age at transplant was 5.4 years (IQR 2.2-11.2 years), and median time post-transplant was 1.9 years (IQR 0.8-3.8 years). Median diarrheal duration was 16 days (IQR 6.0-41.5 days); 15 patients (43%) had acute diarrhea, 8 (23%) had persistent, and 12 (30%) had chronic diarrhea. Twenty-one (53%) patients developed acute kidney injury. Thirty-five (88%) patients required supplemental fluids, 8 (20%) patients underwent immunosuppression reduction for a median of 22 days, 5 (13%) were treated with nitazoxanide, and 5 (13%) received oral immunoglobulin. Acute rejection was diagnosed in 3 (8%) patients within 6 months of norovirus diagnosis. We observed no sustained decline in eGFR at 12 months after diarrhea resolution (median eGFR difference: 2.8 mL/min/1.73 m2 [IQR: -17.1, 7.4]). Of the patients in the cohort, two lost their graft at 6.8 and 30.0 months after the onset of diarrhea.

CONCLUSION

Norovirus is associated with significant morbidity in pediatric kidney transplant recipients. Various treatment interventions are being employed for norovirus infection. Larger studies, both observational and interventional, are needed to determine the optimal treatment.

Presentation, management, and outcomes of norovirus in adult and pediatric solid organ and hematopoietic stem cell transplant recipients: A multicenter, retrospective study

BACKGROUND

Norovirus (NoV) can cause chronic relapsing and remitting diarrhea in immunocompromised patients.  Few multicenter studies have described the clinical course, outcomes, and complications of chronic NoV in transplant recipients.

METHODS

A multicenter retrospective study of adult and pediatric SOT and HSCT recipients diagnosed with NoV between November 1, 2017, and February 28, 2021. Data were obtained from electronic medical records (EMR) and entered into a central REDCap database. Descriptive statistics were calculated.

RESULTS

A total of 280 NoV+ patients were identified across eight sites. The majority were adults (74.1%) and SOT recipients (91.4%). Initial diagnosis of NoV occurred a median of 36 months post-Tx (IQR [15.0, 90.0]). Most NoV cases had >3 diarrheal episodes daily (66.0%), nausea and vomiting (60.1%). Duration of diarrhea varied greatly (median = 10 days, mean = 85.9 days, range (1, 2100)). 71.3% were hospitalized. Adjustment of immunosuppression, including reduction and discontinuation of mToR inhibitor, CNI, and/or MMF, was the most common management intervention for NoV. Other therapies resulted only in temporary improvement. Four patients died within 30 days and three others died by 180 days postdiagnosis. Clinically significant renal dysfunction was observed in 12.5% by 30 days and 21.4% by 180 days post-NoV diagnosis.

CONCLUSION

In HSCT and SOT patients, NoV frequently resulted in severe symptoms, prolonged diarrhea (30% persistent with diarrhea for >30 days), and clinically significant renal dysfunction (up to 21% of patients). Utilized therapies did not reliably result in the resolution of infection demonstrating the need for more effective treatment.

Human norovirus cultivation systems and their use in antiviral research

Human norovirus (HuNoV) is a major cause of acute gastroenteritis and foodborne diseases, affecting all age groups. Despite its clinical needs, no approved antiviral therapies are available. Since the discovery of HuNoV in 1972, studies on anti-norovirals, mechanism of HuNoV infection, viral inactivation, etc., have been hampered by the lack of a robust laboratory-based cultivation system for HuNoV. A recent breakthrough in the development of HuNoV cultivation systems has opened opportunities for researchers to investigate HuNoV biology in the context of de novo HuNoV infections. A tissue stem cell-derived human intestinal organoid/enteroid (HIO) culture system is one of those that supports HuNoV replication reproducibly and, to our knowledge, is most widely distributed to laboratories worldwide to study HuNoV and develop therapeutic strategies. This review summarizes recently developed HuNoV cultivation systems, including HIO, and their use in antiviral studies.

Metagenomic Surveillance of Viral Gastroenteritis in a Public Health Setting

Norovirus is the primary cause of viral gastroenteritis (GE). To investigate norovirus epidemiology, there is a need for whole-genome sequencing and reference sets consisting of complete genomes. To investigate the potential of shotgun metagenomic sequencing on the Illumina platform for whole-genome sequencing, 71 reverse transcriptase quantitative PCR (RT-qPCR) norovirus positive-feces (threshold cycle [CT], <30) samples from norovirus surveillance within The Netherlands were subjected to metagenomic sequencing. Data were analyzed through an in-house next-generation sequencing (NGS) analysis workflow. Additionally, we assessed the potential of metagenomic sequencing for the surveillance of off-target viruses that are of importance for public health, e.g., sapovirus, rotavirus A, enterovirus, parechovirus, aichivirus, adenovirus, and bocaparvovirus. A total of 60 complete and 10 partial norovirus genomes were generated, representing 7 genogroup I capsid genotypes and 12 genogroup II capsid genotypes. In addition to the norovirus genomes, the metagenomic approach yielded partial or complete genomes of other viruses for 39% of samples from children and 6.7% of samples from adults, including adenovirus 41 (N = 1); aichivirus 1 (N = 1); coxsackievirus A2 (N = 2), A4 (N = 2), A5 (N = 1), and A16 (N = 1); bocaparvovirus 1 (N = 1) and 3 (N = 1); human parechovirus 1 (N = 2) and 3 (N = 1); Rotavirus A (N = 1); and a sapovirus GI.7 (N = 1). The sapovirus GI.7 was initially not detected through RT-qPCR and warranted an update of the primer and probe set. Metagenomic sequencing on the Illumina platform robustly determines complete norovirus genomes and may be used to broaden gastroenteritis surveillance by capturing off-target enteric viruses. IMPORTANCE Viral gastroenteritis results in significant morbidity and mortality in vulnerable individuals and is primarily caused by norovirus. To investigate norovirus epidemiology, there is a need for whole-genome sequencing and reference sets consisting of full genomes. Using surveillance samples sent to the Dutch National Institute for Public Health and the Environment (RIVM), we compared metagenomics against conventional techniques, such as RT-qPCR and Sanger-sequencing, with norovirus as the target pathogen. We determined that metagenomics is a robust method to generate complete norovirus genomes, in parallel to many off-target pathogenic enteric virus genomes, thereby broadening our surveillance efforts. Moreover, we detected a sapovirus that was not detected by our validated gastroenteritis RT-qPCR panel, which exemplifies the strength of metagenomics. Our study shows that metagenomics can be used for public health gastroenteritis surveillance, the generation of reference-sets for molecular epidemiology, and how it compares to current surveillance strategies.

Noroviral diarrhea in solid organ transplant recipients: An analysis of interventions and outcomes

INTRODUCTION

Noroviral infection can lead to chronic diarrhea in solid organ transplant (SOT) recipients with significant morbidity and mortality. Existing literature has described a wide spectrum of illness and has not come to a consensus on the optimal management of this condition.

METHODS

We undertook a retrospective review of all adult SOT recipients between 1/1/2018 and 12/31/2020 who were diagnosed with their first episode of noroviral diarrhea (NVD). Demographic, clinical interventions, and outcomes within 6 months of diagnosis were recorded. Patients' outcomes were classified as either resolved, improved or persistent at 6 months.

RESULTS

Seventy-nine SOT recipients were included. Thirty-eight patients (48%) had chronic diarrhea at baseline (CDB). Thirty-two patients (40%) received nitazoxanide, 28 patients (35%) had their immunosuppression adjusted and seven patients (9%) received intravenous immunoglobulin. Diarrhea improved or resolved in 68 patients (85%). Improvement or resolution of diarrhea was observed in 98% of those who did not have history of chronic diarrhea versus 74% in those who did (p = .002). NVD improved in all 12 patients who had mycophenolate discontinued, although this was not statistically significant (p = .131).

CONCLUSION

CDB was associated with worse outcomes regardless of intervention. A low threshold to test for NVD in SOT recipients with chronic diarrhea is prudent to prevent delayed diagnosis.

Unsuccessful treatment of chronic norovirus infection with enteral immunoglobulin in patients with common variable immunodeficiency, case report

Background

Norovirus gastroenteritis is commonly an acute infection that lasts 2-3 days, but in immunocompromised patients norovirus can cause a chronic gastroenteritis lasting for years. Norovirus replicates in the gastrointestinal tract, but the pathway of viral clearance is not yet known. Promising results of enterally administered immunoglobulin in the treatment of chronic norovirus gastroenteritis in immunocompromised patients have previously been published.

Case presentation

We report two individuals with common variable immunodeficiency and chronic debilitating norovirus gastroenteritis. Both patients were treated with enterally administered immunoglobulin via a duodenal feeding tube as other treatment modalities have been unsuccessful. The patients did not experience any immediate or long-term benefit of enterally administered immunoglobulin.

Conclusion

Despite previous case reports of successful treatment of chronic norovirus infection among immunocompromised patients with enterally administered immunoglobulin, these two patients experienced no benefit of the treatment. This demonstrates the need for further research in treatment of chronic norovirus infection in immunocompromised patients.

Clinical and In Vitro Evidence Favoring Immunoglobulin Treatment of a Chronic Norovirus Infection in a Patient With Common Variable Immunodeficiency

BACKGROUND

Immunocompromised individuals can become chronically infected with norovirus, but effective antiviral therapies are not yet available.

METHODS

Treatments with nitazoxanide, ribavirin, interferon alpha-2a, and nasoduodenally administered immunoglobulins were evaluated sequentially in an immunocompromised patient chronically infected with norovirus. In support, these components were also applied to measure norovirus inhibition in intestinal enteroid cultures in vitro. Viral RNA levels were determined in fecal and plasma samples during each treatment and viral genomes were sequenced.

RESULTS

None of the antivirals resulted in a reduction of viral RNA levels in feces or plasma. However, during ribavirin treatment, there was an increased accumulation of virus genome mutations. In vitro, an effect of interferon alpha-2a on virus replication was observed and a genetically related strain was neutralized effectively in vitro using immunoglobulins and post-norovirus-infection antiserum. In agreement, after administration of immunoglobulins, the patient cleared the infection.

CONCLUSIONS

Intestinal enteroid cultures provide a relevant system to evaluate antivirals and the neutralizing potential of immunoglobulins. We successfully treated a chronically infected patient with immunoglobulins, despite varying results reported by others. This case study provides in-depth, multifaceted exploration of norovirus treatment that can be used as a guidance for further research towards norovirus treatments.

Norovirus disease among older adults

Norovirus, a leading cause of gastroenteritis outbreaks worldwide, results in substantial direct and indirect healthcare costs. Adults older than 65 years of age bear a significant proportion of the disease burden, and the disease course in this population is often more severe and protracted. In this narrative review, we discuss the epidemiology of norovirus infection, mechanisms of pathogenesis, and transmission pertinent to outbreaks along with infection prevention and control efforts. We also describe the clinical manifestations of norovirus disease with a focus on individuals older than 65 years of age, diagnosis and available treatment options, and the challenges and progress within vaccine development.

Serological Humoral Immunity Following Natural Infection of Children with High Burden Gastrointestinal Viruses

Acute gastroenteritis (AGE) is a major cause of morbidity and mortality worldwide, resulting in an estimated 440,571 deaths of children under age 5 annually. Rotavirus, norovirus, and sapovirus are leading causes of childhood AGE. A successful rotavirus vaccine has reduced rotavirus hospitalizations by more than 50%. Using rotavirus as a guide, elucidating the determinants, breath, and duration of serological antibody immunity to AGE viruses, as well as host genetic factors that define susceptibility is essential for informing development of future vaccines and improving current vaccine candidates. Here, we summarize the current knowledge of disease burden and serological antibody immunity following natural infection to inform further vaccine development for these three high-burden viruses.

Norovirus in Cancer Patients: A Review

Norovirus (NoV) is the leading cause of viral-related diarrhea in cancer patients, in whom it can be chronic, contributing to decreased quality of life, interruption of cancer care, malnutrition, and altered mucosal barrier function. Immunosuppressed cancer patients shed NoV for longer periods of time than immunocompetent hosts, favoring quasispecies development and emergence of novel NoV variants. While nucleic acid amplification tests (NAATs) for NoV diagnosis have revolutionized our understanding of NoV burden of disease, not all NAATs provide information on viral load or infecting genotype. There is currently no effective antiviral or vaccine for chronic NoV infections. Screening for inhibitors of NoV replication in intestinal organoid culture models and creation of NoV-specific adoptive T cells are promising new strategies to develop treatments for chronic NoV in immunosuppressed patients. Herein we summarize data on the epidemiology, clinical manifestations, diagnostic challenges, and treatment of NoV infection in patients with cancer.

Healthcare associated diarrhea, not Clostridioides difficile

PURPOSE OF REVIEW

The aim of this article is to review the epidemiology, cause, diagnostic evaluation, and management of healthcare-associated diarrhea (HCAD) with particular attention to current epidemiology and recent developments in diagnostics.

RECENT FINDINGS

Multiplex polymerase chain reaction gastrointestinal panels allow rapid detection of a wide array of potential enteropathogens but the role, yield, and utility of these tests have not been systematically assessed in patients with HCAD. Recent epidemiologic studies reaffirm that HCAD is predominantly a noninfectious condition most often caused by medications or underlying medical conditions, sometimes Clostridioides difficile, and occasionally viruses. Other infections are rare.

SUMMARY

Clinical assessment remains fundamental to the evaluation of HCAD and targeted testing for C. difficile is sufficient in most patients. Multiplex gastrointestinal panels may have a role in immunocompromised patients but more study is needed. Medication-induced diarrhea is common and underappreciated and not limited to antibiotics, laxatives, and enemas.

Norovirus Infections in Kidney Transplant Recipients

BACKGROUND

Norovirus (NoV) infection frequently progresses to chronic disease after kidney transplant (KTx). This study aims to assess potential risk factors helping to determine patients at risk of chronic NoV infection and to analyse the effect of NoV on allograft outcome. Additionally, we assessed the effectiveness of intravenous immunoglobulin (IVIg) therapy for chronic NoV infection.

METHODS

The study enrolled 60 KTx patients requiring hospitalization because of NoV infection. Clinical parameters, severity of NoV infection and potential risk factors were evaluated. Outcome parameters were clinical symptoms, rehospitalizations, persistent shedding of virus and effects on allograft function.

RESULTS

Patients were divided into 2 groups: 29 had acute NoV infection only, 31 progressed to chronic NoV infection. Chronic NoV infection was defined as a recurrence of clinical symptoms plus redetection of NoV in stool. Lymphocyte-depleting induction therapy and diabetes mellitus were independent risk factors for chronic infection. For patients with chronic NoV infection, length of stay in hospital was significantly prolonged (p= 0.024). Allograft function remained impaired in the chronic NoV group 6 and 12 months after initial admission.IVIg was administered to 18 patients with chronic NoV infection. No further clinical symptoms of NoV infection occurred in 13 (72%) of these patients. However, NoV was still detectable in stool specimens from 10 (77%) of these patients.

CONCLUSIONS

Chronic NoV infection is associated with reduced allograft function. Administration of IVIg to patients with chronic NoV infection seems beneficial in achieving freedom from clinical symptoms, despite limited effects on shedding of virus.