Rapid cytomegalovirus pp65 antigenemia assay by direct erythrocyte lysis and immunofluorescence staining

The role of viruses in human acute appendicitis: a systematic literature review

BACKGROUND

There have been debates about the human appendix function, and while previous research suggested it might be a vestigial organ with no functional significance, recent studies have pointed out that it might have an important role in the immune system. Acute appendicitis (AA) is a common cause of emergency abdominal surgery in the world. Some epidemiologic investigations have found an association between appendicitis and viral infections. In this study, we have reviewed systematically articles to discover viral infections that cause appendicitis and find any possible correlations between the two.

METHODS

This systematic review was performed by searching among electronic databases including Web of Science, PubMed, Scopus, and EMBASE on viruses and appendicitis topics.

RESULTS

Conducted search leads to 983 results in all databases after the duplicate removal and screening by title, abstract, and full-text based on inclusion criteria lead to 19 studies. There were several assays to detect the viruses, which are thought to be AA causative agents. RT-PCR and immunoassays were the mainstay methods to detect the probable cause.

CONCLUSION

Investigations suggested that some viruses including measles virus (MV), influenza virus, dengue fever virus (DFV), human immunodeficiency virus (HIV), human herpesviruses, rotavirus, and adenovirus are associated with acute appendicitis. Despite the available reports, the specific mechanisms behind the relationship between acute appendicitis and viral infections are yet to be understood. Therefore, further investigations are necessary to find out the pathogenesis and pathophysiology of viral complications in appendicitis.

Cell therapy for cytomegalovirus infection

INTRODUCTION

Cytomegalovirus (CMV) infection is widely prevalent but mostly harmless in immunocompetent individuals. In the post hematopoietic stem cell transplant (HSCT) setting unrestricted viral replication can cause end-organ damage (CMV disease) and, in a small proportion, mortality. Current management strategies are based on sensitive surveillance programmes, with the more recent introduction of an effective prophylactic antiviral drug, letermovir, but all aim to bridge patients until reconstitution of endogenous immunity is sufficient to constrain viral replication.

AREAS COVERED

Over the past 25 years, the adoptive transfer of CMV-specific T-cells has developed from the first proof of concept transfer of CD 8 + T-cell clones, to the development of 'off the shelf' third party derived Viral-Specific T-cells (VSTs). In this review, we cover the current management of CMV, and discuss the developments in CMV adoptive cellular therapy.

EXPERT OPINION

Due to the adoption of letermovir as a prophylaxis in standard therapy, the incidence of CMV reactivation is likely to decrease, and any widely adopted cellular therapy needs to be economically competitive. Current clinical trials will help to identify the patients most likely to gain the maximum benefit from any form of cell therapy.

Pentostatin, Cyclophosphamide, and Rituximab Followed by Alemtuzumab for Relapsed or Refractory Chronic Lymphocytic Leukemia: A Phase 2 Trial of the ECOG-Acrin Cancer Research Group (E2903)

Patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL) may benefit from salvage chemoimmunotherapy (CIT). To explore further the use of CIT in the pre-novel agent era, ECOG-ACRIN undertook a phase 2 trial (E2903) for R/R CLL utilizing pentostatin, cyclophosphamide, and rituximab (PCR) followed by a consolidation course of alemtuzumab. This trial enrolled 102 patients with a median age of 64 years. Treatment consisted of 6 cycles of PCR followed by alemtuzumab for either 4 or 18 weeks depending on the initial response to PCR. The overall response after PCR (complete remission, CR, nodular partial remission, nPR, and partial remission, PR) was 55%. Major responses (CR or nPR) were achieved in 6%. The median overall survival (OS) and the median progression-free survival were 28 and 12 months, respectively. The most serious nonlethal adverse events were myelosuppression, febrile neutropenia, fatigue, nausea, and hyponatremia. PCR is an effective and well-tolerated nucleoside-based regimen for heavily pretreated CLL patients with R/R disease. The addition of alemtuzumab to CLL patients with a minor response (PR) or stable disease did not result in a significant number of higher responses (CR or nPR) nor an improvement in OS.

Human cytomegalovirus-specific T-cell receptor engineered for high affinity and soluble expression using mammalian cell display

T-cell receptors (TCR) have considerable potential as therapeutics and antibody-like reagents to monitor disease progression and vaccine efficacy. Whereas antibodies recognize only secreted and surface-bound proteins, TCRs recognize otherwise inaccessible disease-associated intracellular proteins when they are presented as processed peptides bound to major histocompatibility complexes (pMHC). TCRs have been primarily explored for cancer therapy applications but could also target infectious diseases such as cytomegalovirus (CMV). However, TCRs are more difficult to express and engineer than antibodies, and advanced methods are needed to enable their widespread use. Here, we engineered the human CMV-specific TCR RA14 for high-affinity and robust soluble expression. To achieve this, we adapted our previously reported mammalian display system to present TCR extracellular domains and used this to screen CDR3 libraries for clones with increased pMHC affinity. After three rounds of selection, characterized clones retained peptide specificity and activation when expressed on the surface of human Jurkat T cells. We obtained high yields of soluble, monomeric protein by fusing the TCR extracellular domains to antibody hinge and Fc constant regions, adding a stabilizing disulfide bond between the constant domains and disrupting predicted glycosylation sites. One variant exhibited 50 nm affinity for its cognate pMHC, as measured by surface plasmon resonance, and specifically stained cells presenting this pMHC. Our work has identified a human TCR with high affinity for the immunodominant CMV peptide and offers a new strategy to rapidly engineer soluble TCRs for biomedical applications.

Development of a vivo rabbit ligated intestinal Loop Model for HCMV infection

BACKGROUND

Human Cytomegalovirus (HCMV) infections can be found throughout the body, especially in epithelial tissue. Animal model was established by inoculation of HCMV (strain AD-169) or coinoculation with Hepatitis E virus (HEV) into the ligated sacculus rotundus and vermiform appendix in living rabbits. The specimens were collected from animals sacrificed 1 and a half hours after infection.

RESULTS

The virus was found to be capable of reproducing in these specimens through RT-PCR and Western-blot. Severe inflammation damage was found in HCMV-infected tissue. The viral protein could be detected in high amounts in the mucosal epithelium and lamina propria by immunohistochemistry and immunofluorescense. Moreover, there are strong positive signals in lymphocytes, macrophages, and lymphoid follicles. Quantitative statistics indicate that lymphocytes among epithlium cells increased significantly in viral infection groups.

CONCLUSIONS

The results showed that HCMV or HEV + HCMV can efficiently infect in rabbits by vivo ligated intestine loop inoculation. The present study successfully developed an infective model in vivo rabbit ligated intestinal Loop for HCMV pathogenesis study. This rabbit model can be helpful for understanding modulation of the gut immune system with HCMV infection.

Usefulness of the cytomegalovirus antigenemia assay in patients with ulcerative colitis

Background/Aims

Patients with ulcerative colitis (UC) are at high risk for cytomegalovirus (CMV) reactivation. The usefulness of the CMV antigenemia assay in active UC patients has rarely been studied. We assessed whether the assay detects CMV colitis and predicts clinical outcomes in patients with UC.

Methods

We retrospectively reviewed the medical records of patients hospitalized for moderate-to-severe UC from 2003 to 2012. Positive CMV antigenemia was defined as ≥1 pp65-positive cell per 2×10⁵ polymorphonuclear neutrophils. CMV colitis was defined as the presence of inclusion bodies and/or positive immunohistochemistry in the colonic mucosa. The primary outcome was steroid refractoriness, defined as the absence of clinical improvement after intravenous high-dose steroid administration.

Results

A total of 43 patients were enrolled. CMV antigenemia was detected in 12 (27.9%) patients. Positive CMV antigenemia was significantly associated with CMV colitis (P =0.001). The sensitivity and specificity of positive CMV antigenemia for diagnosing CMV colitis were 66.7% and 87.1%, respectively. Steroid refractoriness was found in 11 of 12 (91.7%) and 12 of 31 (38.7%) patients with positive and negative CMV antigenemia, respectively (P =0.002). The independent predictors for steroid refractoriness were positive CMV antigenemia (adjusted odds ratio [OR], 7.73; 95% confidence interval [CI], 1.22-49.19; P =0.030) and a shorter duration from the diagnosis of UC (adjusted OR, 0.99; 95% CI, 0.98-0.99; P =0.025).

Conclusions

The CMV antigenemia assay shows low sensitivity but high specificity for detecting CMV colitis and may predict steroid-refractory UC. Early rescue therapy might be considered in UC patients positive for CMV antigenemia.

Evaluation of an abbreviated protocol for cytomegalovirus pp65 antigenemia testing

The cytomegalovirus antigenemia assay remains a useful tool for monitoring reactivation among transplant recipients. In this study, we compared protocols using direct lysis of small-volume, whole blood (WB) samples vs peripheral blood leukocyte (PBL)-enriched fractions. Of 363 evaluable samples, 51 (14.0%) were positive by one or both methods. Sensitivity, specificity, and negative and positive predictive values were similar (76%, 99%, 96%, and 95% vs 71%, 100%, 96%, and 100% for the WB and PBL methods, respectively). Stratification of qualitative results by WBC count revealed comparable detection rates by each method, although the total number of positive results from leukopenic samples was significantly lower than from nonleukopenic samples (P= .04). Correlation between quantitative results was high, yet the degree of clinical agreement was suboptimal. We conclude that the small-volume, WB lysis method yields results statistically comparable to that of a PBL fractionation method but with fewer technical steps and less complexity.

Development and application of a novel multiplex polymerase chain reaction for semi-quantitation of human Cytomegalovirus in clinical specimens

Human Cytomegalovirus (HCMV) is an important cause of morbidity and occasional mortality in immunocompromised patients. The aims of the study were to develop and apply a multiplex PCR for semi-quantitation of HCMV in clinical specimens, compare its efficiency with pp65 antigenemia assay and real-time PCR. A multiplex PCR combining the primers targeting three regions of the HCMV genome, viz. the morphological transforming region II (mtr II), UL-83 and glycoprotein O (gO) genes for the detection of the genome of HCMV was standardized with HCMV AD169 strain. This was evaluated against pp65 antigenemia assay by applying it on 70 peripheral blood specimens obtained from 70 post-renal transplant recipients. The multiplex PCR and a real-time PCR were prospectively applied to 31 clinical specimens from 29 immunocompromised patients. The multiplex PCR was specific for HCMV. The level of antigenemia and the copy number of the viral DNA as estimated by real-time PCR in the samples positive for all the three targets was significantly higher than in those that were positive for only one or two of the targets. The multiplex PCR provides a simple and effective means of quantifying HCMV in clinical specimens with efficiency equivalent to the pp65 antigenemia assay and real-time PCR.

Evaluation of three polymerase chain reaction tests targeting morphological transforming region II, UL-83 gene and glycoprotein O gene for the detection of human cytomegalovirus genome in clinical specimens of immunocompromised patients in Chennai, India

Background

Human Cytomegalovirus (HCMV) continues to be an important cause of morbidity and occasional mortality in immunocompromised patients. Polymerase chain reaction (PCR) is the most sensitive and commonly used method for the assessment of HCMV infection in the immunocompromised patients at risk from severe associated clinical manifestations. However, there is little consistency in the qualitative PCR used for different regions of HCMV genome. Therefore, the performance of three Qualitative PCR tests to detect HCMV genome in clinical specimens from immunocompromised patients was evaluated. With pp65 antigenemia assay as the "gold standard", nested PCR for morphological transforming region II (mtr II) and glycoprotein O (gO) gene and uniplex PCR for UL 83 gene were applied on 92 consecutive clinical specimens obtained from 74 immunocompromised patients with clinically suspected HCMV disease. Virus isolation was attempted on 12 clinical specimens from six pp65 antigenemia positive patients. Based on the pp 65 antigenemia results as "gold standard", the sensitivity, specificity, positive predictive value and negative predictive value for each PCR was calculated.

Results

The PCR targeting mtr II region showed a higher sensitivity (100%) and negative predictive value (100%) than the other two PCRs in detecting HCMV DNA from clinical specimens obtained from different immunocompromised patient population of Chennai region, India.

Conclusion

The results suggests that the optimal method of detection of HCMV DNA could be achieved by PCR using primer sequences targeting mtr II region of genome of HCMV in Chennai region, India.

Failure to genotype Human Cytomegalovirus by PCR-RFLP method due to sequence variation within the primer binding site

Polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) is one of the rapid methods for genotyping Human Cytomegalovirus (HCMV). When genotyping clinical samples by a sensitive nested PCR-based RFLP method for the glycoprotein B (gB) gene of HCMV, it was found that some of the clinical specimens did not give an amplification signal. Analysis of the prototype sequences of the different genotypes showed base pair mismatches over the primer binding site. An alternative assay is suggested for genotyping of HCMV.

Comparative analysis of a double primer PCR assay with plasma, leukocytes and antigenemia for diagnosis of active human cytomegalovirus infection in bone marrow transplant patients

The aim of the study was to determine the prognostic value of a double primer PCR assay to detect human cytomegalovirus (HCMV) infection or disease in bone marrow transplant (BMT) recipients. A total of 209 blood samples including peripheral blood mononuclear cells (PBMN), polymorphonuclear (PMN) leukocytes and plasma from 26 BMT recipients were tested by PCR assay. To discriminate between latent and active HCMV infection, 177 blood samples were also tested by a quantitative antigenemia assay. HCMV serology status of donors and recipients was determined before transplantation by an enzyme immunosorbent assay method. Using the double primer PCR assay, the number of positive samples increased by an average of 11.6%. Symptomatic active HCMV infection was diagnosed in 14 (53.8%) out of 26 BMT patients. There was a good association between double primer PCR assay of PMN leukocytes and antigenemia assays for detection of active HCMV infection in all patients. Detection of HCMV DNA in PMN leukocytes of BMT patients by double primer PCR assay can be an alternative method for antigenemia assay. However, quantitative PCR methods will be necessary for monitoring antiviral treatment.

Treatment of Cytomegalovirus Disease with Valganciclovir in Renal Transplant Recipients: A Single Center Experience

Recent data suggest valganciclovir (VGC) to be as effective as ganciclovir for cytomegalovirus (CMV) prophylaxis. The objective of this study was to analyze the effect of oral valganciclovir in renal transplant patients with symptomatic CMV infection. Twenty-one patients with symptomatic CMV infection received VGC in doses adjusted to renal function until resolution of CMV antigenemia. The patients were followed for a mean of 5.5 months. During therapy, CMV antigenemia dropped in all patients from pretreatment positive levels of 5.2 +/- 3.7 to negative values of 0.25 +/- 0.2 positive cells/10,000 PBMC (P<0.001). After cessation of therapy, none of patients developed relapse of CMV antigenemia/symptoms within the follow-up. VGC therapy was well tolerated in all patients and no major adverse effects occurred. This pilot trial showed VGC to be safe and highly effective in antiviral therapy after renal transplantation. However, subsequent multicenter clinical trials for treatment of CMV disease are necessary.

A simplified cytomegalovirus pp65 antigenemia assay procedure

A simplified cytomegalovirus (CMV) pp65 antigenemia assay using a one-step erythrocyte lysis, fixation and permeabilization process was compared with a standard protocol, the CMV CINAkit (Argene Biosoft) assay. The results were comparable, both quantitatively and qualitatively. The new method saves time. It also provides flexibility because the cell suspension can be stored so that test completion can be deferred if so desired.

Comparison of the CMV brite turbo assay and the digene hybrid capture CMV DNA (Version 2.0) assay for quantitation of cytomegalovirus in renal transplant recipients

We compared the CMV Brite Turbo Kit (BT) and the Digene Hybrid Capture CMV DNA (version 2.0) assay (HC2) in the quantitation of pp65 antigenemia and cytomegalovirus (CMV) DNA levels in immunosuppressed renal transplant recipients. Of 123 blood specimens collected from 24 renal transplant recipients, BT and HC2 assays detected 35 and 39 positive samples, respectively. The overall concordance rate between the two assays was 90%. Discordant results were observed at low levels of viremia, so that 8 samples were HC2 positive but BT negative and another 4 were BT positive but HC2 negative. There was good correlation (R(2) = 0.766; P<0.01) between the levels of CMV DNA and pp65 antigenemia in the 31 concordant positive samples. Correlation between results obtained with the two assays was confirmed by longitudinal studies for a patient who developed clinical CMV disease. HC2 may be more sensitive at low viremia levels and allow earlier detection of impending CMV disease. The BT assay offered the advantage of a rapid (2-h) turnaround time. We conclude that BT and HC2 assays have similar sensitivity and efficacy in the diagnosis and monitoring of CMV infection and disease in renal transplant recipients. While the HC2 assay would be appropriate for centers that handle a large number of samples, the BT test may be more suitable for small sample numbers or when results are needed urgently.

New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients

In the past three decades since the inception of human organ transplantation, cytomegalovirus (CMV) has gained increasing clinical import because it is a common pathogen in the immunocompromised transplant recipient. Patients may suffer from severe manifestations of this infection along with the threat of potential fatality. Additionally, the dynamic evolution of immunosuppressive and antiviral agents has brought forth changes in the natural history of CMV infection and disease. Transplant physicians now face the daunting task of recognizing and managing the changing spectrum of CMV infection and its consequences in the organ recipient. For the microbiology laboratory, the emphasis has been geared toward the development of more sophisticated detection assays, including methods to detect emerging antiviral resistance. The discovery of novel antiviral chemotherapy is an important theme of clinical research. Investigations have also focused on preventative measures for CMV disease in the solid-organ transplant population. In all, while much has been achieved in the overall management of CMV infection, the current understanding of CMV pathogenesis and therapy still leaves much to be learned before success can be claimed.

2-Hour cytomegalovirus pp65 antigenemia assay for rapid quantitation of cytomegalovirus in blood samples

Of 109 blood samples tested for cytomegalovirus (CMV) antigenemia, 18 (16.5%) were positive. CMV Brite detected 13 and CMV Brite Turbo detected 16 of the 18 positives. There was no significant difference in the number of positive cells detected per sample. The seven discrepant samples contained a median of only one positive cell.

Evaluation of a leukocyte stabilization reagent for use in the cytomegalovirus pp65 antigenemia assay

New erythrocyte lysis and leukocyte stabilization reagents (Streck Laboratories, Inc.) were tested in the cytomegalovirus pp65 antigenemia assay, to determine if whole-blood processing time could be delayed to 24 h postdraw. The combination of these reagents gave results comparable to those for patient samples processed immediately after blood draw.

Quantitation of cytomegalovirus: methodologic aspects and clinical applications

Cytomegalovirus (CMV) is an important pathogen in transplant recipients and human immunodeficiency virus (HIV)-infected individuals. Major progress has been made in developing quantitative detection methods for CMV in recent years. Due to their high sensitivity, these assays can detect CMV early, and quantitation may be useful in predicting the patient's risk for disease and in monitoring the effect of antiviral therapy. This review discusses methodological aspects of currently used quantitative assays for CMV (i.e., viral culture techniques, antigen detection assays, DNA detection assays including PCR, branched-DNA assay, and the DNA hybrid capture assay) and addresses the correlation of systemic and site-specific CMV load and CMV disease in different populations of immunosuppressed patients as well as the response to antiviral treatment. To date, direct antigen detection and molecular techniques have largely replaced traditional culture-based techniques for CMV quantitation. In general, a high systemic CMV load is correlated with CMV disease. This correlation is strong in the HIV-infected population and in solid-organ transplant recipients but less clear in allogeneic marrow transplant recipients. Measuring the viral load at specific anatomic sites may be an alternative way to assess disease activity in situations where the systemic viral load correlates poorly with disease activity. A reduction of the systemic CMV load also correlates with a response to antiviral treatment, but more research is needed to evaluate the role of viral load as a surrogate marker for drug resistance. Due to the widespread use of quantitative CMV detection techniques to direct and monitor antiviral treatment, there is a great need for an assessment of the reproducibility of test results and better standardization of the assays.