Follow-Up of Newborns with Hepatitis B Antigenemia

INTRODUCTION

There is a need for data to evaluate hepatitis B antigenemia in newborns of mothers with hepatitis B virus (HBV) infection. This study aims to investigate this.

METHODS

Newborns with positive serum hepatitis B surface antigen (HBsAg) and/or e antigen (HBeAg) were enrolled in the study.

RESULTS

One hundred and one newborns from 98 HBV-infected mothers were included. Median maternal serum HBV DNA level was 23,200 IU/mL at delivery. Among the newborns, 48 were boys and 53 were girls. Mean birth weight was 3190.5 g. Twenty-one newborns had concurrent seropositive HBsAg and HBeAg, nine had seropositive HBsAg and seronegative HBeAg, and 71 had seronegative HBsAg and seropositive HBeAg. Eight newborns had detectable serum HBV DNA. In the follow-up, serum HBsAg and HBeAg in the newborns with undetectable HBV DNA became negative before 6 months of age. Two infants with detectable HBV DNA were diagnosed with immunoprophylaxis failure, one of whom developed active hepatitis at 3 months of age. Liver biopsy in this case showed significant interface hepatitis, fibrous septa formation, and expansion of portal areas with occasional bridging fibrosis.

CONCLUSIONS

Concurrent HBV viremia and antigenemia in newborns of HBV-infected mothers requires attention, while antigenemia without viremia is often transient.

Factors associated with cytomegalovirus antigenemia in patients with rheumatic disease: A retrospective study

INTRODUCTION

This study aimed to examine the factors associated with cytomegalovirus (CMV) antigenemia and the time of onset of CMV antigenemia among patients with rheumatic diseases.

METHODS

A single-center, retrospective, observational study was conducted in our institution from January 2009 to December 2017. This study included patients with rheumatic diseases who had at least one CMV antigen measurement. Multivariate analysis and receiver operating characteristic analysis was performed.

RESULTS

A total of 249 patients underwent CMV antigenemia assay, and 84 (33.7%) patients tested positive. When the association between CMV antigenemia and possible associated factors was investigated, multivariate analysis showed that daily steroid dose increased the odds of having CMV [odds ratio 16.25, 95% confidence interval (CI), 5.360-49.253]. In this study, the cutoff value of daily steroid dose found in this study (0.45 mg/kg/day) was reasonable in clinical practice, and the area under the curve of the steroid dose was 0.838 [95% CI 0.781-0.882], which was the largest of the known indicators. Moreover, the median time from the start of immunosuppressive therapy to the onset of CMV antigenemia was 30 (interquartile range, 21-44) days, and most of the daily steroid users (85.7%) developed CMV antigenemia within 60 days.

CONCLUSIONS

The daily steroid dose is the most important factor associated with CMV antigenemia. Therefore, monitoring and treatment strategies based on the steroid dose, especially in the initial 2 months, are important.

Highly Prevalent SARS-CoV-2 Antigenemia in COVID-19 Patients

Background

Many issues, such as severity assessment and antibody responses, remain to be answered eagerly for evaluation and understanding of COVID-19. Immune lesion is one of key pathogenesis of the disease. It would be helpful to understand the disease if an investigation on antigenemia and association was conducted in the patients with SARS-CoV-2 infection.

Methods

A total of 156 patients admitted to the First People's Hospital of Hefei or Anhui Provincial Hospital on January to February 2020 were involved in this study. SARS-CoV-2 nucleocapsid (NP) antigen, specific IgM/IgG antibodies, and RNA were detected in sequential sera from three COVID-19 patients, and additional 153 COVID-19 patients by means of NP-antigen capture enzyme-linked immunosorbent assay, colloidal gold quick diagnosis, and real-time RT-PCR, respectively. The clinical types of COVID-19 patients were classified into asymptomatic, mild, moderate, severe, and critical, following on the Chinese guideline of COVID-19 diagnosis and treatment. The demographic and clinical data of patients were obtained for comparable analysis.

Results

NP antigen was detected in 5 of 20 sequential sera collected from three COVID-19 patients with typically clinical symptoms, and 60.13% (92/153) expanded samples collected within 17 days after illness onset. No SARS-CoV-2 RNA segment was detected in these sera. The NP positive proportion reached a peak (84.85%, 28/33) on 6 to 8 days after illness onset. Both NP concentration and positive proportion were increased with the increase of clinical severity of COVID-19. Compared to NP negative patients, NP positive patients had older age [years, medians (interquartile ranges (IQR)), 49 (6) vs. 31 (11)], lower positive proportion of NP specific IgM [27.17% (25/92) vs. 59.02% (36/61)], and IgG [21.74% (20/92) vs. 59.02% (36/61)] antibodies, and longer duration [days, medians (IQR), 24 (10) vs. 21 (13)] from illness to recovery.

Conclusions

SARS-CoV-2 NP antigenemia occurred in COVID-19, and presented highly prevalent at early stage of the disease. The antigenemia was related to clinical severity of the disease, and may be responsible for the delay of detectable SARS-Cov-2 IgM.

Investigation of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions and performance of a rapid diagnostic test for identifying asymptomatic malaria infection in northern Ethiopia, 2015

BACKGROUND

Rapid diagnostic tests (RDTs) are widely used for malaria diagnosis of both symptomatic and asymptomatic infections. Although RDTs are a reliable and practical diagnostic tool, the sensitivity of histidine-rich protein 2 (HRP2)-based RDTs can be reduced if pfhrp2 or pfhrp3 (pfhrp2/3) gene deletions exist in the Plasmodium falciparum parasite population. This study evaluated dried blood spot (DBS) samples collected from a national household survey to investigate the presence of pfhrp2/3 deletions and the performance of the RDT used in the cross-sectional survey in a low transmission setting.

METHODS

The 2015 Ethiopia Malaria Indicator Survey tested household members by RDT and collected DBS samples. DBS (n = 2648) from three regions in northern Ethiopia were tested by multiplex bead-based antigen detection assay after completion of the survey. The multiplex assay detected pan-Plasmodium lactate dehydrogenase (LDH), pAldolase, and HRP2 antigens in samples. Samples suspected for pfhrp2/3 gene deletions (pLDH and/or pAldolase positive but low or absent HRP2) were further investigated by molecular assays for gene deletions. Antigen results were also compared to each individual's RDT results. Dose-response logistic regression models were fit to estimate RDT level of detection (LOD) antigen concentrations at which 50, 75, 90, and 95% of the RDTs returned a positive result during this survey.

RESULTS

Out of 2,648 samples assayed, 29 were positive for pLDH or pAldolase antigens but low or absent for HRP2 signal, and 15 of these samples (51.7%) were successfully genotyped for pfhrp2/3. Of these 15 P. falciparum infections, eight showed single deletions in pfhrp3, one showed a single pfhrp2 deletion, and six were pfhrp2/3 double-deletions. Six pfhrp2 deletions were observed in Tigray and one in Amhara. Twenty-five were positive for HRP2 by the survey RDT while the more sensitive bead assay detected 30 HRP2-positive samples. A lower concentration of HRP2 antigen generated a positive test result by RDT compared to pLDH (95% LOD: 16.9 ng/mL vs. 319.2 ng/mL, respectively).

CONCLUSIONS

There is evidence of dual pfhrp2/3 gene deletions in the Tigray and Amhara regions of Ethiopia in 2015. As the prevalence of malaria was very low (< 2%), it is difficult to make strong conclusions on RDT performance, but these results challenge the utility of biomarkers in household surveys in very low transmission settings.

Detection of SARS-CoV-2 nucleocapsid antigen from serum can aid in timing of COVID-19 infection

SARS-CoV-2 RNA can be detected in respiratory samples for weeks after onset of COVID-19 disease. Therefore, one of the diagnostic challenges of PCR positive cases is differentiating between acute COVID-19 disease and convalescent phase. The presence of SARS-CoV-2 nucleocapsid antigen in serum and plasma samples of COVID-19 patients has been demonstrated previously.

Our study aimed to characterize the analytical specificity and sensitivity of an enzyme-linked immunosorbent assay (Salocor SARS-CoV-2 Antigen Quantitative Assay Kit© (Salofa Ltd, Salo, Finland)) for the detection of SARS-CoV-2 nucleocapsid antigen in serum, and to characterize the kinetics of antigenemia. The evaluation material included a negative serum panel of 155 samples, and 126 serum samples from patients with PCR-confirmed COVID-19.

The specificity of the Salocor SARS-CoV-2 serum nucleocapsid antigen test was 98.0 %. In comparison with simultaneous positive PCR from upper respiratory tract (URT) specimens, the test sensitivity was 91.7 %. In a serum panel in which the earliest serum sample was collected two days before the collection of positive URT specimen, and the latest 48 days after (median 1 day post URT sample collection), the serum N antigen test sensitivity was 95.6 % within 14 days post onset of symptoms. The antigenemia resolved approximately two weeks after the onset of disease and diagnostic PCR.

The combination of simultaneous SARS-CoV-2 antigen and antibody testing appeared to provide useful information for timing of COVID-19. Our results suggest that SARS-CoV-2 N-antigenemia may be used as a diagnostic marker in acute COVID-19.

Detection of SARS-CoV-2 N-antigen in blood during acute COVID-19 provides a sensitive new marker and new testing alternatives

OBJECTIVES

Molecular assays on nasopharyngeal swabs remain the cornerstone of COVID-19 diagnostic. The high technicalities of nasopharyngeal sampling and molecular assays, as well as scarce resources of reagents, limit our testing capabilities. Several strategies failed, to date, to fully alleviate this testing process (e.g. saliva sampling or antigen testing on nasopharyngeal samples). We assessed the clinical performances of SARS-CoV-2 nucleocapsid antigen (N-antigen) ELISA detection in serum or plasma using the COVID-19 Quantigene® (AAZ, France) assay.

METHODS

Performances were determined on 63 sera from 63 non-COVID patients and 227 serum samples (165 patients) from the French COVID and CoV-CONTACT cohorts with RT-PCR confirmed SARS-CoV-2 infection, including 142 serum (114 patients) obtained within 14 days after symptoms' onset.

RESULTS

Specificity was 98.4% (95% confidence interval [CI], 95.3 to 100). Sensitivity was 79.3% overall (180/227, 95% CI, 74.0 to 84.6) and 93.0% (132/142, 95% CI, 88.7 to 97.2) within 14 days after symptoms onset. 91 included patients had a sera and nasopharyngeal swabs collected in the same 24 hours. Among those with high nasopharyngeal viral loads, i.e. Ct value below 30 and 33, only 1/50 and 4/67 tested negative for N-antigenemia, respectively. Among those with a negative nasopharyngeal RT-PCR, 8/12 presented positive N-antigenemia; the lower respiratory tract was explored for 6 of these 8 patients, showing positive RT-PCR in 5 cases.

CONCLUSION

This is the first evaluation of a commercially available serum N-antigen detection assay. It presents a robust specificity and sensitivity within the first 14 days after symptoms onset. This approach provides a valuable new option for COVID-19 diagnosis, only requiring a blood draw and easily scalable in all clinical laboratories.

Ultra-sensitive RDT performance and antigen dynamics in a high-transmission Plasmodium falciparum setting in Mali

BACKGROUND

The recent expansion of tools designed to accurately quantify malaria parasite-produced antigens has enabled us to evaluate the performance of rapid diagnostic tests (RDTs) as a function of the antigens they detect-typically histidine rich protein 2 (HRP2) or lactate dehydrogenase (LDH).

METHODS

For this analysis, whole blood specimens from a longitudinal study in Bancoumana, Mali were used to evaluate the performance of the ultra-sensitive HRP2-based Alere™ Malaria Ag P.f RDT (uRDT). The samples were collected as part of a transmission-blocking vaccine trial in a high transmission region for Plasmodium falciparum malaria. Furthermore, antigen dynamics after successful anti-malarial drug treatment were evaluated in these samples using the Q-Plex Human Malaria Array (4-Plex) to quantify antigen concentrations.

RESULTS

The uRDT had a 50% probability of a positive result at 207 pg/mL HRP2 [95% credible interval (CrI) 160-268]. Individuals with symptomatic infection remained positive by uRDT for a median of 33 days [95% confidence interval (CI) 28-47] post anti-malarial drug treatment. Biphasic exponential decay models accurately captured the population level post-treatment dynamics of both HRP2 and Plasmodium LDH (pLDH), with the latter decaying more rapidly. Motivated by these differences in rates of decay, a novel algorithm that used HRP2:pLDH ratios to predict if an individual had active versus recently cleared P. falciparum infection was developed. The algorithm had 77.5% accuracy in correctly classifying antigen-positive individuals as those with and without active infection.

CONCLUSIONS

These results characterize the performance of the ultra-sensitive RDT and demonstrate the potential for emerging antigen-quantifying technologies in the field of malaria diagnostics to be helpful tools in distinguishing between active versus recently cleared malaria infections.

Rotavirus antigenemia as a common event among children hospitalised for severe, acute gastroenteritis in Belém, northern Brazil

Background

Rotavirus antigenemia and RNAemia (the presence of rotavirus RNA in serum) have been commonly identified among paediatric patients with acute gastroenteritis. In this study we examined the association between rotavirus antigenemia and clinical features, and sought to determine the genotypes of rotaviruses detected in paired stool and serum samples.

Methods

Paired stool and serum samples were obtained from children hospitalised for acute gastroenteritis in Belém, Brazil, between June 2012 and June 2015. The 20-point Vesikari scoring system was used to assess the disease severity upon a retrospective medical record review. Stool and serum samples were primarily screened for the presence of rotavirus antigen using a commercial ELISA assay. The rotavirus isolates from stool and serum samples were genotyped by using the classical reverse-transcriptase polymerase chain reaction (RT-PCR) and/or through nucleotide sequencing of VP4 and VP7 genes. Viral load was estimated using real-time RT-PCR.

Results

In total rotavirus antigen was detected in 109 (24.2%) stool samples from 451 children, whereas antigenemia occurred in 38.5% (42/109) of these patients. We demonstrated that patients positive for rotavirus RNA in paired stool and serum samples were more likely to have a higher frequency of vomiting episodes in a 24-h period (p = 0.0035). Our findings also suggested that children not vaccinated against rotavirus are more likely to develop antigenemia, as compared to those given at least one vaccine dose (p = 0.0151). G12P [8] and G2P [4] genotypes were predominant throughout the study period, accounting for 52.3% (57/109) and 27.5% (30/109) of the typed isolates, respectively. Ten stool-serum pairs could be typed for VP4 and VP7 genes. Seven of these pairs showed concordant results with G2P [4] genotype being detected in stool and serum samples, whereas discrepancies between genotypes (G2P [4]/G2P[NT] and G12P [8]/G2P[NT]) were seen in three pairs.

Conclusions

Rotavirus antigenemia and RNAemia occur in a significant number of children hospitalised for acute gastroenteritis in Belém, Brazil, and may contribute to a greater disease severity, particularly translated into a greater number of vomiting episodes. This study documented a high concordance of genotypes detected in a subgroup of paired stool and serum samples.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1535-2) contains supplementary material, which is available to authorized users.

Incidence of Cytomegalovirus Antigenemia in patients with autoimmune rheumatic diseases: a 3-year retrospective study

OBJECTIVE

To determine the incidence of positive CMV antigenemia (CMV-Ag) in patients with autoimmune rheumatic diseases (AIRD) and to describe the outcomes of these patients.

METHODS

From January 2011 to December 2014, a total of 443 patients with AIRD were enrolled in this retrospective analysis. Demographic, clinical and laboratory data, current clinical manifestations, organs affected by CMV infection, therapeutic management and outcomes were evaluated. The CMV-Ag was considered positive when one cell was detected at least.

RESULTS

CMV-Ag was requested in 70 (15.8%) patients with suspicious CMV infection and was positive in 24 (34.3%). The incidence rate of positive CMV-Ag was 4.97% (95% CI 3.1-7.4%). Systemic lupus erythematosus (SLE) (59%), followed by ANCA-related vasculitis (18.2%) and rheumatoid arthritis (9%) were the diseases more associated with positive CMV-Ag. At the time of CMV infection, SLE patients had moderate to severe disease activity, with high frequency of positive anti-dsDNA antibody (69.2%) and complement consumption (61.5%), as well as high doses of corticosteroids and use of immunosuppressants. The main CMV sites involved were lung (45.5%), bone marrow (40.9%) and gut (27.3%). Mortality rate was 45.5%, especially in those with higher doses of daily oral corticosteroids (107 ± 55.4 mg vs. 71.7 ± 46.3 mg; p = 0.07) and lower number of lymphocytes (309 ± 368.2/mm³ vs. 821 ± 692.9/mm³; p = 0.06).

CONCLUSIONS

Our data showed high incidence of CMV-Ag in AIRD patients, particularly those with SLE and greater disease severity. In addition, it was observed high mortality in these patients, highlighting the CMV infection should be included in differential diagnosis.

Comparison of six commercial antigen kits for detection of Dirofilaria immitis infections in canines with necropsy-confirmed heartworm status

Patient-side test kits for detecting antigenemia in dogs associated with sexually mature female heartworms (Dirofilaria immitis) have been available for three decades, and these tests are continually updated and improved. To define the sensitivity (Se) and specificity (Sp) of contemporary antigen detection tests against cardiopulmonary D. immitis burden, we evaluated five patient-side kits-Anigen Rapid One Step^® (Bio note), SNAP^® 4Dx Plus Test Kit (IDEXX), WITNESS^® Heartworm Canine Heartworm Antigen Test Kit (Zoetis), VetScan^® Canine Heartworm Rapid Test (Abaxis), and Solo Step^® CH Canine Heartworm Antigen Test (Heska), and one microplate ELISA (DiroCHEK^®; Zoetis), using archived canine sera divided into five subclasses of female worms (0, 1-5, 6-20, 21-40, and >40). The patient-side tests were performed once, side-by-side according to each manufacturer's protocol by personnel blinded to the D. immitis status of each dog. The overall Se and Sp of the patient-side kits was ≥97.5 and =94.0%, respectively. For samples from dogs with 1-5, 6-20, and 21-40 D. immitis, the Se was between 96 and 100%, with a slight increase in Se in dogs with ≥41 worms. The agreement between tests for all subclasses of D. immitis burden was between 99 and 100%. The Se and Sp for the ELISA compared with the necropsy results of dogs was 99 and 96%, respectively. Agreement between each patient-side test and the ELISA was between 97 and 100%. All commercially available tests can give practitioners excellent patient-side information, allowing them to make informed decisions on the need for additional diagnostic work-up before instituting new or continuing D. immitis prophylaxis.

Betaherpesvirus Complications and Management During Hematopoietic Stem Cell Transplantation

Two of the four betaherpesviruses, Cytomegalovirus (CMV) and human herpesvirus 6B (HHV-6B), play an important role in opportunistic infections in hematopoietic stem cell transplant (HSCT) recipients. These viruses are ubiquitous in humans and can latently infect mononuclear lymphocytes, complicating the diagnosis of the diseases they cause. Although the detection of viral DNA in a patient's peripheral blood by real-time PCR is widely used for monitoring viral infection, it is insufficient for the diagnosis of virus-associated disease. Theoretically, end-organ disease should be confirmed by detecting either viral antigen or significant amounts of viral DNA in a tissue sample obtained from the involved organ; however, this is often difficult to perform in clinical practice. The frequency of CMV-associated diseases has decreased gradually as a result of the introduction of preemptive or prophylactic treatments; however, CMV and HHV-6B infections remain a major problem in HSCT recipients. Measurement of viral DNA load in peripheral blood or plasma using real-time PCR is commonly used for monitoring these infections. Additionally, recent data suggest that an assessment of host immune response, particularly cytotoxic T-cell response, may be a reliable tool for predicting these viral infections. The antiviral drugs ganciclovir and foscarnet are used as first-line treatments; however, it is well known that these drugs have side effects, such as bone marrow suppression and nephrotoxicity. Further research is required to develop less-toxic antiviral drugs.

Efficacy of a nonadjuvanted recombinant FeLV vaccine and two inactivated FeLV vaccines when subject to consistent virulent FeLV challenge conditions

The purpose of this study was to compare the efficacy of three FeLV vaccines, under identical conditions in a laboratory challenge model that closely mimics natural infection. Four groups of cats (n = 20 per group) were administered two doses of vaccine, 21 days apart, starting at 9-10 weeks of age (Purevax^® FeLV, Versifel^® FeLV, Nobivac^® feline 2-FeLV, and a placebo). Cats were challenged 3 weeks later with a virulent, heterologous FeLV isolate. FeLV antigenemia was determined at weekly intervals from 3 to 15 weeks postchallenge. Circulating proviral DNA was determined on terminal PBMC samples. Following challenge, persistent antigenemia developed in 15 (75%) placebo-vaccinated cats, 3 (15%) cats in the Versifel FeLV vaccinated group, and 1 cat (5%) each in the Purevax FeLV and the Nobivac FeLV vaccinated groups. The prevented fractions for three vaccine groups were 93%, 93%, and 80% respectively. The adjusted p-values for all vaccine group comparisons fail to approach statistical significance. There was excellent agreement between proviral FeLV DNA in circulating PBMCs and persistent antigenemia. It is shown that when cats are managed under the same conditions during a virulent challenge, via the normal route of infection, the tested vaccines all show a comparable degree of protection.

Investigation of a Rotavirus Gastroenteritis Outbreak among Immunosuppressed Patients in a Hospital Setting

OBJECTIVE

Rotavirus (RV) is the most common cause of severe dehydrating diarrhoea in healthy infants and young children. The aims of this study were to investigate a RV outbreak in the pediatric hematology and oncology ward and to examine possible associations between immune status and RV infection.

PATIENTS AND METHODS

Twenty-eight children (19 boys and 9 girls) who were hospitalized for treatment of hematological malignancy and solid organ tumor during the RV outbreak were enrolled in this study. Fourteen of the 28 patients developed RV gastroenteritis (GE) during the observation period. RV antigen and RV IgG and IgA were measured by enzyme-linked immunosorbent assays. RV G and P types were determined by reverse transcriptase-polymerase chain reaction.

RESULTS

Mean duration of RVGE in 14 patients was 13.9 days and mean severity score was 7.4. Two RV strains (G3P [8] and G2P [4]) were mainly circulating in the ward, which might result in the formation of a reassortant G2P [8] strain and mixed infection with G2+3P [8] in the immunocompromised patients. RV antigenemia was detected in 22 of the 28 patients (78.6%). RV-specific IgG titers in acute-phase sera of RVGE group were significantly lower than those in non-RVGE group (P=0.001). Mean age of the patients was significantly lower in RVGE group (5.5 ± 4.6 years) than non RVGE group (10.6 ± 4.5 years) (P=0.015).

CONCLUSION

Our data demonstrate that host factors including age, underlying diseases, and immune status may be associated with the susceptibility of RV infection in immunocompromised patients at the time of the nosocomial infection.

Systemic features of rotavirus infection

A growing body of evidence warrants a revision of the received/conventional wisdom of rotavirus infection as synonymous with acute gastroenteritis. Rotavirus vaccines have boosted our interest and knowledge of this virus, but also importantly, they may have changed the landscape of the disease. Extraintestinal spread of rotavirus is well documented, and the clinical spectrum of the disease is widening. Furthermore, the positive impact of current rotavirus vaccines in reducing seizure hospitalization rates should prompt a reassessment of the actual burden of extraintestinal manifestations of rotavirus diseases. This article discusses current knowledge of the systemic extraintestinal manifestations of rotavirus infection and their underlying mechanisms, and aims to pave the way for future clinical, public health and research questions.

Characteristic endoscopic findings and risk factors for cytomegalovirus-associated colitis in patients with active ulcerative colitis

AIM: To identify characteristic endoscopic findings and risk factors for cytomegalovirus (CMV)-associated colitis in patients with active ulcerative colitis (UC).

METHODS: A total of 149 UC patients admitted to the Department of Gastroenterology, Nagoya University Hospital, from January 2004 to December 2013 with exacerbation of UC symptoms were enrolled in this retrospective study. All medical records, including colonoscopy results, were reviewed. CMV infection was determined by the presence of CMV antigen, CMV inclusion bodies in biopsy specimens, or positive specific immunohistochemical staining for CMV. Multivariate analysis was used to identify independent risk factors for CMV colitis.

RESULTS: Multivariate analysis indicated independent associations with the extent of disease (pancolitis) and use of > 400 mg corticosteroids for the previous 4 wk. In contrast, no association was seen with sex, age at UC diagnosis, immunomodulator use, or infliximab use. Punched-out ulceration was also significantly associated with CMV infection in patients with active UC (odds ratio = 12.672, 95%CI: 4.210-38.143).

CONCLUSION: Identification of a total corticosteroid dose > 400 mg for 4 wk, extensive colitis and a specific endoscopic finding of punched-out ulcer might facilitate the more rapid diagnosis and timely initiation of antiviral therapy for CMV-associated colitis in patients with active UC.

Synthetic RNAi triggers and their use in chronic hepatitis B therapies with curative intent

Current therapies for chronic hepatitis B virus infection (CHB) - nucleos(t)ide analogue reverse transcriptase inhibitors and interferons - result in low rates of functional cure defined as sustained off-therapy seroclearance of hepatitis B surface antigen (HBsAg). One likely reason is the inability of these therapies to consistently and substantially reduce the levels of viral antigen production. Accumulated evidence suggests that high serum levels of HBsAg result in exhaustion of the host immune system, rendering it unable to mount the effective antiviral response required for HBsAg clearance. New mechanistic approaches are required to produce high rates of HBsAg seroclearance in order to greatly reduce off-treatment disease progression. Already shown to be a clinically viable means of reducing gene expression in a number of other diseases, therapies based on RNA interference (RNAi) can directly target hepatitis B virus transcripts with high specificity, profoundly reducing the production of viral proteins. The fact that the viral RNA transcripts contain overlapping sequences means that a single RNAi trigger can result in the degradation of all viral transcripts, including all messenger RNAs and pregenomic RNA. Advances in the design of RNAi triggers have increased resistance to degradation and reduced nonspecific innate immune stimulation. Additionally, new methods to effectively deliver the trigger to liver hepatocytes, and specifically to the cytoplasmic compartment, have resulted in increased efficacy and tolerability. An RNAi-based drug currently in clinical trials is ARC-520, a dynamic polyconjugate in which the RNAi trigger is conjugated to cholesterol, which is coinjected with a hepatocyte-targeted, membrane-active peptide. Phase 2a clinical trial results indicate that ARC-520 was well tolerated and resulted in significant, dose-dependent reduction in HBsAg for up to 57days in CHB patients. RNAi-based therapies may play an important role in future therapeutic regimes aimed at improving HBsAg seroclearance and eliminating the need for lifelong therapy. This paper forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."

[Infection by human cytomegalovirus]

Prevalence of human cytomegalovirus infection is very high worldwide. Following primary infection, the virus remains latent, being able to cause recurrences either by reinfection with a new strain or by reactivation of the replication of the latent virus. The most severe disease is seen in congenital infection and in immunosuppressed patients, in whom the virus act as an opportunistic pathogen. Serological techniques are the methods of choice in primary infection and to determine the immune status against CMV in organ donor and receptor. Although well-standardized studies are lacking, the recent commercial availability of methods that measure cellular immune response are promising to predict the risk of CMV disease in immunosuppressed individuals. Molecular assays, that have gradually been substituting viral culture and/or antigen detection, are the most widely used methods for the diagnosis and control of CMV infection.

Frequency of Toxoplasma gondii in HIV Positive Patients from West of Iran by ELISA and PCR

BACKGROUND

Toxoplasma gondii, the obligate intracellular parasite is life threatening in AIDS patients. Diagnosis of toxoplasmosis is based on serological methods especially increasing of IgM and IgG titers, but finding of parasite or its components (antigenemia) may be beneficial method in order to detection of acute toxoplasmosis in immunocompromised patients.

METHODS

Ninety-four serum samples from HIV positive patients were collected from Sanandaj, Kordistan west of Iran. These patients were lived in Sanandaj of whom 26 were prisoners infected with HIV virus in prison. Toxoplasma gondii antibodies were determined by IgG ELISA. T. gondii antigen was identified by capture-ELISA. PCR was performed on samples with T. gondii antigenemia. CD4+ T cells counts had been determined by flowcytometry and were obtained from records of each patient.

RESULTS

Among the examined HIV seropositive individuals, 19.1% (18/94) and 5.3% (5/94) were positive for Toxoplasma-IgG and antigenemia, respectively. Besides, one of the samples was positively detected by PCR method. Mean age of participants was 37.9 ± 9.5 year. Prevalence of IgG antibody and antgenemia was higher in age group of 40-50 years old. The Mean of CD4+ T cells counts of participants (total of HIV+ patients, IgG positive patients and patients with antigenemia) was 699.2 ± 345.2, 655.1 ± 237.9 and 620.2 ± 215.1 respectively.

CONCLUSION

Capture-ELISA and PCR could confirm the T. gondii acute infection in HIV positive patients. For precise diagnosis of acute toxoplasmosis in HIV positive patient, performance of more studies based on more sensitive types of PCR is suggested.

Experimental Dirofilaria immitis infection in dogs: effects of doxycycline and Advantage Multi® administration on immature adult parasites

To better understand the efficacy of doxycycline and 10% imidacloprid+2.5% moxidectin (Advantage Multi(®); Bayer Animal Health, Shawnee Mission, Kansas) on immature adult Dirofilaria immitis parasites and the results of antigen tests, 12 healthy, randomly selected dogs were experimentally infected with D. immitis and monitored for 407 days. Two dogs in each of three subgroups of four dogs were each infected with six (total of 6 dogs) or 12 (total of 6 dogs) D. immitis infective third-stage larvae (L3) obtained from infected mosquitoes. Doxycycline (10mg/kg per os twice daily×30 days) and 10% imidacloprid+2.5% moxidectin (1ml/kg by topical application every 30 days) treatment was initiated at 105 (Group A) and 149 (Group B) days post infection (PI) in two groups. One subgroup of two dogs given 6 L3 and one subgroup of two dogs given 12 L3 remained as untreated controls (GroupC). Serum obtained regularly throughout the study was evaluated by ELISA (PetChek(®) Heartworm-PF Antigen Test, IDEXX Laboratories, Inc.) for D. immitis adult circulating antigens. Six of the eight dogs in the treated groups had detectable antigenemia starting between 148 and 240 days post infection, but antigen was not detected in any treated dog at the end of the study. In the control subgroups, the dogs that received 6 L3 had no detectable antigen while the two dogs that received 12 L3 had detectable antigen beginning on Day 180 that persisted until the end of the study. None of the infected dogs had evidence of circulating microfilariae. At necropsy, no heartworms were recovered from the treated dogs, but all dogs in the untreated group had viable adult heartworms. These results indicate that early immature adult worms (3.5 and 5 months of age) of D. immitis were susceptible to a combined treatment regimen of doxycycline and 10% imidacloprid+2.5% moxidectin.

Evidences and consequences of extra-intestinal spread of rotaviruses in humans and animals

Rotavirus is recognized as one of the main diarrheal pathogens in young children and animals. The prevailing central dogma of rotavirus infection states that the infection is confined in the gastrointestinal tract. However, increasing evidences indicate that rotavirus infection is systemic. Clinical case reports of systemic manifestations to rotavirus infection in children has continued to accumulate over the past years. The use of animal models provided pathological and molecular evidences for extra-intestinal infection of rotaviruses. The mechanism correlated with the extra-intestinal spread of rotavirus infection from the intestine is through cell-free and cell-associated viremia. The extent of the extra-intestinal spread of rotavirus infection has not yet been fully elucidated; whether it can only affect a limited number of organs and tissues or capable of involving the body as a whole. Moreover, the influence of systemic rotavirus infections remains to be determined. In this review, combination of previous and new data are outlined to help in better understanding of the extra-intestinal infections of rotaviruses.

Medical cure for life-threatening severe cytomegalovirus enteritis in a 71-year-old man

The small bowel is the least common site of involvement in the gastrointestinal tract for cytomegalovirus (CMV) infection. CMV enteritis results in a high rate of emergency surgery for bleeding, perforation, or ileus and a high mortality rate. We report on successful medical treatment for a case of life-threatening severe CMV enteritis. A 71-year-old man, not known to be immunocompromised, suffered diarrhea and periumbilical abdominal pain. Diarrhea persisted and hypoalbuminemia developed, which required total parenteral nutrition. Colonoscopy revealed erosions and redness in the terminal ileum. Esophagogastroduodenoscopy revealed diffuse edema in the duodenum. Enteroclysis showed a narrow and shortened small bowel with an extremely short transit time of the small bowel of <1 min. CMV antigenemia was found on the blood sample. The biopsy specimens from both the duodenum and terminal ileum showed cell infiltration with dominance of eosinophils indicating eosinophilic enteritis. Therefore, ganciclovir 500 mg/day and prednisolone 40 mg/day were started. The diarrhea gradually improved, and a semi-vegetarian diet was started; thereafter, the patient fully recovered. Inclusion bodies were not found in routine hematoxylin-eosin stained sections of the duodenal or ileal specimens. However, a re-evaluation by immunohistochemistry using a monoclonal antibody against CMV revealed positive cells for CMV in both specimens.

The role of the cytomegalovirus antigenemia assay in the detection and prevention of cytomegalovirus syndrome and disease in solid organ transplant recipients: A review of the British Columbia experience

BACKGROUND

The pp65 cytomegalovirus (CMV) antigenemia assay has been used as a means of guiding the pre-emptive therapy of CMV disease in solid organ transplant (SOT) recipients. Recently, concerns have been raised regarding the utility of the test to accurately and precisely detect viral activity early enough to reduce the morbidity and mortality associated with CMV OBJECTIVE: To determine the performance characteristics of the method of antigenemia testing of SOT recipients used at Vancouver General Hospital, Vancouver, British Columbia.

METHODS

All SOT recipients between January 1, 1999, and June 30, 2000, were retrospectively reviewed for six months following transplantation. Physical examination results, laboratory parameters, antigenemia results and treatment information were reviewed.

RESULTS

A total of 134 kidney, liver, lung and kidney-pancreas transplant recipients were included in the analysis. The overall performance characteristics of the antigenemia assay in predicting CMV disease included a sensitivity of 64%, a specificity of 81%, a positive predictive value of 76% and a negative predictive value of 71%. A mean of 18 days passed between the onset of signs and symptoms of CMV disease/syndrome and the first recorded positive antigenemia result, and only 26% of patients had a positive test result before the onset of symptoms. It was found that an antigenemia test breakpoint of at least one positive cell for defining a positive test provided the most sensitive and specific prediction, with increased odds of developing CMV disease.

CONCLUSIONS

Based on performance characteristics, the Vancouver General Hospital's current method of antigenemia testing to guide pre-emptive ganciclovir therapy in SOT patients is not optimal for the early detection of disease. Further study is needed on new molecular testing methods to determine if our ability to predict CMV disease can be improved.

Quantification of CD8(+)CD38(+) T lymphocytes by flow cytometry does not represent a good biomarker to monitor the reactivation of cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Infection/reactivation of cytomegalovirus is a major cause of morbidity and mortality in immunocompromised transplant patients. It has already been observed in kidney and liver transplantation patients that cytomegalovirus disease is accompanied by significant increases in circulating CD8(+)CD38(+) T lymphocytes. There are no reports that study CD8(+)CD38(+) T lymphocytes to monitor/diagnose cytomegalovirus disease in hematopoietic stem cell transplantation patients.

OBJECTIVE

The aim of this study was to evaluate some cellular activation markers on circulating mononuclear cells (CD38 and HLA-DR) in patients submitted to hematopoietic stem cell transplantation and to establish any correlation with cytomegalovirus disease as diagnosed by antigenemia.

METHODS

Blood samples of 15 transplant patients were analyzed by flow cytometry using anti-CD3, anti-CD4, anti-CD8, anti-CD38, CD16, CD56 and anti-HLA-DR monoclonal antibodies and the results were evaluated in respect to cytomegalovirus antigenemia measured by indirect immunofluorescence. Minitab for Windows was used for statistical analysis and a p-value < 0.05 was considered significant.

RESULTS

Patients with positive antigenemia did not show any significant increase in the percentages of cells expressing the CD38 or HLADR activation markers when compared to patients with negative antigenemia. On the contrary, all patients showed high percentages of these cells independent of the presence of cytomegalovirus disease.

CONCLUSIONS

This study suggests that the investigation of these lymphocyte sub-populations in patients submitted to hematopoietic stem cell transplantation does not seem to contribute to the early identification of cytomegalovirus disease.

Comparison of quantitative cytomegalovirus real-time PCR in whole blood and pp65 antigenemia assay: clinical utility of CMV real-time PCR in hematopoietic stem cell transplant recipients

Successful preemptive therapy for cytomegalovirus (CMV) infection in transplant patients depends on the availability of sensitive, specific, and timely diagnostic tests for CMV infection. Although the pp65 antigenemia assay has been widely used for this purpose, real-time quantification of CMV DNA has recently been recognized as an alternative diagnostic approach. However, the guidelines for antiviral therapy based on real-time quantitative polymerase chain reaction (RQ-PCR) have yet to be established. From November 2004 to March 2005, a total of 555 whole blood samples from 131 hematopoietic stem cell transplant (HSCT) recipients were prospectively collected. RQ-PCR was conducted using an Artus CMV LC PCR kit (QIAGEN). Both qualitative and quantitative correlations were drawn between the two methods. Exposure to the antiviral agent influenced the results of the two assays. Additionally, the discrepancy was observed at low levels of antigenemia and CMV DNA load. Via ROC curve analysis, the tentative cutoff value for preemptive therapy was determined to be approximately 2x10(4) copies/mL (sensitivity, 80.0%; specificity, 50.0%) in the high risk patients, and approximately 3x10(4) copies/mL (sensitivity, 90.0%; specificity, 70.0%) in the patients at low risk for CMV disease. Further study to validate the optimal cutoff value for the initiation of preemptive therapy is currently underway.