The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

The IPTA Nashville consensus conference on post-transplant lymphoproliferative disorders after solid organ transplantation in children: I-Methodology for the development of consensus practice guidelines

The International Pediatric Transplant Association (IPTA) Consensus Conference on Practice Guidelines for the Diagnosis, Prevention, and Management of Post-Transplant Lymphoproliferative Disorders after Solid Organ Transplantation in Children took place on March 12-13, 2019, and the work of conference members continued until the end of December 2021. The goal was to produce evidence-based consensus guidelines on the definitions, diagnosis, prevention, and management of PTLD and related disorders based on the critical review of the literature and consensus of experts. This report describes the goals, organization, and methodology of the consensus conference and follow-up activities. The results of each working group (Definitions, Prevention, Management, and Epstein-Barr viral [EBV] load/Biomarker Monitoring) are presented in separate manuscripts within this volume of Pediatric Transplantation.

The IPTA Nashville consensus conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: II-consensus guidelines for prevention

The International Pediatric Transplant Association (IPTA) convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorder after solid organ transplantation in children. In this report from the Prevention Working Group, we reviewed the existing literature regarding immunoprophylaxis and chemoprophylaxis, and pre-emptive strategies. While the group made a strong recommendation for pre-emptive reduction of immunosuppression at the time of EBV DNAemia (low to moderate evidence), no recommendations for use could be made for any prophylactic strategy or alternate pre-emptive strategy, largely due to insufficient or conflicting evidence. Current gaps and future research priorities are highlighted.

Cytomegalovirus transmission in mismatched solid organ transplant recipients: Are factors other than anti-viral prophylaxis at play?

Although antiviral prophylaxis has reduced cytomegalovirus (CMV) DNAemia and disease in seronegative solid organ transplant (SOT) recipients (R-) receiving seropositive donor organs (D+), its impact on CMV transmission is uncertain. Transmission, defined as CMV antigenemia/CMV DNAemia and/or seroconversion by year 2, and associated demographic risk factors were studied retrospectively in 428 D+/R- and 429 D-/R- patients receiving a SOT at our center. The cumulative transmission incidence was higher for lung (90.5%) and liver recipients (85.1%) than heart (72.7%), kidney (63.9%), and pancreas (56.2%) recipients (p < .001) and was significantly lower in living (50.1%) versus deceased donor (77.4%, p < .001) kidney recipients despite identical antiviral prophylaxis. In multivariate analysis, only allograft type predicted transmission risk (HR [CI] lung 1.609 [1.159, 2.234] and liver 1.644 [1.209, 2.234] vs kidney). For 53 D+ donating to >1 R- with adequate follow-up, 43 transmitted to all, three transmitted to none, and seven transmitted inconsistently with lungs and livers always transmitting but donor-matched heart, kidney or kidney-pancreas allografts sometimes not. Kidney pairs transmitted concordantly. CMV transmission risk is allograft-specific and unchanged despite antiviral prophylaxis. Tracking transmission and defining donor factors associated with transmission escape may provide novel opportunities for more targeted CMV prevention and improve outcome analysis in antiviral and vaccine trials.

Epidemiological and Clinical Characteristics of Alveolar Echinococcosis: An Emerging Infectious Disease in Alberta, Canada

Human alveolar echinococcosis (AE) is a zoonotic cestode infection which is usually fatal in the absence of treatment. Treatment involves major surgery or indefinite antiparasitic therapy. The incidence is rising in Europe and Asia, with an increased risk observed in immunocompromised individuals. Previously, AE acquisition in North America was extremely rare, except for one remote Alaskan Island. Recent studies have demonstrated a new European-like strain of Echinococcus multilocularis (Em) in wildlife and in human AE in western Canada. We report the experience of all AE patients diagnosed in Alberta. Each was diagnosed by histopathology, serology, and PCR-confirmed by a reference laboratory. Seventeen cases of human AE, aged 19-78 years, nine females, were diagnosed between 2013 and 2020: all definitely or probably acquired in Alberta. Six lived in urban areas, and 14 had kept dogs. In eight, the lesions were found incidentally on abdominal imaging performed for other indications. Six were immunocompromised to varying degrees. Six were first diagnosed at surgery. All have been recommended benzimidazole therapy. One died of surgical complications. Clinicians should be aware of this diagnostic possibility in patients presenting with focal nonmalignant hepatic mass lesions. Greater urbanization of coyotes, the predominant definitive host of Em in Alberta, and growing numbers of immune suppressed individuals in the human population may lead to increasing recognition of AE in North America.

Transfusion-transmitted and community-acquired cytomegalovirus infection in seronegative solid organ transplant recipients receiving seronegative donor organs

Solid organ transplant (SOT) recipients who are cytomegalovirus (CMV) seronegative (R-) and receive seronegative donor (D-) organs have a small but currently unquantified risk of both transfusion-transmitted CMV (TT-CMV) and community-acquired CMV (CA-CMV). We retrospectively studied the incidence and clinical symptoms of TT-CMV (infection <1 year posttransplant) and CA-CMV (infection >1 year posttransplant) in a cohort of D-/R- adult and pediatric SOT recipients receiving leukoreduced blood products not screened for CMV seronegativity transplanted at our center between 2000 and 2011. CMV infection was defined as IgG seroconversion or detectable CMV antigenemia/DNAemia. Among 536 consecutive D-/R- recipients, 398 (81.8%) had adequate follow-up, and 231 (58%) received cellular blood products (total: 1626 red blood cell units, 470 platelet units) 30 days pretransplant to 90 days posttransplant. We observed no confirmed TT-CMV cases, but 14 CA-CMV cases (64% symptomatic) were seen. The estimated incidence rate of CA-CMV was higher in children (3.0/100 patient years) than adults (0.46/100 patient years, incident rate ratio of 6.52). The absence of TT-CMV over 11 years suggests neither seronegative blood products nor CMV DNA blood donor screening would provide significant incremental safety when blood is already leukoreduced. D-/R- SOT recipients, particularly children, have a significantly higher and ongoing risk of CA-CMV.

Using blood donors and solid organ transplant donors and recipients to estimate the seroprevalence of cytomegalovirus and Epstein-Barr virus in Canada: A cross-sectional study

BACKGROUND

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections are common, causing significant morbidity in pregnancy (congenital CMV) and transplant recipients (CMV, EBV). Canadian prevalence data are needed to model disease burden and develop strategies for future vaccines. We estimated prevalence using screening data from blood donors and solid organ transplant (SOT) donors and recipients.

METHODS

We retrospectively analyzed CMV and EBV serology from Alberta SOT donors (n = 3,016) and recipients (n = 4,614) (1984-2013) and Canadian Blood Services blood donors (n = 1,253,350) (2005-2014), studying associations with age, sex, organ, year, and geographic region.

RESULTS

CMV seroprevalence rises gradually with age. By age 70, CMV seropositivity ranged from 67% (blood donors) to 73% (SOT recipients). Significant proportions of women of child-bearing age were CMV-seronegative (organ donors, 44%; SOT recipients, 43%; blood donors, 61%). Blood donor CMV seroprevalence decreased from 48% in Western Canada to 30% in Eastern Canada. Women were more likely to be CMV-seropositive (ORs = 1.58, 1.45, and 1.11 for organ donors, SOT recipients, and blood donors, respectively) and EBV-seropositive (ORs = 1.87 and 1.46 for organ donors and SOT recipients, respectively). EBV prevalence rises rapidly, and by age 17-29 years, 81% of SOT recipients and 90% of organ donors were seropositive.

CONCLUSIONS

Canada has relatively low and perhaps decreasing age-specific EBV and CMV prevalence, making Canadians vulnerable to primary infection-associated morbidity and suggesting benefit from future vaccines. Collection and analysis of routine serology screening data are useful for observing trends.

1754. Pre-Transplant Vaccination Rates in Solid-Organ Transplant Recipients

Background

Recipients of solid-organ transplants (SOT) are at increased risk of vaccine-preventable illnesses. Because of the immunosuppression administered following SOT, live vaccines are generally contraindicated post-SOT, and response to inactivated vaccines may be suboptimal. National and international guidelines recommend optimizing immunizations prior to SOT. We analyzed rates of vaccination for SOT candidates in a cohort of adult kidney and liver transplant recipients.

Methods

A retrospective chart review of adult kidney, kidney/pancreas (KP) and liver transplant recipients was conducted between 2014 and 2016. We calculated the rates of vaccinations of the following vaccines: pneumococcus, meningococcus, Hepatitis A and B, Haemophilus influenzae type B, measles, mumps, rubella, polio, tetanus, diphtheria and pertussis.

Results

300 patients were included (147 kidney, 14 KP, 139 liver). Liver recipients were older (mean age 53 vs. 50; P = 0.028) and less likely to have had a previous transplant (5.8% vs. 21.1%; P < 0.001) or a living donor (15.8% vs. 32.3%, P = 0.01). Liver recipients were more likely to have been vaccinated against hepatitis A (106 [53.9%] vs. 28 [17.4%]; P < 0.001). Kidney and KP recipients were more likely to have received at least 1 dose of hepatitis B vaccine (138 [85.7%] vs. 91 [65.5%]; P < 0.001) or at least 1 dose of any of the pneumococcal vaccines (PSV23 94 [67.6%] vs. 92 [57.1%]; P = 0.062; PCV13 130 [80.7%] vs. 93 [66.9%]; P = 0.006; pneumococcal vaccine not clarified 47 [29.2%] vs. 14 [10.1%]; P < 0.001). No difference was observed with regards to other vaccines (Table 1). Being a kidney transplant recipient increased the odds of getting at least 1 dose of hepatitis B, tetanus/diphtheria/acellular pertussis (Tdap), measles, and pneumococcal vaccine (OR = 1.75, 95% CI [1.063–2.864]; P = 0.028)

Conclusion

In our cohort, kidney transplant recipients were more likely to have received pre-transplant vaccination. Despite the availability of local and international guidelines, vaccination in SOT candidates remains suboptimal and further study of barriers to implementation of these guidelines is warranted to inform future quality improvement initiatives.

Disclosures

All authors: No reported disclosures.

High incidence of clinically significant cytomegalovirus infection in CMV D+/R+ lung transplant recipients receiving 3 months of antiviral prophylaxis

BACKGROUND

Universal antiviral prophylaxis is the preferred preventive strategy for lung transplant recipients (LTRs) at risk of CMV infection. We compared the risk of CMV infection between CMV D+/R + and D-/R + LTRs after 3 months of prophylaxis.

METHODS

This was a retrospective review of CMV R + LTRs transplanted between 2005 and 2013. Patients dying before completing 3 months, or receiving >180 days of prophylaxis were excluded. The primary outcome was proportion of LTRs who developed CMV infection and clinically significant CMV infection defined as CMV infection leading to preemptive therapy or CMV disease.

RESULTS

We analyzed 90 D+/R + and 72 D-/R + with a median follow up of 730 days. CMV infection and disease was more common in D+/R + compared to D-/R+ (CMV infection 66% vs 40%; P = 0.001; CMV disease 13% vs 4% P = 0.045). Fifty-nine patients developed at least one episode of clinically significant CMV infection (41/90 [46%] D+/R + and 18/72 [25%] D-/R + P=0.007) with recurrence occurring in 29 LTRs (49% of patients with previous CMV infection), of which 22 (76%) were CMV D+/R+. Thirty percent had side effects related to CMV therapy.

CONCLUSION

Three months prophylaxis in D+/R + LTRs was associated with high rates of clinically significant CMV infection and recurrences.

Impact of donor and recipient cytomegalovirus serology on long-term survival of lung transplant recipients

BACKGROUND

Pre-transplant cytomegalovirus (CMV) serostatus has been associated with lung transplant patient survival. We retrospectively analyzed the relationship between pre-transplant donor/recipient CMV serostatus and long-term mortality in a cohort of lung transplant recipients at our center.

METHOD

Adult (Age >17 years) lung recipients transplanted between July 1985-December 2015 were analyzed. Variables included age, sex, pre-transplant donor (D)/recipient (R) serostatus [D-/R-, D-/R+, D+/R+, D+/R-], CMV infection within 2 years of transplant and transplant eras divided by changes in CMV prevention strategies: Era 1 (pre-ganciclovir, July 1985-April 1998), Era 2 (oral ganciclovir, May 1998-December 2004), Era 3 (valganciclovir, January 2005-December 2015). Survival analysis and Cox regression were performed at 10 years.

RESULTS

A total of 652 lung recipients were analyzed. Twenty percent were CMV mismatched pre-transplant and 45% had CMV infection within 2 years post-transplant. Survival at 10 years appeared worse in D+ transplants (P = 0.027). D-/R- lungs did not have significantly different survival across eras (P = 0.76), but survival of D-/R+, D+/R+, D+/R- lungs improved (P < 0.001). Cox regression revealed that transplantation in the valganciclovir era reduced risk of death in lung transplants by an estimated 52% (P < 0.001) compared to transplantation in the pre-ganciclovir era after controlling for age at transplant, D/R CMV serostatus and CMV infection. Age at transplant and CMV infection were also significant predictors of mortality in lung transplants (P < 0.001 and 0.033 respectively).

CONCLUSION

Our review of the impact of CMV managed differently across eras suggests in lung transplantation there is no independent influence of D/R CMV serostatus on 10-year survival.

Radiation Exposure from Diagnostic Imaging in a Cohort of Pediatric Transplant Recipients

Recipients of solid organ transplants (SOT) have extensive diagnostic imaging (DI). The purpose of this study was to quantify this exposure. Children from northern Alberta with SOTs at Stollery Children’s Hospital, Edmonton, Alberta January 1, 2006, to July 31, 2012, were included. Effective doses of radiation were estimated using published norms for DI performed post-transplant up to October 16, 2014. The 54 eligible children had 6215 DI studies (5628 plain films, 293 computerized tomography (CT) scans, 149 positron emission topography (PET) -CT scans, 47 nuclear medicine scans and 98 cardiac catheterizations). Children less than 5 years of age underwent more DI studies than did older children (median (IQR) 140 (66–210) vs 49 (19–105), p = 0.010). Children with post-transplant lymphoproliferative disorder (N = 8) had more CT scans (median (IQR) 13 (5.5–36) vs 1 (0–5), p<0.001) and PET-CT scans (median (IQR) 3.5 (1.5–8) vs 0 (0–0), p<0.001) than did other children. The estimated cumulative effective dose attributed to DI studies post-transplant was median (range) 78 (4.1–400) millisievert (mSv), and 19 of 54 children (35%; 95% confidence interval 24–49%) had a dose >100 mSv. In conclusion, a significant proportion of pediatric transplant recipients have sufficient radiation exposure post-transplant for DI to be at potential risk for radiation-induced malignancies.

Sentinel surveillance of HIV and hepatitis C virus in two urban emergency departments

Objectives:

This study was designed to determine the prevalence of HIV and hepatitis C virus (HCV) in a specific population, and to distinguish between known and previously unrecognized infections in the emergency department (ED) setting.

Methods:

Consecutive patients aged 15 to 54 years who had presented to the EDs of 2 urban hospitals during a 6-week period were enrolled in a prospective cross-sectional study if a complete blood count had been obtained as part of their care. The study patients were initially cross-referenced against local databases of known HIV and HCV seropositive patients. After removal of all personal identifiers, the study patients’ leftover blood was serotested for HIV and HCV, and seroprevalences were calculated. Univariate and multivariate analyses were performed to identify factors associated with HIV and HCV infection.

Results:

Of 3057 individuals whose files were analyzed, 1457 (48%) were male and 7% (213) were Aboriginal. Overall, 302 patients (10%; 95% confidence interval [CI], 9%–11%) were seropositive for HCV and, of these, only 132 (44%) were previously known to be. HCV seropositivity was associated with Aboriginal status, age, male gender, hospital site and HIV infection (allp&lt; 0.001). In contrast, 39 patients (1%; 95% CI, 1%–2%) were HIV seropositive. Of these, 32 (82%) were previously known to be HIV positive, and 27 (69%) were HCV seropositive. HIV seropositivity was only associated with HCV infection (p&lt; 0.001).

Conclusions:

The rate of previously undetected infections was relatively low for HIV but high for HCV. Emergency physicians in urban settings will frequently encounter patients not known to be HCV positive and not identified as such. These results emphasize the need for more effective preventive measures in the community and the importance of observing standard (universal) precautions in ED practice.

The INSTI HIV-1/HIV-2 antibody test: a review

INTRODUCTION

Rapid HIV tests have been widely adopted globally as an important component of HIV prevention and control programs. The INSTI™ HIV-1/HIV-2 antibody test is a second-generation HIV antibody test, available in most countries for use from whole blood, serum, and plasma.

AREAS COVERED

Available data on kit characteristics and current performance data on the INSTI™ HIV-1/HIV-2 antibody test are presented together with six other rapid point-of-care tests (RPOCTs) for HIV antibody. Few published data are available providing direct comparisons of INSTI™ with other RPOCTs for HIV antibody and standard laboratory-based HIV-1/HIV-2 antibody assays. Existing data showed that INSTI™ has comparable performance to other RPOCTs but detected seroconversion later than standard laboratory-based assays.

EXPERT OPINION

The good performance of INSTI HIV-1/HIV-2 antibody test, its ease of use, the rapid availability of results (< 5 min), and the lack of specialized equipment required to use the kit make this kit a useful addition to the global market. The unique antigen and flow through technology contained in the kit make it a strong addition to HIV RPOCTs and to rapid/rapid algorithms used in many resource-limited settings.

Circulating antibody free light chains and risk of posttransplant lymphoproliferative disorder

Posttransplant lymphoproliferative disorder (PTLD) is a major complication of solid-organ transplantation. With human immunodeficiency virus infection (an analogous immunosuppressive state), elevated kappa and lambda immunoglobulin free light chains (FLCs) in peripheral blood are associated with increased risk of lymphoma. To assess the role of B-cell dysfunction in PTLD, we measured circulating FLCs among Canadian transplant recipients, including 29 individuals with PTLD and 57 matched transplant recipients who were PTLD-free. Compared with controls, PTLD cases had higher kappa FLCs (median 1.53 vs. 1.07 times upper limit of normal) and lambda FLCs (1.03 vs. 0.68). Using samples obtained on average 3.5 months before PTLD diagnosis, cases were more likely to have polyclonal FLC elevations (i.e. elevated kappa and/or lambda with normal kappa/lambda ratio: odds ratio [OR] 4.2, 95%CI 1.1-15) or monoclonal elevations (elevated kappa and/or lambda with abnormal ratio: OR 3.0, 95%CI 0.5-18). Strong FLC-PTLD associations were also observed at diagnosis/selection. Among recipients with Epstein-Barr virus (EBV) DNA measured in blood, EBV DNAemia was associated with FLC abnormalities (ORs 6.2 and 3.2 for monoclonal and polyclonal elevations). FLC elevations are common in transplant recipients and associated with heightened PTLD risk. FLCs likely reflect B-cell dysfunction, perhaps related to EBV-driven lymphoproliferation.

Factors associated with vaccine failure and vertical transmission of hepatitis B among a cohort of Canadian mothers and infants

Mother-to-child transmission of hepatitis B virus (HBV) continues to occur despite immunoprophylaxis. We examined maternal factors contributing to transmission in infants receiving adequate immunoprophylaxis in Alberta, Canada. Prenatal specimens from HBsAg-positive women whose babies developed HBV infection despite immunoprophylaxis (cases) and HBsAg-positive mothers whose babies did not (controls) were tested for HBsAg, HBeAg and HBV DNA. Specimens with detectable DNA underwent HBV genotyping. Routinely collected surveillance data and laboratory test results were compared between cases and controls. Twelve cases and 52 controls were selected from a provincial registry from 2000 to 2005. At the time of prenatal screening, median maternal age was 31 years [interquartile range (IQR): 27.5-34.5], and median gestational age was 12 weeks (IQR 10.0-15.5). Cases were more likely than controls to test positive for HBeAg (77.8% vs. 23.1%; P < 0.05). Of all mothers with detectable viral load (n = 51), cases had a significantly higher median viral load than did controls (5.6 × 10(8)  IU/mL vs. 1750 IU/mL, P < 0.0001). Of the two cases who were HBeAg negative, one had an undetectable viral load 8 months prior to delivery and a sP120T mutation. The viral load in the other case was 14,000 IU/mL. The majority of isolates were genotype B (31.3%) and C (31.3%) with no significant differences in genotype between cases or controls. In this case-control study, transmission of HBV to infants was more likely to occur in mothers positive for HBeAg and with high HBV DNA.

DIAL: A Platform for real-time Laboratory Surveillance

Laboratory information systems fulfill many of the requirements for individual result management within a public health laboratory. However, access to the systems by data users, timely data extraction, integration, and data analysis are difficult tasks. These difficulties are further complicated by often having multiple laboratory results for specific analytes or related analytes per specimen tested as part of complex laboratory algorithms requiring specialized expertise for result interpretation. We describe DIAL, (Data Integration for Alberta Laboratories), a platform allowing laboratory data to be extracted, interpreted, collated and analyzed in near real-time using secure web based technology, which is adapted from CNPHI's Canadian Early Warning System (CEWS) technology. The development of DIAL represents a major technical advancement in the public health information management domain, building capacity for laboratory based surveillance.

Nucleic acid testing (NAT) of organ donors: is the 'best' test the right test? A consensus conference report

Nucleic acid testing (NAT) for HIV, HBV and HCV shortens the time between infection and detection by available testing. A group of experts was selected to develop recommendations for the use of NAT in the HIV/HBV/HCV screening of potential organ donors. The rapid turnaround times needed for donor testing and the risk of death while awaiting transplantation make organ donor screening different from screening blood-or tissue donors. In donors with no identified risk factors, there is insufficient evidence to recommend routine NAT, as the benefits of NAT may not outweigh the disadvantages of NAT especially when false-positive results can lead to loss of donor organs. For donors with identified behavioral risk factors, NAT should be considered to reduce the risk of transmission and increase organ utilization. Informed consent balancing the risks of donor-derived infection against the risk of remaining on the waiting list should be obtained at the time of candidate listing and again at the time of organ offer. In conclusion, there is insufficient evidence to recommend universal prospective screening of organ donors for HIV, HCV and HBV using current NAT platforms. Further study of viral screening modalities may reduce disease transmission risk without excessive donor loss.

The feasibility of using an 'opt-out' approach to achieve universal HIV testing of tuberculosis patients in Alberta

OBJECTIVE

Universal HIV testing of tuberculosis (TB) patients, defined as testing greater than 80% of incident cases, has been recommended but not achieved in Canada. The objectives of this study were: i) to assess the success of an 'opt-out' approach, whereby HIV testing is routine unless the patient specifically chooses otherwise, and ii) to determine the risk factors for HIV in patients tested before and after this approach was implemented.

METHODS

TB and HIV databases in the province of Alberta were cross-matched before HAART (highly active anti-retroviral therapy) was available (1991-1997), after HAART but before 'opt-out' testing was implemented (1998-2002), and after 'opt-out' testing was implemented (2003-2006), and the HIV status of TB patients in each time period was described. The demographic and clinical characteristics of HIV-positive and -negative TB patients aged 15-64 years were compared.

RESULTS

HIV testing of TB patients increased from 11.5% before HAART, to 44.9% after HAART but before 'opt-out' testing, to 81.9% after 'opt-out' testing was implemented. Between 1991 and 2006, 50 TB patients were diagnosed with HIV co-infection, all in the age group 15-64 years. Among TB patients aged 15-64 years who were HIV tested, those testing positive were significantly less likely to be female and to have respiratory TB and significantly more likely to have both respiratory and non-respiratory TB. The prevalence of HIV positivity in HIV-tested TB patients aged 15-64 years was 7.4% in 2003-2006.

CONCLUSION

Universal HIV testing of TB patients is achievable through 'opt-out' HIV testing.

A commutable cytomegalovirus calibrator is required to improve the agreement of viral load values between laboratories

BACKGROUND

Viral load testing for cytomegalovirus (CMV) is an important diagnostic tool for the management of transplant recipients and immunocompromised individuals; however, inconsistency among laboratories in quantitative measurements of viral load limits interinstitutional comparisons. These inconsistencies stem from the lack of assays cleared by the US Food and Drug Administration, the absence of international standards, the wide variety of CMV-extraction and -detection methods, and differences in materials used for calibration. A critical component of standardization is the use of calibrators that are traceable and commutable.

METHODS

Bland-Altman plots and prediction ellipses were used to test the commutability of 2 CMV calibrators for 2 different quantification methods.

RESULTS

Tests with 2 methods showed 1 calibrator to be commutable and the other to be noncommutable. The results for the commutable calibrator were within the 95% prediction interval of the clinical samples in the Bland-Altman plot and within the 95% prediction ellipse for a simulated commutable calibrator, whereas the results for the noncommutable calibrator were not within these prediction intervals. When used to calibrate patient results, only the commutable calibrator, the OptiQuant CMV(tc) Calibration Panel, significantly improved the comparability of viral loads for the 2 different measurement methods.

CONCLUSIONS

This study demonstrates that an important goal in the effort to improve healthcare for patients with CMV-related disease is the establishment of traceable and commutable reference materials, including both calibrators and controls. .

Cell-mediated immunity to predict cytomegalovirus disease in high-risk solid organ transplant recipients

Late-onset cytomegalovirus (CMV) disease commonly occurs after discontinuation of antiviral prophylaxis. We determined the utility of testing CD8+ T-cell response against CMV as a predictor of late-onset CMV disease after a standard course of antiviral prophylaxis. Transplant patients at high-risk for CMV disease were enrolled. CD8+ T-cell-mediated immunity (CMI) was tested using the QuantiFERON-CMV assay at baseline, 1, 2 and 3 months posttransplant by measurement of interferon-gamma response to whole blood stimulation with a 21-peptide pool. The primary outcome was the ability of CMI testing to predict CMV disease in the first 6 months posttransplant. There were 108 evaluable patients (D+/R+ n = 39; D-/R+ n = 34; D+/R- n = 35) of whom 18 (16.7%) developed symptomatic CMV disease. At the end of prophylaxis, CMI was detectable in 38/108 (35.2%) patients (cutoff 0.1 IU/mL interferon-gamma). CMV disease occurred in 2/38 (5.3%) patients with a detectable interferon-gamma response versus 16/70 (22.9%) patients with a negative response; p = 0.038. In the subgroup of D+/R- patients, CMV disease occurred in 1/10 (10.0%) patients with a detectable interferon-gamma response (cutoff 0.1 IU/mL) versus 10/25 (40.0%) patients with a negative CMI, p = 0.12. Monitoring of CMI may be useful for predicting late-onset CMV disease.

Screening of organ and tissue donors for West Nile virus by nucleic acid amplification--a three year experience in Alberta

West Nile Virus (WNV)-specific nucleic acid amplification testing (NAAT) of organ and tissue donors remains controversial. We report three years of WNV donor screening in Alberta Canada using NAAT. Between 2003 and 2005, 1549 initial specimens were received. A valid negative result was issued within the specified turnaround time on 1531 (98.8%). The initial NAAT was successful for 1393 samples (90%), while repeat testing using an alternate NAAT resolved a further 126 samples. For 12 of 14 donors, a second specimen provided a valid negative result. Failure to generate a valid negative result in time resulted in rescheduling of one living related organ transplant, and surgery proceeded in the absence of a final result in one multi-organ donation after risk assessment. For 11 tissue donors, tissues were discarded due to lack of a WNV result. Invalid results usually occurred on postmortem haemolyzed tissue donor samples due to inhibitory reactions. There were no confirmed positive donors, no false-positive results and no solid organs lost due to WNV testing. We conclude that WNV NAAT of organ and tissue donors can be implemented without compromising availability of donors but requires committed laboratory support.

Comparison of quantiferon-TB gold with tuberculin skin test for detecting latent tuberculosis infection prior to liver transplantation

Screening for latent tuberculosis infection (LTBI) is recommended prior to organ transplantation. The Quantiferon-TB Gold assay (QFT-G) may be more accurate than the tuberculin skin test (TST) in the detection of LTBI. We prospectively compared the results of QFT-G to TST in patients with chronic liver disease awaiting transplantation. Patients were screened for LTBI with both the QFT-G test and a TST. Concordance between test results and predictors of a discordant result were determined. Of the 153 evaluable patients, 37 (24.2%) had a positive TST and 34 (22.2%) had a positive QFT-G. Overall agreement between tests was 85.1% (kappa= 0.60, p < 0.0001). Discordant test results were seen in 12 TST positive/QFT-G negative patients and in 9 TST negative/QFT-G positive patients. Prior BCG vaccination was not associated with discordant test results. Twelve patients (7.8%), all with a negative TST, had an indeterminate result of the QFT-G and this was more likely in patients with a low lymphocyte count (p = 0.01) and a high MELD score (p = 0.001). In patients awaiting liver transplantation, both the TST and QFT-G were comparable for the diagnosis of LTBI with reasonable concordance between tests. Indeterminate QFT-G result was more likely in those with more advanced liver disease.

Automated screening using microfluidic chip-based PCR and product detection to assess risk of BK virus-associated nephropathy in renal transplant recipients

The cost-effective detection of viral particles in bodily fluids could enable more effective responses to viral outbreaks, whether isolated clinical cases, or influenza epidemics. In renal transplant recipients, complications arising from high levels of BK virus can lead to graft dysfunction, graft loss, and/or reduced patient survival. We describe a microfluidic system for the sensitive analysis of BK virus (viral load) in unprocessed urine samples that are applied directly onto the chip, thus avoiding labor-intensive processing and sources of inter-assay variability. Integration of small volume genetic amplification (PCR) and electrophoretic analysis detects as few as 1-2 viral copies, distinguishes between high, medium and low levels of virus and reliably identifies viral loads requiring clinical intervention. As a first step to wider application in the clinic and in the field, the present work presents an entirely microchip-based system, validated against conventional clinical methods using clinical samples.

Assessment of adenovirus infection in adult lung transplant recipients using molecular surveillance

BACKGROUND

Little is known about adenovirus infections in adult lung transplant recipients. Because the virus can establish latency, re-activation may be relatively common after transplantation.

METHODS

We assessed adenovirus infection in 80 adult lung transplant recipients. Adenovirus polymerase chain reaction (real-time PCR assay; limit of detection approximately 25 copies/ml plasma) was done on plasma samples collected at regular intervals until 1 year post-transplant.

RESULTS

Adenovirus DNA was detected in 18 of 80 patients (22.5%) and in 19 of 595 (3.4%) plasma samples up to 12 months post-transplant. Median time to detection of viremia was 134 days post-transplant (range 1 to 370 days). Median viral load was 180 copies/ml plasma (range 50 to 360 copies/ml). Symptoms were evaluated at the time of adenovirus detection: 14 of 18 (78%) patients were asymptomatic; 4 of 18 (22%) patients had otherwise unexplained febrile/flu-like illness that resolved spontaneously. Adenovirus was not found to be a trigger for acute rejection. No detrimental effect on pulmonary function was seen immediately after adenovirus infection.

CONCLUSIONS

Adenovirus viremia is common in adult lung transplant recipients. In contrast to findings on adenoviral pneumonitis in lung transplant recipients, isolated episodes of low-level viremia are self-limited and do not trigger acute rejection or a decline in pulmonary function.

International trial of the Edmonton protocol for islet transplantation

BACKGROUND

Islet transplantation offers the potential to improve glycemic control in a subgroup of patients with type 1 diabetes mellitus who are disabled by refractory hypoglycemia. We conducted an international, multicenter trial to explore the feasibility and reproducibility of islet transplantation with the use of a single common protocol (the Edmonton protocol).

METHODS

We enrolled 36 subjects with type 1 diabetes mellitus, who underwent islet transplantation at nine international sites. Islets were prepared from pancreases of deceased donors and were transplanted within 2 hours after purification, without culture. The primary end point was defined as insulin independence with adequate glycemic control 1 year after the final transplantation.

RESULTS

Of the 36 subjects, 16 (44%) met the primary end point, 10 (28%) had partial function, and 10 (28%) had complete graft loss 1 year after the final transplantation. A total of 21 subjects (58%) attained insulin independence with good glycemic control at any point throughout the trial. Of these subjects, 16 (76%) required insulin again at 2 years; 5 of the 16 subjects who reached the primary end point (31%) remained insulin-independent at 2 years.

CONCLUSIONS

Islet transplantation with the use of the Edmonton protocol can successfully restore long-term endogenous insulin production and glycemic stability in subjects with type 1 diabetes mellitus and unstable control, but insulin independence is usually not sustainable. Persistent islet function even without insulin independence provides both protection from severe hypoglycemia and improved levels of glycated hemoglobin. (ClinicalTrials.gov number, NCT00014911 [ClinicalTrials.gov].).

Clinical utility of commercial enzyme immunoassays during the inaugural season of West Nile virus activity, Alberta, Canada

West Nile virus (WNV) has spread rapidly across North America, creating a need for rapid and accurate laboratory diagnosis on a large scale. Immunoglobulin M (IgM) capture enzyme immunoassays (EIA) became commercially available in the summer of 2003, but limited data are available on their clinical performance. Consolidated human WNV diagnostic testing for the province of Alberta, Canada, at the public health laboratory permitted a large-scale evaluation of the assays, covering a wide clinical spectrum. Two thousand nine hundred sixty-nine sera were tested, from 2,553 Alberta residents, and 266 cases were identified. Sensitivities of the Focus assay and first-generation Panbio IgM capture EIA were 79 and 80%, respectively. During the first week of illness only 53 to 58% of cases were positive, but sensitivity was 96 to 97% after day 8. Sensitivity for neurological cases was 92% overall. Specificity was high for the Focus kit at 98.9%, but only 82.9% for the first Panbio kit. A positive Focus WNV IgG result with a twofold rise in IgG index was a reliable indicator of acute flavivirus infection (67/67 WNV). Agreement between the IgG test and hemagglutinin inhibition titers in paired sera was at least 82%. Commercial IgM and IgG EIA proved useful for WNV diagnosis, provided follow-up sera were collected after 8 days of illness.

A trial of valganciclovir prophylaxis for cytomegalovirus prevention in lung transplant recipients

Cytomegalovirus (CMV) infection is common after lung transplantation. We performed a prospective trial of valganciclovir prophylaxis in lung recipients with outcomes compared to matched historical controls. The valganciclovir group (n = 40) (including D+/R- and R+ patients) was prospectively enrolled, and received oral valganciclovir 900 mg once daily for 12 weeks. Historical controls (n = 40) received 12 weeks of daily intravenous ganciclovir if D+/R- or 12 weeks of oral ganciclovir if R+. CMV viral load testing was done at two-week intervals until 6 months posttransplant. Baseline demographics and immunosuppression were comparable in the two groups. The incidence of CMV viremia was 16/40 (40.0%) in the valganciclovir arm versus 18/40 (45%) in the ganciclovir arm (p = NS). The incidence of symptomatic CMV disease was 8/40 (20%) versus 7/40 (17.5%), respectively (p = NS). In both groups viremia, while on prophylaxis, was uncommon (valganciclovir: 0/40 and ganciclovir: 2/40). Peak viral load and time to viremia were similar in the two arms. High rates of viremia and symptomatic disease occurred in the D+/R- patients after discontinuation of prophylaxis. Genotypic CMV sequence analysis demonstrated low rates of ganciclovir resistance in both groups. Valganciclovir prophylaxis had similar efficacy to either intravenous ganciclovir (D+/R- patients), or oral ganciclovir (R+ patients) in lung recipients.

Severe chronic active Epstein-Barr virus infection mimicking steroid-dependent inflammatory bowel disease

Severe chronic active Epstein-Barr virus infection is a rare, debilitating, nonneoplastic, inflammatory disorder for which there is no definitive treatment. We describe a Caucasian child who initially presented with clinical and histopathologic features consistent with inflammatory bowel disease, for whom additional investigations led to the diagnosis of severe chronic active Epstein-Barr virus infection.

Hepatitis C seroprevalence and risk behaviors in patients attending sexually transmitted disease clinics

BACKGROUND

Hepatitis C virus (HCV) is a major global problem, transmitted primarily by percutaneous exposure to contaminated blood.

GOAL

The goal of the study was to determine the seroprevalence of and risk factors for HCV among patients attending two urban STD clinics in Alberta.

STUDY DESIGN

Anonymous unlinked serosurveys were performed with use of leftover sera. Self-administered questionnaires collected information on demographics, sexual behaviors, and drug use.

RESULTS

The seroprevalence of HCV was 3.4% (209 of 6,668 patients). Univariate analysis revealed that infection was higher among nontherapeutic needle users (RR = 80.9), those coinfected with HIV (RR = 8.09), individuals over the age of 20 years (RR = 6.68), those of aboriginal ethnicity (RR = 5.54), those with a history of STD (RR = 3.43), men (RR = 2.2), and bisexuals (RR = 2.23). Not utilizing condoms and engaging in prostitution or exchanging money or drugs for sex were also risk factors. In multivariate analysis, nontherapeutic needle use remained highly significant (RR = 60.54-65.51). Other significant factors included sex, age, ethnicity, a history of STD, and HIV infection (RR = 1.72, 4.62, 3.18, 1.69, and 2.56, respectively). Sexual orientation and sexual practices were not significant without a history of drug use.

CONCLUSION

Nontherapeutic needle use is the strongest predictor of HCV infection.

Hantavirus pulmonary syndrome in northern Alberta, Canada: clinical and laboratory findings for 19 cases

We reviewed the clinical and laboratory findings for 19 cases of hantavirus pulmonary syndrome (HPS) identified either serologically or by immunohistochemical testing of archival tissue at our tertiary care center. Fever (95%), cough (89%), and dyspnea (89%) were the most common presenting symptoms. The most prevalent presenting signs were respiratory abnormalities (95%) and tachycardia (84%). Common laboratory findings included thrombocytopenia (95%) and leukocytosis (79%). Elevated aspartate aminotransferase and lactate dehydrogenase levels were found in all patients tested. Intubation was required in 58% of the patients, and inotropic support was required in 53%. Our study confirms that serological responses appear early during clinical illness, making the enzyme immunoassay a useful tool for the diagnosis of acute HPS. The mortality (26%) and severity of disease that we observed among patients with HPS appear to be less than those reported elsewhere.

Permissive cytomegalovirus infection of primary villous term and first trimester trophoblasts

Forty percent of women with primary cytomegalovirus (CMV) infections during pregnancy infect their fetuses with complications for the baby varying from mild to severe. How CMV crosses the syncytiotrophoblast, the barrier between maternal blood and fetal tissue in the villous placenta, is unknown. Virus may cross by infection of maternal cells that pass through physical breaches in the syncytiotrophoblast or by direct infection of the syncytiotrophoblast, with subsequent transmission to underlying fetal placental cells. In this study, we show that pure (>99.99%), long-term and healthy (>3 weeks) cultures of syncytiotrophoblasts are permissively infected with CMV. Greater than 99% of infectious progeny virus remained cell associated throughout culture periods up to 3 weeks. Infection of term trophoblasts required a higher virus inoculum, was less efficient, and progressed more slowly than parallel infections of placental and human embryonic lung fibroblasts. Three laboratory strains (AD169, Towne, and Davis) and a clinical isolate from a congenitally infected infant all permissively infected trophoblasts, although infection efficiencies varied. The infection of first trimester syncytiotrophoblasts with strain AD169 occurred at higher frequency and progressed more rapidly than infection of term cells but less efficiently and rapidly than infection of fibroblasts. These results show that villous syncytiotrophoblasts can be permissively infected by CMV but that the infection requires high virus titers and proceeds slowly and that progeny virus remains predominantly cell associated.

Antimicrobial prophylaxis for open heart operations

Between 1986 and 1988, 450 adults undergoing coronary artery bypass, cardiac valve replacement, or both were enrolled into a prospective, randomized, comparative trial of cephalothin versus cefamandole as perioperative prophylaxis. They were assessed during their hospitalization and at 6 weeks and 6 months after discharge for postoperative infectious complications. Eleven patients had major postoperative infections including 5 with sternal wound infections (three bacteremic), 6 with bacteremia, 1 with prosthetic valve endocarditis, and 3 with severe venous donor graft site infections. Eight major infections occurred in patients receiving cephalothin prophylaxis and three in patients receiving cefamandole, with all five sternal wound infections occurring in the cephalothin group. Postoperative pathogens responsible for the major infections included gram-negative aerobes in 5 patients, Staphylococcus aureus in 4, and Staphylococcus epidermidis in 2. Preoperative colonizing staphylococcal isolates were not predictive of postoperative staphylococcal pathogens. Although there was no statistically significant difference in rate of major postoperative infectious complications using either cephalothin or cefamandole prophylaxis, there was a trend in favor of cefamandole. Gram-negative aerobes are becoming increasingly important pathogens in this setting.