Evaluation of serological screening of cadaveric sera for donor selection for cornea transplantation

Serological testing for infectious diseases markers of donor specimens from 24 h after death show no significant change in outcomes from other specimens

There is increasing demand for organ and tissue donations to cater for a growing waiting list of recipients. Serological screening of donors remains the initial assessment upon which many decisions are made, particularly if donors are found to be seropositive. Multiple different platforms are now available, although the Abbott ARCHITECT platform assays are currently licensed globally for testing of blood collected at less than 15 h post-mortem. Compliance with the specified maximum collection times drastically decreases the number of eligible deceased donors, with ~ 70% more donations available if screened at up to 24 h post mortem. A large scale study on deceased donors was performed where blood was collected between 12 and 25 h post-mortem. A total of 194 cadaveric serological specimens were tested using the Abbott ARCHITECT analyser for Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), Hepatitis C Virus (HCV), Human T Lymphotropic Virus type I/II, and syphilis infection. The specificity, sensitivity, accuracy, reproducibility and influence of storage conditions were assessed for testing with Abbott ARCHITECT platform for HIV antigen/antibody Combo, HCV antibody, HBV surface antigen (HBsAg), HBV core antibody (HBcAb), HTLVI/II antibody (rHTLV-I/II), and Syphilis TP assays. There was no significant difference between testing of sera from living and cadaveric individuals in terms of assay specificity, sensitivity and accuracy. The findings show testing of human serum and plasma specimens collected up to 24 h post-mortem with these assays is acceptable and reflects host status accurately.

Analyse von Einflussfaktoren auf die Eignung von kornealem Spendergewebe in der LIONS Hornhautbank Saar-Lor-Lux, Trier/Westpfalz von 2006 bis 2016

Hintergrund und Ziel der Studie Vor dem Hintergrund des Missverhältnisses zwischen Hornhautverfügbarkeit und -bedarf war das Ziel der Studie, signifikante Einflussfaktoren auf die Eignung sowie die Verwerfungsgründe von kornealem Spendergewebe zu eruieren und damit die Rate verworfener Hornhäute langfristig zu reduzieren.

Patienten und Methoden 4140 Hornhäute von 2083 Spendern wurden zwischen 2006 und 2016 analysiert. Die untersuchten Einflussgrößen umfassten das Alter, das Geschlecht und die medizinische Vorgeschichte der Spender und Prozessierungsfaktoren wie die Post-mortem-Zeit. Die Daten wurden in eine Microsoft-Access-Datenbank übertragen und mittels logistischer Regressionsanalysen mit SPSS 20.0 statistisch ausgewertet. In einem multiplen Regressionsmodell wurden 6 Einflussfaktoren auf die Eignung des Spendergewebes analysiert. Alle Hornhäute, die nicht für eine elektive Keratoplastik infrage kamen, galten hierbei als ungeeignet.

Ergebnisse Ein hohes Spenderalter > 80 Jahre erwies sich im Vergleich zur Referenzgruppe der Spender < 40 Jahre als signifikant negative Einflussgröße auf die Eignung der Hornhaut (p = 0,001). Auch eine vorangegangene Kataraktoperation minderte signifikant die Eignung (p < 0,001). Männliche Hornhäute waren signifikant weniger geeignet als weibliche Hornhäute (p = 0,028). Ein Hypertonus in der Spendervorgeschichte (p = 0,612), eine vorangegangene Chemotherapie (p = 0,745) oder ein Diabetes mellitus (p = 0,321) zeigten keinen Einfluss auf die Eignung. Sepsis (p = 0,026) und Multiorganversagen (MOV; p < 0,001) als Todesursachen des Spenders resultierten in signifikant höheren Verwerfungsraten aufgrund von Kontamination des Kulturmediums. Hornhäute, bei denen die Blutentnahme mehr als 12 h seit Versterben des Spenders zurücklag, mussten signifikant häufiger wegen einer positiven Spenderserologie verworfen werden (p < 0,001).

Schlussfolgerungen Faktoren wie eine vorangegangene Kataraktoperation und ein hohes Spenderalter verringerten die Eignung des Spendergewebes. Ein Diabetes, ein Hypertonus und eine Chemotherapie in der Spendervorgeschichte zeigten keinen statistisch signifikanten Einfluss auf die Eignung. Todesursachen wie Sepsis und Multiorganversagen erhöhten die Kontaminationsrate des Kulturmediums. Eine postmortale Blutentnahme nach mehr als 12 h geht mit einem erhöhten Risiko für ein positives Serologieergebnis einher.

Validation of Spiked Postmortem Blood Samples from Cornea Donors on the Abbott ARCHITECT and m2000 Systems for Viral Infections

Background

Transplantation of human corneal tissue is associated with the potential risk of transmittance of viral infections. In accordance with European directives and federal laws, in Germany each tissue donor has to be tested for infectious diseases such as hepatitis B and C virus (HBV and HCV) and human immunodeficiency virus (HIV) infection. However, most of the currently available CE-marked serologic and nucleic acid screening systems are only validated for antemortem blood.

Methods

Twenty related and paired ante- and postmortem blood samples from cornea donors were obtained and subsequently analyzed for hepatitis B surface antigen (HBsAg), hepatitis B antibody (anti-HBc), anti-HCV, HCV RNA, anti-HIV-1/2, and HIV p24 Ag using Abbott test systems. The sera were also spiked with reference materials in concentrations giving low and high positivity for HBV, HCV, and HIV markers.

Results

The spiked ante- and postmortem sera from related donors showed similar results for HBsAg, anti-HBc, anti-HCV, HCV RNA, anti-HIV, and HIV p24 Ag, indicating a high stability of viral markers in cadaveric specimens. Three cornea donors had a medical history of HBV infection and revealed anti-HBc at similar levels in the ante- and postmortem sera. In addition, there was a single postmortem sample demonstrating a weak signal of anti-HIV-1 and HIV-1 p24 Ag. False-positive or false-negative results were not detected. The results obtained with the Abbott ARCHITECT analyzer and Abbott RealTime HCV PCR showed no significant differences.

Conclusion

The analyzed screening assays are suitable for the detection of infectious markers of HBV, HCV, and HIV at similar levels in spiked ante- and postmortem sera from cornea donors.

Evaluation of occult hepatitis B infection in tissue donors: a multicenter analysis in Spain

Traditionally, when antibody to the Hepatitis B core antigen (anti-HBc) and antibody to the Hepatitis B surface antigen (anti-HBs) are positive, the donor is considered suitable. However, the literature contains cases with this profile and circulating hepatitis B virus DNA. The aim of the study is to analyze the incidence of occult hepatitis B virus infection (OBI). Retrospective data were evaluated for deceased tissue donors in ten Tissue Establishments (Spain) during 2017. The data included demographic data and the serological markers for hepatitis B that each tissue establishment performed. A total number of 1933 tissue donors were evaluated. A total of 180 donors were excluded: 6 (0.3%) with Hepatitis B surface antigen (HBs positive), and 174 in which DNA testing was not performed. Anti-HBc was positive in 175 donors (10%), in which anti-HBs was negative in 30 (17.1%) and positive in 145 (82.9%). In total, 27 donors with DNA positive (1.5%) were found, of which 3 of 117 donors (1.7%) showed anti-HBc negative and anti-HBs positive (> 10 IU/ml), 4 of 30 donors (13.3%) showed anti-HBc positive and anti-HBs negative and 20 of 145 donors (13.8%) showed both anti-HBc and anti-HBs positive. The highest probability of finding DNA occurs when anti-HBc is positive, regardless of the presence of anti-HBs. In our study, the probability of OBI was 1.5%. The classic concept that when anti-HBc and anti-HBs are positive (even with a titer of over 100 IU/ml) the donor can be accepted should, therefore, be reconsidered, and DNA testing should be mandatory.

Human immunodeficiency virus in cadavers: A review

Millions of people are infected with human immunodeficiency virus (HIV); however, limited research focuses on post-mortem HIV detection. Post-mortem HIV testing is vital because medical records are not always available, and the HIV status can be unknown. The aims of this study were to review the available literature and determine the most efficient HIV test for post-mortem samples, the optimal tissue or bodily fluid to be tested, and the duration that HIV remains reliably detectable. A literature search was conducted using PubMed and Google Scholar. Terms were related to HIV (HIV detection, HIV testing, HIV prevalence) and deceased individuals (post-mortem, cadaver, deceased, organ donor). Inclusion criteria included English studies, or articles with at least an English abstract, while review articles were excluded. From this literature search, 43 studies were applicable. These studies most commonly used enzyme-linked immunosorbent assay and Western blot as screening and confirmation tests, respectively. As for the optimal tissue or bodily fluid, serum remained the golden standard, while testing skin seemed promising. HIV remains detectable in the body up to 58 days after death, although few studies tested samples after 48 h. Knowledge of the HIV status can be beneficial in the case of accidental exposure and can create a range of possible research opportunities on the effects of HIV in different organ systems. This review outlined several gaps in the current literature and future studies should investigate these gaps because this information can be relevant to numerous professions. Clin. Anat. 32:603-610, 2019. © 2019 Wiley Periodicals, Inc.

Factors affecting the serological testing of cadaveric donor cornea

Purpose:

The purpose of this study was to evaluate the serological profile of the eye donors and to study the influence of various factors on serological test results.

Methods:

A cross-sectional, observational study was conducted, and data of 509 donors were reviewed from the records of eye bank from December 2012 to June 2017. Various details of donors analyzed included the age, sex of the donor, cause of death, source of tissue, time since blood collection after death, macroscopic appearance of blood sample, and details of discarded tissues. Serological examination of blood was performed for human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus (HCV), venereal disease research laboratory (VDRL), and serology reports reactive or nonreactive were analyzed.

Results:

Among the 509 donors, 295 (58%) were male, and 420 (82.50%) belonged to age group ≥60 years. Most donors (354, 69.5%) died due to cardiac arrest. Macroscopically, sera were normal in the majority of 488 (95.9%) cases. Among 509 donors, 475 (93.3%) were nonreactive, 12 (2.4%) donors were found to be reactive to hepatitis B surface antigen (HBsAg), and 1 (0.2%) was reactive to HCV, but no donor serology was reactive to HIV or VDRL. Twenty-one (4.12%) donors’ sera were not fit for serological testing. Among all donors, 475 (93.32%) donors were accepted and 34 (6.67%) were rejected or discarded on the basis of serological testing. Cause of death and macroscopic aspect of sera influenced the serological results in a highly significant manner (P = 0.00). Acceptance or rejection of the donor was significantly influenced by the serological results of the donor (P = 0.00).

Conclusion:

The seroprevalence among eye donor for HBsAg and HCV was 12 (2.4%) and 1 (0.2%), respectively. Factors such as cause of death and macroscopic aspect of sera influence the serological results. Time since blood collection or sampling will not show any impact on viral serological results if postmortem sampling will be done in < 10 hours(h) after death which can improve the safety and utility of the donor cornea.

Detection of human immunodeficiency virus, hepatitis C virus, and hepatitis B virus in postmortem blood specimens using infectious disease assays licensed for cadaveric donor screening

BACKGROUND

Evaluation of assay performance on postmortem blood specimens (obtained after cessation of the heartbeat) presents unique scientific and regulatory challenges. In the United States, assay performance is evaluated in part by spiking postmortem specimens.

METHODS

Fifty-four specimens obtained from decedents known to be infected with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV), including some coinfections, were tested for each virus using Food and Drug Administration (FDA)-licensed donor screening tests for nucleic acid, antibody, and antigen.

RESULTS

For each disease, >95% of subjects who were reported to have an infection at the time of death had a positive test result on at least one of the donor screening assays for that infection.

CONCLUSION

Licensed donor screening tests were positive on postmortem specimens obtained within 24 hours of death from individuals dying with HIV, HCV, and/or HBV, and were able to detect presence of the virus. The use of multiple tests (including antibody and direct viral detection methods) is necessary to adequately evaluate donors.

Factors influencing the virological testing of cornea donors

To assess the influence of donor, environment, and logistical factors on the results of virological testing of blood samples from cornea donors.Data from 670 consecutive cornea donors were analyzed retrospectively. Logistic regression analysis was used to assess the influence of different factors on the results of virological testing of blood samples from cornea donors.The mean annual rate of donors with serology-reactive or not evaluable result was 14.8% (99 of 670) (range 11.9%-16.9%). The cause of donor death by cancer increased the risk of serology-reactive or not evaluable result (P = .0300). Prolonged time between death and post mortem blood removal was associated with a higher rate of serology-reactive or not evaluable result (P < .0001). Mean monthly temperature including warmer months, differentiating between septic and aseptic donors, sex, and donor age had no significant impact on the results of virological testing of blood samples from cornea donors.The cause of donor death by cancer and a prolonged time between death and post mortem blood removal seem to be mainly responsible for serology-reactive or not evaluable result of blood samples from cornea donors. The percentage of discarded corneas caused by serology-reactive or not evaluable result may be reduced by shortening the period of time between death and post mortem blood removal.

Prevalence of blood-borne viral infections among autopsy cases in Jordan

Background: Morgues are high risk areas for the spread of infection from cadavers to staff during the post-mortem examination. Infection can spread from corpses to workers by airborne transmission, by direct contact, or through needle and sharp object injuries. Objective: Knowledge about the prevalence of these infections on autopsy is essential to determine the risk of transmission and to further enforce safety measures. Methods: This is a descriptive study. All autopsies performed in the Department of Forensic Medicine at Jordan University Hospital during the study period were tested for the serology of human immunodeficiency, hepatitis B and C viruses. Positive tests were confirmed by nucleic acid testing. Results: A total of 242 autopsies were tested. Age ranged from 3 days to 94 years (median 75.5 years, mean 45.3 years (21.9 ±  SD)). There were 172 (71%) males. The cause of death was considered natural in 137 (56.6%) cases, accidental in 89 (36.8%), homicide in nine (3.7%), suicide in four (1.7%), and unknown in three (1.2%) cases. Hepatitis B surface antigen was positive in five (2.1%) cases. Hepatitis C virus antibody was positive in five (2.1%) cases and the hepatitis C virus polymerase chain reaction was positive in two (0.8%) cases. HIV antibody was not detected in any of the cases. The infection status of cases was not associated with age, sex, nationality, or cause of death. Conclusion: The study findings indicated that there is a low prevalence of virus-infected autopsies in Jordan. However, the risk of transmission remains a potential threat and therefore the necessary precautions should always be taken during autopsy.

HCV RNA Testing of Plasma Samples from Cornea Donors: Suitability of Plasma Samples Stored at 4 °C for up to 8 Days

BACKGROUND

The HCV RNA testing of potential cornea donors frequently relies on blood samples stored pre mortem. The recommended storage time of maximum 72 h frequently excludes a significant fraction of donors.

METHODS

The influence of storage time of EDTA plasma samples at 4 °C on the viral load measured with the Roche HCV Quantitative Test vs. 2.0 was evaluated for 43 samples from HCV-positive individuals.

RESULTS

The mean reduction of the viral load after 4 °C storage for 6-8 days was 0.46 log₁₀ IU/ml (range +0.17 to -1.66 log₁₀ IU/ml). After 1-3 days a mean loss of 0.19 log₁₀ IU/ml (range +0.30 to -1.41 log₁₀ IU/ml) and after 3-5 days of 0.32 log₁₀ IU/ml (range +0.36 to -1.81 log₁₀ IU/ml) was observed. In 23.3% of samples, a viral load reduction ≥ 1 log₁₀ IU/ml (1.0-1.81 log₁₀ IU/ml) was found after prolonged storage (5-8 days). In none of the samples did the HCV load fall below the detection limit.

CONCLUSION

Plasma storage for up to 8 days can quantitatively reduce the HCV RNA load, yet has no influence on the reliability of a qualitative HCV RNA detection by this ultrasensitive test to determine the HCV status of serologically negative cornea donors.

Signal amplification systems in immunoassays: implications for clinical diagnostics

Biomarkers in physiological specimens serve as useful sensors for clinical diagnosis. Accurate detection of specific markers is crucial for the diagnosis of disease, monitoring drug therapy and patient screening. In vitro immunoassays are probably the most common, simple and relatively inexpensive serological tools used in clinical laboratories for the diagnosis and management of disease. Despite continued efforts to improve the performance of immunoassays in the past three decades, there is a need for highly sensitive assays that can detect the lowest levels of disease markers with greater accuracy. This review summarizes recent advances made towards increasing the sensitivity of immunoassays by amplifying detection signals, with implications for the development of highly sensitive diagnostic systems; it also discusses the principles of related methodologies.

Virus NAT for HIV, HBV, and HCV in Post-Mortal Blood Specimens over 48 h after Death of Infected Patients - First Results

OBJECTIVE

According to EU regulations (EU directive 2006/17/EC), blood specimens for virologic testing in the context of post-mortal tissue donation must be taken not later than 24 h post mortem.

METHODS

To verify validity of NAT in blood specimens collected later, viral nucleic acid concentrations were monitored in blood samples of deceased persons infected with HIV (n = 7), HBV (n = 5), and HCV (n = 17) taken upon admission and at 12 h, 24 h, 36 h and 48 h post mortem. HIV and HCV RNA were quantified using Cobas TaqMan (Roche), HBV DNA was measured by in-house PCR.

RESULTS

A more than 10-fold decrease of viral load in samples taken 36 h or 48 h post mortem was seen in one HIV-infected patient only. For all other patients tested the decrease of viral load in 36-hour or 48-hour post-mortal samples was less pronounced. Specimens of 3 HIV- and 2 HBV-infected patients taken 24 h post mortem or later were even found to have increased concentrations (>10-fold), possibly due to post-mortem liberation of virus from particular cells or tissues.

CONCLUSION

Our preliminary data indicate that the time point of blood collection for HIV, HBV and HCV testing by PCR may be extended to 36 h or even 48 h post mortem and thus improve availability of tissue donations.

Comparative infectious serology testing of pre- and post-mortem blood samples from cornea donors

Defined serological blood tests of deceased cornea donors are required to minimize the risk of viral infections of a transplant recipient as much as possible. Haemolysis, autolysis and bacterial contamination, may produce significant changes of post-mortem blood samples, which may lead to false serological test results. Pre- and post-mortem findings from the same cornea donors of the University Tissue Bank of the Charité in the years 2004-2009 (n = 487) were retrospectively analyzed and compared. The test results from pre-mortem blood samples were defined as the reference for the post-mortem blood test. Of 487 cornea donors, there were a total of 21 cases (4.3%) with discrepancies between serological test results from pre- and post-mortem blood samples. Of these, 7 values referred to the HBsAg-testing, 3 to the anti-HBs-, 1 to the anti-HBcIgG + IgM-, 1 to the anti-HCV-, 4 to the anti-HIV 1/2- and 5 to the TPLA-findings. False negative results within post-mortem serology occurred in 4 of 487 cases (0.8%). False positive results within the post-mortem blood samples occurred at a much more frequent rate, with 17 of 487 cases (3.5%). Discrepancies between serological pre- and post-mortem blood tests occur mainly due to the use of non-validated test systems. Therefore, it seems reasonable to test pre- and post-mortem blood samples serologically, whenever possible, at the same time, regardless of the sample age. Positive results, regardless of the sample type, should always be retested with validated confirmation tests (e.g. NAT), in order to differentiate between false and true positive results.

Infectious disease screening of blood specimens collected post-mortem provides comparable results to pre-mortem specimens

Serology assays for standard screening are optimised for use with sera collected from living adults and children. Because of potential changes in the vascular compartments after death, methods used for screening sera from cadaveric organ donors need to be validated before testing these specimens. Serum was separated from blood collected from cadaveric donors within 24 h of death and biochemical parameters measured to detect dilution of protein and haemolysis. In order to demonstrate if any inhibitors that might interfere with the assays were present, pre and post-mortem specimens were spiked with aliquots of human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV), human T-cell Lymphotropic Virus (HTLV) and T. pallidum-positive sera. Comparison of serum from living subjects with serum obtained post-mortem showed that while the concentration of total protein decreased, concentrations of albumin, immunoglobulin G (IgG) and immunoglobulin M (IgM) remained unchanged. The degree of haemolysis, as measured by free haemoglobin, was within the limits accepted for the Architect analyser. Spiking of pre- and post-mortem specimens with aliquots of HIV, HCV, HBV, HTLV and T. pallidum-positive sera showed no statistical difference in the signal between pre-mortem and post-mortem results when tested on the Abbott Architect analyser. Positive results were obtained in each of a further nine subjects who had tested positive for HIV (n=1), HCV (n=8), HBV (n=1) on pre-mortem serological testing. These findings suggest that the sensitivity of the Abbott Architect serological screening tests is not significantly affected in specimens collected within 24 h of the cessation of life.

Tissue donation and virus safety: more nucleic acid amplification testing is needed

In tissue and organ transplantation, it is of great importance to avoid the transmission of blood-borne viruses to the recipient. While serologic testing for anti-human immunodeficiency virus (HIV)-1 and -2, anti-hepatitis C virus (HCV), hepatitis B surface antigen (HBsAg), anti-hepatitis B core antigen (HBc), and Treponema pallidum infection is mandatory, there is until now in most countries no explicit demand for nucleic acid amplification testing (NAT) to detect HIV, hepatitis B virus (HBV), and HCV infection. After a review of reports in the literature on viral transmission events, tissue-specific issues, and manufacturing and inactivation procedures, we evaluated the significance of HIV, HCV, and HBV detection using NAT  in  donors of various types of tissues and compared our results with the experiences of blood banking organizations. There is a significant risk of HIV, HCV, and HBV transmission by musculoskeletal tissues because of their high blood content and the high donor-recipient ratio. If no effective virus inactivation procedure for musculoskeletal tissue is applied, donors should be screened using NAT  for  HIV, HCV, and HBV. Serologically screened cardiovascular tissue carries a very low risk of HIV, HCV, or HBV transmission. Nevertheless, because effective virus inactivation is impossible (retention of tissue morphology) and the donor-recipient ratio may be as high as 1:10, we concluded that NAT  should be performed for HIV, HCV, and HBV as an additional safety measure. Although cornea allografts carry the lowest risk of transmitting HIV, HCV, and HBV  owing to corneal physiology, morphology, and the epidemiology of corneal diseases, NAT  for  HCV should still be performed. If the NAT  screening of a donor for HIV, HCV, and HBV is negative, quarantine storage of the donor tissue seems dispensable. In view of numerous synergistic effects with transfusion medicine, it would be advantageous for tissue banks to cooperate with blood bank laboratories in performing virological tests.

Analyses of the effects of collection and processing time on the results of serology testing of cadaveric cornea donors

Serologic testing results are one of the major reasons for discarding donor corneas. This study assessed the prevalence of serologic markers and the times of preanalytic steps. The prevalence of serologic markers in 705 cornea donors of the Lorraine region was studied. One hundred forty-one (20%) corneas were discarded on the basis of serologic testing. In a subsample of 180 consecutive cornea donors, data concerning the time of death, sampling, and serology testing were collected. When the time between death and sampling did not exceed 8 h (n = 122), immediate decantation (separation of serum from clot) led to less discarding of corneas than delayed decantation (2/46 [4.3%] discarded in the group with immediate decantation versus 13/76 [17.1%] discarded in the group with delayed decantation [P = 0.038]). For blood samples collected within 8 h of death, the rate of reactive results is significantly lower if samples are immediately decanted.

Testing the Donor

The transplantation of tissues from donor to recipient is a fundamental part of medicine today. A range of tissues including bone, skin, tendons, heart valves, corneas etc. are collected from suitable donors and transplanted into those patients for whom tissue transplant would have clinical benefit.

Serological Viral Testing of Cadaveric Cornea Donors

BACKGROUND

Cornea graft recipients are exposed to viral transmission from the donor. Cadaveric donor serum is often of poor quality and frequently yields falsely positive results in serological assays that may result in the graft being needlessly discarded.

OBJECTIVE

We examined the influence of the time of blood collection after death, and the macroscopic aspect of serum, on serological test results in cadaveric cornea donors.

METHODS

Five hundred sixty-five consecutive cadaveric cornea donors were systematically tested for serological markers of human immunodeficiency virus type 1 and 2, human T-cell leukemia virus type 1, hepatitis B and hepatitis C viruses (HCV). We studied the influence of the macroscopic aspect of the donor's serum and the time of blood collection after death on the results of serological testing and on the subsequent decision to use or discard the graft.

RESULTS

Twenty-one and a half percent of corneas were rejected on the basis of virological test results. We found significant relationships between the macroscopic aspect of serum at the time of testing and: (i) a positive, equivocal or discrepant result of immunoassays, for all markers except anti-HCV antibodies, (ii) non acceptance of cornea grafts, and (iii) the time of blood sampling after death.

CONCLUSIONS

The macroscopic aspect of postmortem blood samples is the best predictor of the specificity of serological testing in cornea donors. Serological results should be interpreted with care when serum is macroscopically abnormal, and cadaveric donors should not be sampled more than 12 hr after death.

Risk factors for infectious disease in corneal transplant screening

PURPOSE

To identify potential medical and behavioral risk factors associated with infectious disease seropositivity in potential corneal donors using an extensive questionnaire completed by the next of kin.

METHODS

Retrospective review of medical history and behavioral risk assessment questionnaire and microbiology data for potential corneal donors seropositive for hepatitis B, hepatitis C, human immunodeficiency virus, human T-cell leukemia virus and syphilis as compared to controls.

RESULTS

Tobacco use, cigarette smoking, chest pain and heart disease are each associated with corneal donor seropositivity (P < 0.05). Vaccination in the last twelve months is inversely associated with infectious disease (P < 0.05). Statistically significant factors associated with hepatitis C positive donors include: cigarette use, illicit drug use, chest pain, cardiac medications, kidney stones and lung disease (P < 0.05). Factors most often associated with transmission of this disease panel (such as intravenous drug use, sexual contact with prostitutes and history of blood transfusion) are often not identified by the next of kin in the questionnaire.

CONCLUSIONS

While there are questionnaire identified risk factors associated with seropositivity in this study, their clinical usefulness is unclear. Many factors crucial to the elimination of potentially infectious donor tissues are not identified in the posthumous history typically completed by next of kin. These questionnaires alone do not provide exclusion criteria for elimination of potentially infectious tissues from the donor pool.

Surveillance of HIV and viral hepatitis by analysis of samples from drug related deaths

OBJECTIVES

To determine the prevalence of antibodies against HIV, hepatitis B (HBV) and hepatitis C (HCV) in postmortem samples from drug related deaths (DRDs) in Denmark.

DESIGN

Prospective cohort study. Postmortem samples tested for anti-HIV, anti-HCV anti-HBc and anti-HBs. Comparison to pre-mortem testing when possible. DRDs were searched for in the national register of drug treatment, national prison registers, and the national infectious disease register.

SETTING

National level.

PARTICIPANTS

Drug related deaths admitted to Danish Institutes of Forensic Medicine during 2004.

MAIN OUTCOME MEASURES

Prevalence of antibodies, injection drug use, drug treatment experience and prevalence of cirrhosis.

RESULTS

Samples for analysis were obtained from 78% (233/299) of DRDs. The prevalences of anti-HIV, anti-HCV and anti-HBc were 4% (9/214), 51% (110/215), and 35% (74/209), indicating a persisting low prevalence of HIV and a declining prevalence of HCV and HBV. Injecting ever was detected among 45% of DRDs and this was associated with a significantly higher prevalence of hepatitis B and C. Among the DRDs 56% received drug treatment and 12% had cirrhosis at autopsy. Evidence of vaccination against HBV was found among 16% (21/128).

CONCLUSIONS

Monitoring of viral hepatitis and HIV among DRDs is feasible, and our survey indicates a falling prevalence among Danish drug users. Surveillance based on drug users in treatment may overestimate the true prevalence.

Prevalence of skin allograft discards as a result of serological and molecular microbiological screening in a regional skin bank in Italy

BACKGROUND

Postmortem skin is widely used in the treatment of patients with severe burns. Skin specimens must be screened for transmissible agents including human immunodeficiency virus (HIV), hepatitis B (HBV) and C (HCV) virus, human T-cell lymphotropic virus (HTLV), cytomegalovirus (CMV) and Treponema pallidum.

METHODS

Four hundred and sixty-one cadaveric donors underwent serological and molecular microbiological (polymerase chain reaction, PCR) screening at Siena Skin Bank between 2000 and 2004.

RESULTS

74/461 donors (16.1%) were found ineligible under current regulations.

CONCLUSIONS

These results are interesting in a local context and underline the importance of screening involving both routine serological procedures and molecular microbiological investigation. The latter has not been uniformly introduced in many countries and very limited data is available to assess its cost-benefit ratio in the field of skin donor screening.

Detection of hepatitis C virus antibodies and RNA among medicolegal autopsy cases in Northern France

Forensic medical personnel are at risk of exposure to blood-borne viruses including hepatitis C virus (HCV). The aim of this study was to determine prevalence of HCV markers among a cadaver population at the medicolegal institute in Lille. Seventy-seven consecutive cadavers were screened for antibodies to HCV and for HCV RNA. Positive results were confirmed by an immunoblot assay. Fifty-three cadavers had a histopathologic study. Anti-HCV was detected in 13 (16.9%) and accompanied by HCV RNA in 7 (9%) cases. The rate of HCV RNA detection among seropositive cases was 53.8%. Five cases had histopathologic lesions suggestive of hepatitis. This is the first HCV RNA screening in forensic cadavers. The results highlight the high prevalence rate of HCV cases in medicolegal practice in Lille. All forensic specimens should be treated as potentially infectious and universal precautions should be taken.

Preventing disease transmission by deceased tissue donors by testing blood for viral nucleic acid

Nucleic acid testing (NAT) has reduced the risk of transmitting infectious disease through blood transfusion. Currently NAT for HIV-1 and HCV are FDA licensed and performed by nearly all blood collection facilities, but HBV NAT is performed under an investigational study protocol. Residual risk estimates indicate that NAT could potentially reduce disease transmission through transplanted tissue. However, tissue donor samples obtained post-mortem have the potential to produce an invalid NAT result due to inhibition of amplification reactions by hemolysis and other factors. The studies reported here summarize the development of protocols to allow NAT of deceased donor samples with reduced rates of invalid results. Using these protocols, inventories from two tissue centers were tested with greater than 99% of samples producing a valid test result.

Role of nucleic acid testing in cadaver organ donor screening: detection of hepatitis C virus RNA in seropositive and seronegative donors

Hepatitis C virus (HCV) transmission by both seropositive and seronegative cadaver organ donors has been documented, yet nucleic acid testing is not routinely used to identify active infection in these donors prior to transplantation. Between November 2001 and February 2004, we screened 1445 cadaver organ donors for anti-HCV antibodies with either HCV EIA-2.0 (Abbott Diagnostics, Chicago, IL, USA) and/or Ortho HCV Version 3.0 ELISA (Ortho-Clinical Diagnostics, Raritan, NJ, USA) and confirmed seropositive samples with Chiron RIBA3.0 SIA (Chiron Corporation, Emeryville, CA, USA). Samples with sufficient volume (n = 726) were tested by the VERSANT HCV [transcription-mediated amplification (TMA)] Qualitative assay (Bayer Healthcare LLC, Tarrytown, NY, USA) which can be performed in approximately 5 h. Those with detectable HCV RNA and sufficient volume were quantified by the VERSANT HCV 3.0 (bDNA) Assay (Bayer Healthcare LLC) and/or the HCV RNA TMA Quantitative Assay (n = 23) and genotyped (n = 57). Seventy-seven of 1445 (5.3%) donors were seropositive, reactive by either one or both anti-HCV assays. Fifty-two of 63 (82.5%) of the seropositive samples had detectable HCV RNA and were genotyped. Seventeen of these samples had quantifications ranging from 128,123 to >7,692,307 IU/mL. Six of 663 (0.9%) seronegative samples had detectable HCV RNA. Their quantifications ranged from <9.3 to 1,464,799 IU/mL, and five of these six were successfully genotyped. As HCV RNA was demonstrated in samples from both our seropositive and seronegative cadaver organ donors, we are now incorporating nucleic acid testing into our donor screening/diagnostic algorithm.

Challenges in the Testing of Non-Heart-Beating Cadavers for Viral Markers: Implications for the Safety of Tissue Donors

Natural changes that occur in blood and tissue after death may result in false positive results in antigen and antibody detection tests performed to identify markers of viral infection in potential tissue donors. Such tissue, which might otherwise be acceptable for therapeutic purposes, would not meet current standards for safe tissue banking. This is especially important in the context of insufficiency in the tissue supply. In this study, a series of blood samples collected during routine post-mortem examination was assayed using a range of commercially available kits for the detection of HBsAg, anti-HCV and anti-HIV 1 + 2 antibody/antigen. Results of tests on 104 samples collected from 97 individuals indicate that some kits result in a higher number of initial reactive samples than others. Approximately 40% of samples were reactive in one or more HBsAg assay, less than 10% in at least one anti-HIV kit and only 1 sample at low level on an anti-HCV kit. Liver or lymph node samples from individuals whose serum sample gave reactive results in antigen/antibody assays were tested for viral nucleic acid in the corresponding nucleic acid amplification test. Only one individual's sample was confirmed to test positive for HBsAg in a confirmatory neutralisation test and by nucleic acid amplification technology, and a second individual whose serum was scored reactive for anti-HCV, but negative for HBsAg, had a liver sample which was HBV DNA positive and HCV RNA negative. The results of the study indicate that antibody/antigen assays are not as specific as NAT using state of the art DNA extraction techniques. Both types of assay complement each other and used together will help assure the safety of tissues for transplantation.

Design and construction of novel molecular conjugates for signal amplification (I): conjugation of multiple horseradish peroxidase molecules to immunoglobulin via primary amines on lysine peptide chains

Immunoconjugates are widely used for indirect detection of analytes (such as antibodies or antigens) in a variety of immunoassays. However, the availability of functional groups such as primary amines or free sulfhydryls in an immunoglobulin molecule is the limiting factor for optimal conjugation and, therefore, determines the sensitivity of an assay. In the present study, an N-terminal bromoacetylated 20 amino acid peptide containing 20 lysine residues was conjugated to N-succinimidyl-S-acetylthioacetate (SATA)-modified IgG or free sulfhydryl groups on 2-mercaptoethylamine (2-MEA)-reduced IgG molecules via a thioether (S[bond]CH(2)CONH) linkage to introduce multiple reactive primary amines per IgG. These primary amines were then covalently coupled with maleimide-activated horseradish peroxidase (HRP). The poly-HRP-antibody conjugates thus generated demonstrated greater than 15-fold signal amplification upon reaction with orthophenyldiamine substrate. The poly-HRP-antibody conjugates efficiently detected human immunodeficiency virus (HIV)-1 antibodies in plasma specimens with significantly higher sensitivity than conventionally prepared HRP-antibody conjugates in an HIV-1 solid-phase enzyme immunoassay and Western blot analysis. The signal amplification techniques reported here could have the potential for development of highly sensitive immunodiagnostic assay systems.

Screening of blood from potential organ and cornea donors for viruses

Prospective nucleic acid tests were carried out for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) using the COBAS Amplicor HIV-1 and HCV tests (Roche Diagnostics, Meylan, France) on potential organ (n=113) and cornea (n=368) donors in France to evaluate their performance and suitability for use as a complement to routine serological tests. Blood samples were collected from organ donors with preserved cardiac function after verification of cerebral death. Blood samples were collected from cornea donors post-mortem within 48 hr after death. An internal control was added to the samples before extraction to monitor each individual polymerase chain reaction (PCR). The nucleic acid tests were always interpretable in organ donors and negative in all except in 2 anti-HCV positive patients. One had an indeterminate HIV p24 antigen but was negative for HIV RNA. HIV and HCV RNA were not found in cornea donors with a negative serology but indeterminate molecular results were frequent in this group (17.6%). Cornea donors also gave significantly more (14.4%) indeterminate serological results than organ donors (1.8%) (P<0.001). This was due to the poor quality of the blood samples collected post-mortem. However, there was no correlation between indeterminate results of serological and molecular tests. There were 16/19 (84%) indeterminate serological results for HIV and 4/4 (100%) for HCV that were negative by PCR. Thus, nucleic acid tests could be useful for qualifying a donor whose serological results are indeterminate. The extraction procedures on post-mortem specimens and/or blood collection must be changed to improve the performance of nucleic acid tests.