Screening of blood from potential organ and cornea donors for viruses

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.

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.

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.

Effective serological and molecular screening of deceased tissue donors

A comprehensive and effective screening programme is essential to support the banking of tissues from deceased donors. However, the overall quality of the samples obtained from deceased donors, quantity and condition, is often not ideal, and this may lead to problems in achieving accurate and reliable results. Additionally a significant percentage of referrals are still rejected upon receipt as unsuitable for screening. We are actively involved in improving the overall quality of deceased donor screening outcomes, and have specifically evaluated and validated both serological and molecular assays for this purpose, as well as developing a specific screening strategy to minimise the specificity issues associated with serological screening. Here we review the nature and effectiveness of the deceased donor screening programme implemented by National Health Service Blood and Transplant (NHSBT), the organisation with overall responsibility for the supply of tissue products within England. Deceased donor screening data, serological and molecular, from August 2007 until May 2012 have been collated and analysed. Of 10,225 samples referred for serology screening, 5.5 % were reported as reactive; of 2,862 samples referred for molecular screening, 0.1 % were reported as reactive/inhibitory. Overall 20 % of the serological and 100 % of the molecular screen reactivity was confirmed as reflecting true infection. The use of a sequential serology screening algorithm has resulted in a marked reduction of tissues lost unnecessarily due to non-specific screen reactivity. The approach taken by NHSBT has resulted in the development of an effective and specific approach to the screening of deceased tissue donors.

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.

Validation of Virus NAT for HIV, HCV, HBV and HAV Using Post-Mortal Blood Samples

OBJECTIVE

Commercial available NAT systems are usually not validated for screening of post-mortem blood samples. NAT testing might be challenging due to inhibitory substances in the cadaveric blood sample that cause false-negative test results. Validation studies have to be performed to show the performance characteristics of the NAT assays for testing cadaveric blood.

METHODS

A set of 32 post-mortem serum and plasma samples from cornea donors and 40 control samples from blood donors, serologically and NAT negative for all investigated parameters, were spiked with defined concentrations of WHO reference material and tested for HIV-1, HCV, HBV, and HAV by NAT using DRK Baden-Württemberg-Hesse CE PCR kits. Analytical sensitivity, analytical specificity and reproducibility/precision were validated and compared with each other in both groups of samples.

RESULTS

The analytical sensitivity was 100% for control and post-mortem specimens when spiked with virus standards at concentrations of 3 × level of detection (LOD). Invalid results did not occur. The analytical specificity rate for all assays was 100%. Intra-assay variation was analyzed as a function of sample material and sampling time post mortem. Values of % coefficient of variation (%CV) were comparable for serum and plasma but slightly higher for post-mortem samples especially for those samples collected more than 24 h post mortem.

CONCLUSION

Based on the presented validation, postmortem donor samples can be tested with the automated DRK Baden-Würtemberg-Hesse NAT system.

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.

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.

A novel real-time multiplex reverse transcriptase-polymerase chain reaction for the detection of HIV-1 RNA by using dual-specific armored RNA as internal control

OBJECTIVE

Transmission of HIV-1 and diagnosis of infection in hospitals and public health settings remains a worldwide concern. HIV-1 detection is sometimes not possible using current commercial assays, probably due to mismatches between the selected primers and probes.

METHODS

By screening primers and probes, we developed a dual-specificity probe real-time reverse transcriptase-polymerase chain reaction (DSPrtRT-PCR) assay using dual-specific armored RNA as the internal control. The specificity and sensitivity were compared between the monospecificity probe real-time and DSPrtRT-PCR techniques.

RESULTS

The sensitivity of DSPrtRT-PCR improved significantly, with no effect on its specificity. The detection limit was 173 IU/ml. All the HIV-1 group M and group O could be detected. In clinical assays, 1,000 copies/ml of armored RNA was required as internal control. When applied to negative samples, 100% specificity was achieved. Among 60 samples from the tested patients, DSPrtRT-PCR demonstrated high sensitivity, accurately detecting 50 positives and 10 negatives that were confirmed by the COBAS AmpliScreen assay.

CONCLUSION

DSPrtRT-PCR is a more efficient and effective viral assay with high sensitivity and specificity as compared to monospecificity probe PCR. It can be widely applied in blood donor screening and qualitative individual detection of HIV-1 RNA.

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.

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.

Failure and success of HIV tests for the prevention of HIV-1 transmission by blood and tissue donations

French blood banks recently implemented nucleic acid testing (NAT) of all blood donations to reduce the risk of HIV transmission during the pre-seroconversion period. For tissue donation, HIV infection screening relies on HIV p24 antigen and anti-HIV-1 and 2 antibody detection. In this report, two related cases of infectious donations are described from a cornea donor during the preseroconversion window who was infected by an HIV antibody and NAT negative blood donor. After investigation, the blood donor was found to be herself in the preseroconversion window. Two months after donation, she was found to be HIV positive. The residual risk of HIV infectious blood donations since NAT has been introduced is estimated to be lower than one out of 2.5 millions. Individual NAT instead of minipool testing would not increase significantly the blood transfusion safety. In contrast, introduction of NAT should be considered to increase tissue donation safety as soon as such screening will be possible technically.

Elimination of false-negative hepatitis C virus RNA results by removal of inhibitors in cadaver-organ donor blood specimens

Detection of viral nucleic acids in blood samples from cadavers is often difficult because of inhibition of the reverse transcriptase (RT) or polymerase chain reaction (PCR) steps by substances present in the samples. A robust method for the extraction and detection of hepatitis C virus (HCV) RNA from cadaver blood samples by polymerase chain reaction RT-PCR has been developed on the basis of the Qiagen QIAamp DNA mini kit extraction system (Basel, Switzerland). Twenty of 36 samples tested were positive for HCV RNA. Six of the 16 HCV-antibody- and RNA-negative samples contained inhibitors that were successfully removed by pretreatment of samples with the Qiagen AX matrix before extraction.

Evaluation of the clinical sensitivities of three viral load assays with plasma samples from a pediatric population predominantly infected with human immunodeficiency virus type 1 subtype G and BG recombinant forms

The viral load assays AMPLICOR HIV-1 Monitor Test 1.5, Nuclisens HIV-1 QT, and Quantiplex HIV RNA 3.0 (bDNA) were evaluated for their abilities to quantify human immunodeficiency virus type 1 (HIV-1) RNA in 64 plasma samples from 21 children infected in Portugal. The children were infected with HIV-1 subtypes A1, B, F1, G, and BG recombinant virus. AMPLICOR v1.5 and Quantiplex v3.0 detected all samples, and there was a good correlation of results between the two kits. Thirty-eight specimens containing HIV-1 subtype B, G, or recombinant BG, could not be detected by Nuclisens HIV-1 QT. We also evaluated the new Retina HIV-1 assay on 21 samples that were HIV-1 positive; Retina HIV-1 failed to detect 5 of 11 subtype G specimens. AMPLICOR v1.5 and Quantiplex v3.0 assays may be used for HIV-1 RNA quantification in Portugal, whereas an improvement in sensitivity for subtype G and recombinant BG is required for Nuclisens HIV-1 QT and Retina HIV-1.