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

The mediating role of anxiety in disease uncertainty and acute stress in acute ischaemic stroke patients in the post-epidemic era

Objective

To analyse the influencing factors of anxiety, disease uncertainty and acute stress response in patients with acute ischaemic stroke, and to verify the mediating role of anxiety in the post-epidemic era.

Methods

240 patients with acute ischaemic stroke were selected from a tertiary hospital in Wuhan City and investigated by questionnaire and convenience sampling methods.

Results

The total anxiety score, disease uncertainty and acute stress reaction were at moderate levels. Anxiety was positively correlated with illness uncertainty, and anxiety and acute stress response were negatively correlated. Multiple linear regression analysis showed that Sickness uncertainty, acute stress response, age, and work status influenced anxiety. Anxiety mediated the prediction of Sickness uncertainty and acute stress response, with the mediating effect accounting for 35.6% of the total effect.

Conclusion

Disease uncertainty in patients with acute ischaemic stroke in the post-epidemic era directly affects the acute stress response and indirectly through anxiety.

Scleral thinning causes, diagnosis, and management: A narrative review

INTRODUCTION

Sclera forms the outer fibrous coat of the eye and provides structural integrity for the housing of intraocular contents. Scleral thinning is a serious progressive condition which can lead to perforation and worsening visual functioning. This review aims to summarize the anatomical consideration and causes of scleral thinning, diagnosis, and the various surgical approaches available to treat scleral thinning.

MATERIALS AND METHODS

The narrative literature review was conducted by senior Ophthalmologists and researchers. PubMed, EMBASE, Web of Science, Scopus, and Google Scholar databases were searched for relevant literature from infinity till March 2022. Terms of the search referred to 'sclera' or 'scleral thinning' or 'scleral melting', and were combined with 'treatment', or 'management' or 'causes'. Publications were included in this manuscript if they offered information about the nature of these topics. Reference lists of relevant literature was searched. There were no limits on type of article to be included for this review.

RESULTS

Scleral thinning arises from diverse congenital, degenerative, immunological, infectious, post-surgical, and traumatic etiologies. It is diagnosed upon slit-lamp examination, indirect ophthalmoscopy, and optical coherence tomography. Conservative pharmacological treatment of scleral thinning may include anti-inflammatory drugs, steroid drops, immunosuppressors, monoclonal antibodies, and surgical treatments including tarsorrhaphy, scleral transplantation, amniotic membrane transplantation, donor corneal graft, conjunctival flaps, tenon's membrane flap, pericardial graft, dermis graft, cadaveric dura mater graft, and other autologous and biological grafts.

CONCLUSION

Scleral thinning treatments have developed dramatically in recent decades and the rise of alternative grafts for scleral transplantation procedures or use of conjunctival flaps have taken center stage in surgical management. This review adds a comprehensive summary of the scleral thinning with attention to the positive and negative features of new treatments alongside previous mainstay management strategies.

Infection and utilization rates of bone allografts in a hospital-based musculoskeletal tissue bank in north India

BACKGROUND

The bone bank unit of interest in this article was established in January 2018, in a tertiary care teaching institute of north India. Aim of this article is to describe the sources of allografts obtained, discard rates of allografts and infection rates in the recipients after use.

MATERIAL AND METHODS

All the relevant details of donors and recipients were maintained, and donors were screened for standard inclusion and exclusion criteria before obtaining the grafts. Aerobic culture was performed before storage and just prior to use. Samples with incomplete documentation, incomplete donor screening or positive cultures were discarded. Data on surgical site infection in recipients was collected from hospital records retrospectively. Initially ELISA based serological tests were used for screening. Donor has to undergo these tests again after 6 months to account for the window period of proliferation of viruses. Nucleic acid amplification tests (NAAT) for these viral agents were introduced in the hospital in May 2018.

RESULTS

Allografts from a total of 196 donors were obtained in the bone bank over 2 years. Major source of bone was femoral heads harvested during total hip arthroplasty or hemi-arthroplasty. 44(22.4%) grafts had to be discarded. 95 allografts were used in 88 patients during this time. Most common indication for use was surgery for bone tumors (40%), followed by complex primary or revision arthroplasty (30.5%). Three (3.4%) recipients developed deep infection postoperatively.

CONCLUSION

Frozen allograft bone from hospital based bone banks is a reliable source of allografts. When meticulous precautions for sterility are followed, risk of infection is low. Monitoring of such bone banks should fall within a framework of the local legislature. Incomplete documentation is the major reason for wastage of the samples obtained. NAAT may be useful in screening of donors, as it reduces the wastage and the holding time of the allografts.

Detection of Epstein-Barr virus by a rapid and simple accelerated denaturation bubble-mediated strand exchange amplification method

Epstein-Barr Virus (EBV) is a tumor-associated virus naturally transmitted through saliva. This virus is the pathogen of infectious mononucleosis, which is closely related to the occurrence of nasopharyngeal carcinoma (NPC) and childhood lymphoma. Although a majority of EBV infected individuals exhibited good tolerance after primary infection, those who carry a viral load greater than the clinical cutoff value (COV), the upper level in healthy carriers, still suffer a high risk of cancer. Herein, a simple, rapid, and effective method, accelerated strand exchange amplification (ASEA), was developed for EBV detection, which could offer a strategy for non-invasive testing of EBV in saliva samples instead of blood samples as in traditional serology based methods and avoid bleeding during diagnosis. This approach could distinguish the genomic DNA of EBV and other species in saliva, and its limit of detection was as low as 1000 copies per mL, which was lower than the COV of EBV. Moreover, DNA extracted from saliva samples (n = 50) was employed as a template for EBV detection via qPCR and ASEA, the result of which showed that ASEA exhibited comparable sensitivity and specificity for actual sample diagnosis. Additionally, similar to conventional PCR, this method requires only one pair of primers and could be performed using a conventional fluorescence instrument, which makes this method easy to accomplish. Therefore, this rapid and effective method has the potential to provide rapid screening platforms for individuals with a high EBV load.

Algorithms for the Testing of Tissue Donors for Human Immunodeficiency Virus, Hepatitis B Virus, and Hepatitis C Virus

Background

Although transmission of pathogenic viruses through human tissue grafts is rare, it is still one of the most serious dreaded risks of transplantation. Therefore, in addition to the detailed medical and social history, a comprehensive serologic and molecular screening of the tissue donors for relevant viral markers for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) is necessary. In the case of reactive results in particular, clear decisions regarding follow-up testing and the criteria for tissue release must be made.

Methods

Based on the clinical relevance of the specific virus markers, the sensitivity of the serological and molecular biological methods used and the application of inactivation methods, algorithms for tissue release are suggested.

Results

Compliance with the preanalytical requirements and assessment of a possible hemodilution are mandatory requirements before testing the blood samples. While HIV testing follows defined algorithms, the procedures for HBV and HCV diagnostics are under discussion. Screening and decisions for HBV are often not as simple, e.g., due to cases of occult HBV infection, false-positive anti-HBc results, or early window period positive HBV NAT results. In the case of HCV diagnostics, modern therapies with direct-acting antivirals, which are often associated with successful treatment of the infection, should be included in the decision.

Conclusion

In HBV and HCV testing, a high-sensitivity virus genome test should play a central role in diagnostics, especially in the case of equivocal serology, and it should be the basis for the decision to release the tissue. The proposed test algorithms and decisions are also based on current European recommendations and standards for safety and quality assurance in tissue and cell banking.

Comparison of Total Immunoglobulin G in Ante- and Postmortem Blood Samples from Tissue Donors

Background

A serology testing for infectious diseases (HIV, hepatitis B and C, syphilis) is mandatory in tissue donors. In many donors postmortem blood is the only sample available. Even though serological tests and nucleic acid amplification tests (NAT) used are validated for postmortem blood, a characterization of those blood samples is not yet established. We therefore investigated the total immunoglobulin G (IgG) content in postmortem blood of tissue donors and compared it to a corresponding antemortem blood sample.

Methods

Ante- and postmortem blood samples were obtained from 100 consecutive tissue donors. The total IgG of all samples was measured using an immune-turbidometric test on the AU 480 Chemistry Analyzer (Beckman Coulter).

Results

The mean total IgG concentration of antemortem blood samples from all 100 donors was 8.9 g/L ± 3.7 g/L (median 8.9 g/L, range 1.5 to 23.8 g/L). In 80 donors the IgG concentration in the antemortem blood sample was within the normal range with values ≥6 g/L (mean 10.0 g/L ± 3.3 g/L, median 9.3 g/L,). The total IgG concentration of the postmortem blood samples was lower with 7.2 g/L ± 3.2 g/L (median 6.7 g/L, range 0.6 to 18.2 g/L). The difference between the values of the antemortem and postmortem blood samples was 1.7 g/L ± 2.6 g/L (16.3%) (median 1.6 g/L, range -7.7 to 10.1 g/L). In 36 donors this difference was less than 10%, in 23 it was between 10 and 25%, in 33 between 26 and 50%, and in 8 over 50%. In 57 donors the total IgG in the postmortem blood sample was within the normal range with ≥6 g/L, in 53 of them also the value of the antemortem blood sample was within the normal range. No correlation for total IgG was found regarding the donor characteristics (age, sex, disease) and the sample characteristics (hemolysis, postmortem time).

Conclusion

Total IgG values in antemortem samples were below the lower limit of 6 g/L in 20% of the cases. Total IgG was significantly lower in the postmortem samples compared to the antemortem samples, while 57% were still above the lower limit. No correlation with the postmortem time could be found. This lowered IgG levels should be payed attention to when using postmortem blood for infectious serology testing. Additional NAT testing should be considered.

Effect of different human tissue processing techniques on SARS-CoV-2 inactivation-review

The safety of the tissue transplant recipient is a top priority for tissue banks, and the emergence of the new coronavirus SARS-CoV-2 has raised significant concerns about the risks of releasing tissue for clinical use. In the present study, we conducted a literature review about the potential infectivity of SARS-CoV-2 in different biological tissues and the influence of various tissue processing and sterilization procedures on viral inactivation. The search revealed that SARS-CoV-2 binds to the human angiotensin-converting enzyme receptor to penetrate human cells. These receptors are present in skin cells, musculoskeletal tissue, amniotic membranes, cardiovascular tissue and ocular tissues, including the cornea. In general, we found that coronaviruses are stable at low temperatures, and inactivated upon exposure to extreme heat and pH. Notably, gamma irradiation, which has already been employed to inactivate SARS and MERS, could be useful for sterilizing skin, amnion and musculoskeletal tissues against SARS-CoV-2. We conclude that due to the limited information about the effects of physical and chemical tissue processing methods on viral neutralization, rigorous donor screening is still essential for tissue transplant recipient safety.

Use of HCV-Positive Livers in HCV-Negative Recipients

INTRODUCTION

There are only limited data on the survival outcomes after transplanting HCV RNA-positive liver into HCV RNA-negative recipients. The objective of our study was to determine whether there were graft and patient survival differences when HCV-negative patients received HCV RNA (nucleic acid amplification testing [NAT] positive)-positive liver grafts.

METHODS

We queried the United Network for Organ Sharing data sets from January 2014 to December 2018, and recipients (N = 24,724) were stratified into 6 groups based on the status of HCV antibody and RNA of recipients and donors. The Cox proportional hazard regression was used to estimate the relationship between groups and 1-year post-LT graft or patient survival.

RESULTS

During the study period, 1,358 recipients received NAT-positive liver grafts. Two hundred ten of the recipients were HCV negative. During the same period, 707 HCV antibody-positive but NAT-negative grafts were transplanted into 516 HCV-positive and 191 HCV-negative recipients. There were no differences in survival in HCV-positive recipients whether they received NAT-positive grafts (n = 1,148) or HCV antibody-negative/NAT-negative grafts (n = 6,321). Recipients of grafts from HCV antibody-positive/NAT-negative donors had similar survival whether recipients were HCV-negative patients (n = 191) or HCV-positive patients (n = 516), and their survival probabilities were similar to those of HCV-negative recipients (n = 6,321) receiving grafts from HCV antibody-negative/NAT-negative donors. Patient survival was lower (P = 0.049) when HCV-negative recipients (n = 210) received NAT-positive grafts compared with HCV-positive patients (n = 1,148) receiving NAT-positive grafts; however, when adjusted for recipient and donor characteristics, the difference was not significant.

DISCUSSION

HCV-negative recipients receiving HCV-positive liver grafts (NAT positive) have excellent 1-year survival outcomes.

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.

Detection and quantification of human immunodeficiency virus and hepatitis C virus in cadaveric tissue donors using different molecular tests

BACKGROUND

Tissues from cadaveric donors are used in several clinical circumstances, and the transmission of infectious diseases has been reported. Cadaveric donor (CD) blood sample analysis is challenging due to its poor quality. However, studies have demonstrated the usefulness of molecular based methods, and the lack of studies using available commercial molecular tests was reported.

OBJECTIVE

The aim of this study was to evaluate the performance, specificity, sensitivity, and accuracy of different commercial molecular tests for HIV and HCV detection and quantification in CD through spiked samples.

STUDY DESIGN

20 CD and 20 blood donor samples were tested using 1,000 copies/mL and 1,000 IU/mL of lyophilized standards of HIV and HCV, respectively. Samples were analyzed by different molecular kits: XPERT HCV Viral Load and HIV-1 (Cepheid), COBAS® TaqMan® HIV-1 and COBAS® TaqMan® HCV Test, v2.0 (Roche), and artus® HI Virus-1 QS-RGQ and artus® HCV RG RT-PCR Kit (Qiagen).

RESULTS

HIV and HCV in CD were detected by RT-PCR-based quantitative kits. The tests performed by the Cepheid and the Roche kits showed the most accurate, sensitive and specific results, however, a wide variability between the assays and kits was observed. The Qiagen kits did not demonstrate satisfactory results.

CONCLUSIONS

CD evaluation showed great variability. The Cepheid and Roche kits were more sensitive for detecting HIV on CD and Cepheid was the most efficient kit for HCV quantification in CD. The Roche and Cepheid kits can be used to screen tissue donors for HIV and HCV.

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.

Irradiation sterilization used for allogenetic tendon: a literature review of current concept

Tendon injury is a very common type of sports trauma, and its incidence has increased over the past decades. Surgical reconstruction with tendon allograft has been increasingly used to restore the motor function and stability of the injured site. However, the risk of disease transmission caused by allogeneic tendon transplantation has been a major problem for tissue bank researchers and clinicians. In order to eliminate the risk of disease transmission, a process of terminal sterilization is necessary. Ionizing irradiation, including gamma irradiation and electron beam irradiation is the most commonly used method for the terminal sterilization, which has been widely proved to be able to effectively inactivate the contained pathogens. Nevertheless, some accompanying damage to the mechanical and histological properties of collagen fibers in tendons will be caused. Therefore, more and more studies have begun to pay attention to the protective effect of radiation protection agents, including the radical scavengers and cross-linking agents, in the irradiation sterilization of allogeneic tendons.

[Bone banks : The state-of-the-art]

Bone banks are responsible for the collection, production, testing, packaging, storage and delivery of osseous grafts. In compliance with legal and quality requirements, it is their main task to ensure the biological properties and the microbiological safety of the transplants as well. German legal requirements for bone banking are explained and current standards with respect to donor selection, laboratory tests and tissue processing, as well as labeling are discussed. Production and preparation procedures should include a validated microbiological inactivation method that largely preserves the biological properties of the tissue.

Detection of hepatitis B virus in bone allografts from donors with occult hepatitis B infection

The implementation of nucleic acid testing in donor screening has improved the safety of tissue allografts. Although infectious disease transmission can be considered a rare event, the detection of occult hepatitis B infection remains challenging. The studies concerning this risk are mainly based on testing blood specimens. This work shows the correlation between results of samples obtained from donor blood and the corresponding tissue washing solution. Hepatitis B virus deoxyribonucleic acid was detected both in bone allografts from donors with serological profiles associated to active hepatitis B infection and occult hepatitis B infection. These results suggest that hepatitis B virus seems to concentrate in bone marrow even when a low viral load is present in peripheral blood. Even detection at molecular level is not enough to avoid the risk of hepatitis B virus transmission and a multiparametrical evaluation is required in tissue donor screening. The role of clinicians in recognition and reporting of allograft-associated infections is a major concern for the acquisition of experience to be applied in risk control of disease transmission.

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.

Deceased tissue donor serology and molecular testing for HIV, hepatitis B and hepatitis C viruses: a lack of cadaveric validated tests

Vital to patient safety is the accurate assessment and minimization of risk for human immunodeficiency virus (HIV), Hepatitis C (HCV), and Hepatitis B (HBV) virus transmission by deceased donor organ and tissue transplantation. The pathogens are tested by serological kits based on enzyme-linked immunosorbent assay (ELISA), chemiluminescence (CLIA) and eletrochemiluminescence (ECLIA) immunoassays. Organ transplantation is a highly successful life-saving treatment in Brazil, but the Brazilian Health Surveillance Agency currently mandates that all deceased organ donors are screened for HIV, HCV and HBV following living donor policies. In this review, six ELISA (Wama^®, Bio-Rad^®, Biomerieux^®, DiaSorin^®, Acon Biotech^® and Biokit^®), three CLIA (Abbott^®, Siemens^®, Diasorin^®) and one ECLIA (Roche^®) were utilized for evaluating the effectiveness of those serological tests for deceased donors in Brazil according to manufacturer's guidelines. NAT for HIV, HCV and HBV can assist with detection of pre-seroconversion for those infections, and only Cobas^® TaqScreen MPX^® test, the Tigris System^® Procleix Ultrio Assay^® and the Bio-Manguinhos^® HIV/HCV/HBV NAT are commercially available. Between all the tests, only the manufacturer Abbott^® and Cobas^® TaqScreen MPX^® test are currently validated for cadaver samples.

Implementation of a novel living-donor kidney transplant preoperative checklist within the electronic medical record: a pilot study

BACKGROUND

Checklist utilization in surgery has contributed to improved patient safety and reduced numbers of preventable complications. A living-donor kidney transplant (LDKT) preoperative checklist embedded within electronic medical record (EMR) was developed to enhance patient safety and prevent "never" events including: unexpected donor-recipient blood (ABO) incompatibility, positive (XM) cross match, infectious disease transmission, or procurement of an anatomically inappropriate allograft. Review of the initial 2 years of checklist utilization was performed.

FINDINGS

This safety instrument operates by facilitating critical review and referencing of source documentation to confirm ABO, XM, infectious risk, and organ anatomy compatibility. It was met with high compliance rates and no "never events" have occurred following its inception. The checklist is readily available in the EMR and is accessible by all members of the LDKT recipient healthcare team.

CONCLUSIONS

Checklist utilization was associated with zero LDKT "never event" occurrences. Surgeons felt the checklist was easy to use.

Development of a Multiplex Real-Time PCR Assay for the Detection of Treponema pallidum, HCV, HIV-1, and HBV

Treponema pallidum, hepatitis C virus (HCV), human immunodeficiency virus (HIV)-1, and hepatitis B virus (HBV) are major causes of sexually transmitted diseases passed through blood contact. The development of a sensitive and efficient method for detection is critical for early diagnosis and for large-scale screening of blood specimens in China. This study aims to establish an assay to detect these pathogens in clinical serum specimens. We established a TaqMan-locked nucleic acid (LNA) real-time polymerase chain reaction (PCR) assay for rapid, sensitive, specific, quantitative, and simultaneous detection and identification. The copy numbers of standards of these 4 pathogens were quantified. Standard curves were generated by determining the mean cycle threshold values versus 10-fold serial dilutions of standards over a range of 10(6) to 10(1) copies/μL, with the lowest detection limit of the assay being 10(1) copies/μL. The assay was applied to 328 clinical specimens and compared with enzyme-linked immunosorbent assay (ELISA) and commercial nucleic acid testing (NAT) methods. The assay identified 39 T. pallidum-, 96 HCV-, 13 HIV-1-, 123 HBV-, 5 HBV/HCV-, 1 T. pallidum/HBV-, 1 HIV-1/HCV-, and 1 HIV-1/T. pallidum-positive specimens. The high sensitivity of the assay confers strong potential for its use as a highly reliable, cost-effective, and useful molecular diagnostic tool for large-scale screening of clinical specimens. This assay will assist in the study of the pathogenesis and epidemiology of sexually transmitted blood diseases.

Global maxillary ridge augmentation with frozen radiation-sterilised bone blocks followed by implant placement: a case report

Due to atrophy of the tissue within the alveolar ridge, implantation must sometimes be preceded by bone regeneration. The use of allogeneic material allows the surgeon to prepare grafts of any shape and amount; therefore it is a good alternative to autograft reconstruction in patients with extensive atrophy of the alveolar ridge. The patient with maxillary anodontia showed insufficient width of the ridge along its entire length, which prevented implantation. Therefore, alveolar ridge reconstruction was planned. Four frozen, radiation-sterilised bone blocks processed in the Tissue Bank in Warsaw were used for reconstruction of the alveolar ridge. The blocks were grafted to the area of molars, premolars and lateral incisors bilaterally. Three months after surgery a normal union of transplants with the recipient site was achieved. Six implants were embedded and following the 6-month integration period a permanent prosthetic restoration was successfully performed. During a 38-month follow-up none of the implants were lost and the aesthetic or functional condition of the prosthetic restoration did not deteriorate. Frozen allogeneic radiation-sterilised bone blocks constitute good, efficient and safe material used in reconstruction of the alveolar ridge in extensive bone atrophy. This is only one of possible grafting materials for reconstruction of extremely atrophic alveolar ridge.

Characterization and risk of blood-borne virus transmission in organ transplantation: what are the priorities?

ABSTRACT 

Blood-borne virus transmission through organ transplantation, although rare, has been associated with severe complications in recipients. There are few data available to ascertain the risk of infection in organ transplantation for known and emerging pathogens, as most information comes from events of transmission, which are rare and not always well characterized. The balance between quality of life through organ transplantation and the risks of donor-derived infection can be improved through advances in donor screening, enhanced monitoring and a multidisciplinary approach to improving donor assessment and recipient biosurveillance. The involvement of investigators with clinical, laboratory, surveillance and policy expertise is critical to bridge research knowledge and clinical practice.

Hepatitis B transmission by cell and tissue allografts: How safe is safe enough?

More than 2 million human tissue transplants (bone, tendon, cartilage, skin, cornea, amniotic membrane, stem cells, heart valve, blood vessel, etc.), are performed worldwide every year. Cells and tissues are shared between countries which have different regulations and laboratory equipment and represent a risk of hepatitis B virus (HBV) transmission that has become a global safety concern. While the risk of transfusion-transmitted HBV infection from blood donations has been estimated, the rate of HBV transmission from donors to recipients of allografts is unknown and varies between different tissues. There are various important ways of reducing the transmission risk, but donor screening and donor testing are still the main factors for preventing HBV transmission. HBV detection is included in the routine screening tests for cell and tissue donors. The standard test for preventing transplant-transmitted hepatitis B is the hepatitis B surface antigen. The implementation of methods involving nucleic acid amplification and the new generation of reactives to detect viral antibodies or antigens with an immunoassay, has increased the sensitivity and the specificity of the screening tests. The objective of our research was to review the literature and critically analyse the different steps for avoiding HBV transmission in cell and tissue donors, focusing on the screening tests performed.

The reliability of HBV core antibody in serological screening for hepatitis B virus

INTRODUCTION

Accurate diagnosis of hepatitis B virus (HBV) infection is essential for infection control, treatment and screening of potential blood, organ and tissue donors. We assessed the sensitivity of the HBsAg and HBcAb as screening assays alone and in combination for detecting HBV infection in a series of Australian patients. The performance of the Architect (Abbott Diagnostics, Germany) and the Elecsys (Roche Diagnostics, Germany) platforms were assessed for detection of HBcAb.

METHODS

There were 2778 blood samples assessed using the COBAS Ampliprep/TaqMan test for HBV DNA, of which 331 sera had concurrent HBV serology testing. This allowed determination of the correlation between HBV DNA and different serological markers. Of the 331 sera, 260 had sufficient residual volume to be retested for HBcAb using both Elecsys and the Architect assays.

RESULTS

Of the 331 patients, one (0.3%) was negative by the Architect Anti-HBc II assay, in the presence of HBV DNA and positive HBsAg, consistent with recent infection. Positive HBcAb in the absence of HBV DNA was found in 67 of 331 (20.2%) patients. Of these, 18 of 67 had isolated HBcAb with negative results on all other tests, with 12 of 18 (3.6%) demonstrating low HBcAb signals on chemiluminscent microparticle assay. No cases of detectable HBV DNA in the presence of negative serology were found. When the HBcAb was used as a marker for past exposure or chronic HBV infection, the Architect Anti-HBc II assay demonstrated sensitivity and specificity of 98% and 79.9%, respectively, compared to 90% and 78.9%, respectively, for the Elecsys Anti-HBc assay. The combination of the Architect Anti-HBc II and HBsAg assays, as per conventional solid organ donor and recipient screening protocols, had 90% specificity and 100% sensitivity for determining HBV infection.

CONCLUSION

This study shows that the use of combined HBsAg and HBcAb is sensitive and reliable for screening and predicting HBV nucleic acid test (NAT) positivity, whereas HBcAb alone missed an acute infection in this study population. There were no significant differences detectable between the Architect and the Elecsys HBcAb assays (p=0.001), suggesting laboratories should assess individual assays in the local population before use as screening tests.

Nucleic acid testing and tissue safety: an eye bank's five-year review of HIV and hepatitis testing for donor corneas

PURPOSE

Tissue safety and added testing is a frequent topic of discussion among those who must evaluate donor suitability and assure appropriate testing. Therefore, the purpose of this report was to examine the data of one eye bank (accredited by Eye Bank Association of America) for the presence or absence of reactive serology in 3592 donors over a 5-year period, from 2005 to 2010.

METHODS

The number of specific analytes, human immunodeficiency virus (HIV), hepatitis B virus, or hepatitis C virus, that were reactive and the number of multireactive serologies are presented along with reports related to the identification of nucleic acid testing (NAT), NAT-reactive donors in correlation with other antigen or antibody markers. Antigen or antibody markers are enzyme-linked immunosorbent assay immunoassay kit determinations. NATs are used to measure the presence of RNA or DNA virus.

RESULTS

The 249 donors with reactive serologies serve to confirm the importance of serologic testing in history-negative potential donors. Furthermore, the findings of 2 HIV NAT-only reactive individuals is significant because it may indicate an early unrecognized exposure and "window period" infectivity not recognized by antibody testing alone. These results support the appropriate inclusion of this added test to guarantee tissue safety.

CONCLUSIONS

The finding of 2 potential donors without identified risk factors but with reactive HIV NAT suggests the need for comprehensive serologic testing in conjunction with medical social history screening. Considered together, screening and testing offer the best allograft tissue safety currently available.

Molecular HIV screening

Nuclear acid testing is more and more used for the diagnosis of infectious diseases. This paper focuses on the use of molecular tools for HIV screening. The term 'screening' will be used under the meaning of first-line HIV molecular techniques performed on a routine basis, which excludes HIV molecular tests designed to confirm or infirm a newly discovered HIV-seropositive patient or other molecular tests performed for the follow-up of HIV-infected patients. The following items are developed successively: i) presentation of the variety of molecular tools used for molecular HIV screening, ii) use of HIV molecular tools for the screening of blood products, iii) use of HIV molecular tools for the screening of organs and tissue from human origin, iv) use of HIV molecular tools in medically assisted procreation and v) use of HIV molecular tools in neonates from HIV-infected mothers.

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.

Effect of gamma irradiation on mechanical properties of human cortical bone: influence of different processing methods

The secondary sterilisation by irradiation reduces the risk of infectious disease transmission with tissue allografts. Achieving sterility of bone tissue grafts compromises its biomechanical properties. There are several factors, including dose and temperature of irradiation, as well as processing conditions, that may influence mechanical properties of a bone graft. The purpose of this study was to evaluate the effect of gamma irradiation with doses of 25 or 35 kGy, performed on dry ice or at ambient temperature, on mechanical properties of non-defatted or defatted compact bone grafts. Left and right femurs from six male cadaveric donors aged from 46 to 54 years, were transversely cut into slices of 10 mm height, parallel to the longitudinal axis of the bone. Compact bone rings were assigned to the eight experimental groups according to the different processing method (defatted or non-defatted), as well as gamma irradiation dose (25 or 35 kGy) and temperature conditions of irradiation (ambient temperature or dry ice). Axial compression testing was performed with a material testing machine. Results obtained for elastic and plastic regions of stress-strain curves examined by univariate analysis are described. Based on multivariate analysis it was found that defatting of bone rings had no significant effect on any mechanical parameter studied, whereas irradiation with both doses decreased significantly the ultimate strain and its derivative toughness. The elastic limit and resilience were significantly increased by irradiation with the dose 25 kGy, but not 35 kGy, when the time of irradiation was longer. Additionally, irradiation at ambient temperature decreased maximum load, elastic limit, resilience, and ultimate stress. As strain in the elastic region was not affected, decreased elastic limit resulted in lower resilience. The opposite phenomenon was observed in the plastic region, where in spite of the lower ultimate stress, the toughness was increased due to the increase in the ultimate strain. The results of our study suggest that there may be an association between mechanical properties of bone tissue grafts and the damage process of collagen structure during gamma irradiation. This collagen damage in cortical bone allografts containing water does not depends on the temperature of irradiation or defatting during processing if dose of gamma irradiation does not exceed 35 kGy.

Organ donor screening using parallel nucleic acid testing allows assessment of transmission risk and assay results in real time

Expansion of the donor pool may lead to utilization of donors with risk factors for viral infections. Donor laboratory screening relies on serological and nucleic acid testing (NAT). The increased sensitivity of NAT in low prevalence populations may result in false-positive results (FPR) and may cause unnecessary discard of organs.We developed a screening algorithm to deal, in real time, with potential FPR. Three NAT assays: COBAS AmpliScreen assay (CAS), AmpliPrep Total Nucleic Acid Isolation/CAS, and AmpliPrep/TaqMan assays, were validated and used in parallel for prospective screening of increased-risk donors (IRD), and the probability of FPR was calculated. The lower limit of detection of this algorithm was 9.79, 21.02, and 4.31 IU/mL for human immunodeficiency virus-1, hepatitis C virus, and hepatitis B virus, respectively, with an average turn-around-time of 7.67 h from sample receipt to result reporting. The probability that a donor is potentially infectious with two NAT concordant results was >90%. NAT screening of 35 IRD within 18 months resulted in transplantation of 102 additional organs that without screening would either not be used or used with restrictions in Australia. Using a parallel testing algorithm, real-time confirmation of seropositive donors allows use of organs from IRD and safer expansion of the donor pool.

Transplant-associated and blood transfusion-associated tropical and parasitic infections

Blood transfusion and transplantation may represent efficient mechanisms of spreading infectious agents to naive populations. In the developed countries, as a consequence of globalization, several factors such as international commerce, tourism, and immigration have acted as important features for the emergence or reemergence of infectious diseases previously referred to as tropical. This article reviews the relevant bacterial, protozoan and viral infections that are more frequently associated with blood transfusion and/or solid organ or marrow transplantation and may affect susceptible populations worldwide.

Inactivation Effect of Standard and Fractionated Electron Beam Irradiation on Enveloped and Non-Enveloped Viruses in a Tendon Transplant Model

BACKGROUND: For increasing allograft tendon safety in reconstructive surgery, an effective sterilization method achieving sterility assurance including viruses without impairing the grafts properties is needed. Fractionated Electron Beam (Ebeam) has shown promising in vitro results. The proof of sufficient virus inactivation is a central part of the process validation. METHODS: The Ebeam irradiation of the investigated viruses was performed in an optimized manner (oxygen content < 0.1%, -78 °C). Using principles of a tendon model the virus inactivation kinetics for HIV-2, HAV, pseudorabies virus (PRV) and porcine parvovirus (PPV) were calculated as TCID(50)/ml and D(10) value (kGy) for the fractionated (10 × 3.4 kGy) and the standard (1 × 34 kGy) Ebeam irradiation. RESULTS: All viruses showed comparable D(10) values for both Ebeam treatments. For sufficient virus titer reduction of 4 log(10) TCID(50)/ml, a dose of 34 kGy of the fractionated Ebeam irradiation was necessary in case of HIV-2, which was the most resistant virus investigated in this study. CONCLUSION: The fractionated and the standard Ebeam irradiation procedure revealed comparable and sufficient virus inactivation capacities. In combination with the known good biomechanical properties of fractionated Ebeam irradiated tendons, this method could be a safe and effective option for the terminal sterilization of soft tissue allografts.

Adverse reactions and events related to musculoskeletal allografts: reviewed by the World Health Organisation Project NOTIFY

PURPOSE

The use of bone and connective tissue allografts has grown rapidly and surpassed the use of autografts in many countries. Being of human origin, bone and tendon allografts carry the risk of disease transmission and complications have been reported. As part of the Project NOTIFY led by the World Health Organisation, an effort to improve recognition, reporting, tracking and investigation of adverse outcomes of allografts was initiated, achieving a comprehensive review of associated disease transmission and failures. Those involving the use of musculoskeletal allografts are reported here. A major objective is to involve orthopaedic surgeons in the improvement of the safe use of the musculoskeletal allografts.

METHODS

We reviewed the medical literature, requested reports from surgeons in selected professional organisations and informally surveyed tissue bank organisations and selected tissue bank professionals to discover reported and unreported cases of adverse outcomes. We analysed each case to decide the likelihood that the complication was truly allograft related.

RESULTS

The efficiency of the procedures involved in bone banking and bone and tendon allograft has improved significantly during the last three decades. The evolution of the incidence of reported adverse reactions and events reflects positively on the safety of transplanted tissues. Cases of bacterial and viral transmission by bone and tendon allografts occurred mainly with those that contained viable cells, were not processed to remove cells, or were not disinfected or sterilised. We documented cases of transmission of human immunodeficiency virus (HIV), hepatitis C virus (HCV), human T-lymphotropic virus (HTLV), unspecified hepatitis, tuberculosis and other bacteria. Reporting of these adverse outcomes has led to corrective actions and has significantly improved the safety of allograft use. However, it is probable that not all cases have been reported and investigated.

CONCLUSIONS

Considering the high quality standards achieved in many countries, the best approach for further improvement in the safety of allografts is through a systematic reporting of all serious adverse reactions and events in the context of a global biovigilance programme.

Donor-related issues in hand transplantation

The policies and procedures for solid-organ donation, under the auspices of the Organ Procurement and Transplantation Network, currently cannot be applied to hand donation, because a hand allograft is considered a tissue in the United States and is under the jurisdiction of the Food and Drug Administration. Hand transplant centers have developed their own protocols. This article discusses the unique elements of such protocols, including training and education, the consent process, the necessary recipient and donor data, donor management, and operating room procedures. Candidate listing, allocation, and oversight of hand donation in the future are also discussed.

Temporal bone bank: complying with European Union directives on human tissue and cells

BACKGROUND

Availability of allograft tympano-ossicular systems (ATOS) provides unique reconstructive capabilities, allowing more radical removal of middle ear pathology. To provide ATOS, the University of Antwerp Temporal Bone Bank (UATB) was established in 1988. ATOS use was stopped in many countries because of safety issues concerning human tissue transplantation. Our objective was to maintain an ATOS tissue bank complying with European Union (EU) directives on human tissues and cells.

METHODS

The guidelines of the Belgian Superior Health Council, including EU directive requirements, were rigorously applied to UATB infrastructure, workflow protocols and activity. Workflow protocols were updated and an internal audit was performed to check and improve consistency with established quality systems and changing legislations. The Belgian Federal Agency of Medicines and Health Products performed an inspection to examine compliance with national legislatives and EU directives on human tissues and cells. A sample of important procedures was meticulously examined in its workflow setting next to assessment of the infrastructure and personnel.

RESULTS

Results are reported on infrastructure, personnel, administrative workflow, procurement, preparation, processing, distribution, internal audit and inspection by the competent authority. Donors procured: 2006, 93 (45.1%); 2007, 64 (20.6%); 2008, 56 (13.1%); 2009, 79 (6.9%). The UATB was approved by the Minister of Health without critical or important shortcomings. The Ministry accords registration each time for 2 years.

CONCLUSIONS

An ATOS tissue bank complying with EU regulations on human allografts is feasible and critical to assure that the patient receives tissue, which is safe, individually checked and prepared in a suitable environment.