New developments in serologic screening of corneal donors for HIV-1 and hepatitis B virus infections

Seropositivity of blood samples of 31,355 cornea donors from a tertiary care network of eye banks

PURPOSE

To evaluate the seropositivity of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis from blood samples of cornea donors and assess correlation between seropositivity for HIV and syphilis.

METHODS

Retrospective analysis of blood samples of 31,355 cornea donors for HIV, HBV, HCV, and syphilis was performed. Postmortem blood samples were analyzed by a rapid screening test for anti-HIV envelope antibodies against HIV 1 and 2, HBV surface antigen, antibody to HCV and anti-cardiolipin antibodies for syphilis by rapid plasma reagin test.

RESULTS

The overall seropositivity rate was 4.28% (1343/31,355 donors). All positive donors were reactive for a single serological test. The seropositivity rate for HIV was 0.93% (95% CI 0.83-1.04%), for HBsAg was 1.56% (95% CI 1.43-1.7%), for HCV was 1.19% (95% CI 1.08-1.33%) and for syphilis was 0.59% (95% CI 0.52-0.69%). The trends in seropositivity rates showed a decline for three viral markers: HIV (2010, 1.17% to 2018, 0.72%, p = 0.02), HBsAg (2010, 1.98% to 2018, 1.05%, p = 0.0006) and HCV (2010, 1.32% to 2018, 0.43%, p < 0.0001). The seropositivity rates for syphilis showed a progressive increase when compared to baseline (2010, 0.14% to 2018, 1.14%, p < 0.0001). There was no relationship between seropositivity for HIV and syphilis (p = 0.18).

CONCLUSIONS

The overall seropositivity for HIV, HBV, HCV and syphilis was 4.28%. Seropositivity was highest for HBV. The study did not find correlation between seropositivity of HIV and syphilis.

Infectious Disease Transmission through Cell, Tissue, and Organ Transplantation: Reducing the Risk through Donor Selection

The incidence of cell transplant-transmitted infection is unknown and can only be inferred from prospective studies–that have not yet been performed and reported. The possibility of donor-to-recipient disease transmission through cell transplant therapy can be considered by reviewing the risk associated with other transplanted tissues and organs. Viral, bacterial, and fungal infections have been transmitted via transplantation of organs, tissue allografts such as bone, skin, cornea, and heart valves, and cells such as islets, hematopoietic stem cells, and semen. Several types of protozoan and worm parasites have been transferred via organ transplants. Bone allografts have transmitted hepatitis, tuberculosis, and human immunodeficiency virus (HIV-1). Corneas have transmitted rabies, Creutzfeldt-Jakob disease (CJD), hepatitis B (HBV), cytomegalovirus (CMV), herpes simplex virus (HSV), bacteria, and fungi. Heart valves have been implicated in transmitting tuberculosis and hepatitis B. HIV-1 and CMV seroconversion has been reported in patients receiving skin from seropositive donors. CJD has been transmitted by dura and pericardium transplants. Over the past several years, improvements in donor screening criteria, such as excluding potential donors with infection and those with behaviors risky for HIV-1 and hepatitis infection, and introduction of new donor blood tests have greatly reduced the risk of HIV-1 and hepatitis and may have nearly eliminated the risk of tuberculosis and CJD. Prior to use, many tissues are exposed to antibiotics, disinfectants, and sterilants, which further reduce or remove the risk of transmitted disease. Because organs, cells, and some tissue grafts cannot be subjected to sterilization steps, the risk of infectious disease transmission remains and thorough donor screening and testing is especially important.

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.

False-reactive test for hepatitis B surface antigen following administration of granulocyte-colony-stimulating factor

BACKGROUND AND OBJECTIVE

High-dose granulocyte transfusions are being administered to severely granulocytopenic patients. A single dose of G-CSF is given to donors for mobilization of granulocytes prior to donation.

MATERIALS AND METHODS

Infectious disease tests were performed on a donor before and after G-CSF was given.

RESULTS

Hepatitis B surface antigen (HBsAg) testing was transiently reactive following administration of G-CSF when examined using a test kit from one manufacturer, but not another. No other cause was found.

CONCLUSION

A false-reactive test for HBsAg using one manufacturer's test kit can occur following a single dose of G-CSF.

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.

Human immunodeficiency virus p24 antigen testing in cornea donors

PURPOSE

Testing for the p24 antigen of the human immunodeficiency virus (HIV) may detect early HIV infection in the seronegative window; however, falsely reactive results may occur in cadaver specimens. Although neither the Food and Drug Administration (FDA) nor the Eye Bank Association of America requires p24 testing of cornea donors, many tissue banks using other organs from cornea donors do perform this assay, and the FDA requires that eye banks reject corneal tissue if a reactive p24 assay is reported. We investigated the impact of p24 testing on eye banking and corneal transplantation.

METHODS

Two clinical cases and records from the Lions Eye Bank of Delaware Valley (LEBDV) were reviewed retrospectively.

RESULTS

Two corneas from the LEBDV were transplanted before the reporting of p24 reactivity by other tissue banks. In one case, because of the young age of the recipient, the surgeon elected to replace the cornea with new tissue hours after the original transplant, and later polymerase chain reaction (PCR) testing was negative. In the other case, there was not enough specimen to perform Western blot or PCR confirmatory testing. The patient was followed with periodic serologic testing for HIV and has remained seronegative. To avoid such problems in the future, the LEBDV initiated testing of all donors with p24 and other nonrequired screening tests. Over a 2-month period, 22 corneas (from 11 donors) were discarded because of these tests: 4 donors had reactive p24 tests, 6 were reactive for antibody to hepatitis B core antigen, and 1 had a reactive syphilis test.

CONCLUSIONS

Results from p24 assays by other tissue banks may cause difficult clinical situations when the results are received after transplantation of the tissue, but the use of the p24 assay in the screening of cornea donors may result in excessive waste of donor tissue. Further guidance is needed regarding the management of positive results from this and other nonrequired screening tests.

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

Human corneas are explanted for grafting as late as 72 h after death, for example, from medical examiner cases. Currently, infection of the donor with human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) is excluded in most cornea banks by serological testing of the cadaveric serum only. The reliability of this strategy was investigated by testing paired cadaveric and premortem sera of 33 potential donors. Results were discordant in 17 of 33 donors by at least one assay. Most frequently, HBsAg enzyme-linked immunosorbent assay (ELISA) yielded false-positive results with the cadaveric serum (16 of 33 serum pairs). Virus safety of the graft was affected in a single case, which was HCV antibody negative in the cadaveric serum, but positive in the premortem serum (confirmed by HCV-RIBA strip immunoassay). Forensic DNA profiling by polymerase chain reaction (PCR) of both serum samples confirmed that these were derived from the same individual. In conclusion, the results indicate that serological testing of cadaveric sera is not a reliable method for screening of potential cornea donors, and may not be sufficient for the virus safety of cornea grafts. Therefore, other screening strategies such as detection of viral nucleic acids by PCR should be evaluated.

Screening potential corneal donors for HIV-1 by polymerase chain reaction and a colorimetric microwell hybridization assay

PURPOSE

Current screening of potential corneal donors for human immunodeficiency virus type 1 (HIV-1) involves serologic detection of antibodies to the virus. However, this approach cannot detect infection during the seronegative window period of the disease. We therefore evaluated the polymerase chain reaction (PCR) assay for viral nucleic acid as a possible alternative to screening cadaveric blood for HIV-1.

METHODS

Blood specimens from cadavers diagnosed at autopsy with acquired immunodeficiency syndrome (AIDS) (n = 21), at high risk for HIV-1 infection (n = 47), and at no known risk (n = 350) were screened by PCR for HIV-1 proviral DNA and human leukocyte antigen (HLA)-DQ alpha sequences, and for HIV antibodies.

RESULTS

All AIDS group samples were seropositive; of these, 18 (86%) and 20 (95%) of 21 were positive for HIV by PCR of proteinase K- and Chelex-extracted pellets, respectively. The seropositive samples negative by PCR testing were shown to inhibit PCR amplification. Nine (19%) of 47 high-risk specimens were HIV-positive. The no-known-risk group yielded negative results. The overall sensitivities for PCR in the proteinase K- and Chelex-treated groups were 90% and 97%, respectively, compared with Western blot reactivity. If PCR-inhibitory samples and HLA-DQ alpha-negative samples had been eliminated, sensitivity would have been 100%. Specificity was 100% for each group.

CONCLUSIONS

Screening cadaveric blood by PCR may be feasible, but further refinement of the assay and blood specimen collection practices will be necessary for it to become routine. Future studies should focus on optimizing specimen procurement and preparation to reduce or eliminate specimens that inhibit PCR.

Testing for hepatitis B surface antigen in processing donor tissue for penetrating keratoplasty

PURPOSE

The Food and Drug Administration recently proposed a change in the screening of eye bank cornea donors for hepatitis B virus. Currently, most eye banks run confirmatory tests to reduce the frequency of false-positive hepatitis B virus surface antigen (HBsAg) tests. The Food and Drug Administration is considering a policy that would not allow confirmatory testing.

METHODS

A retrospective study of records of a regional eye bank was done to evaluate the results of screening and confirmatory tests for hepatitis B virus.

RESULTS

The positive predictive value of the HBsAg screening test (using hepatitis B virus antibody neutralization for comparison) was low, 12.5%. False-positive donors accounted for 11.4% of the tissue used for penetrating keratoplasty during 1994.

CONCLUSIONS

If confirmation tests were not allowed, considerable loss of suitable tissue would have occurred. We believe that the current standards allow safe and effective processing of donor ocular tissue.

Screening corneas for human immunodeficiency virus type 1 proviral DNA by polymerase chain reaction

PURPOSE

We evaluated the sensitivity of the polymerase chain reaction as a technique to directly screen potential donor corneas for human immunodeficiency virus type 1 (HIV-1) proviral DNA.

METHODS

DNA from the central 8.0-mm cornea, limbal cornea, aqueous humor, and retina from 22 eyes of 11 cadavers seropositive for HIV was extracted and amplified by polymerase chain reaction using primers specific for the gag and env regions of the HIV-1 genome. The identity of amplification products was confirmed by Southern blot hybridization.

RESULTS

Viral DNA was detected in four (18.2%) of 22 central corneas, one (4.5%) of 22 limbal corneas, one (6.3%) of 16 aqueous humor samples, and seven (31.8%) of 22 retinas. No correlation was noted between the presence of HIV-1 proviral DNA in samples from the central cornea and from the other tissues tested from the same eye.

CONCLUSIONS

Within the limits of our assay, processing and analysis of limbal cornea, aqueous humor, and retina by polymerase chain reaction may not reliably ascertain the presence of HIV-1 in the central, transplantable cornea.

Detection of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus in donor eyes using polymerase chain reaction

Detection of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) in donor eyes was performed. DNAs were extracted from the uvea, and they were amplified using the polymerase chain reaction (PCR). Amplified viral DNAs were detected with liquid hybridisation and chemiluminescent assay in which no radioactive materials were used. This method was shown to have a sensitivity limit of fewer than 10 copies of HIV, making it much more sensitive than the current techniques employed in eye banks. The method was applied to 120 donor eyes, including four from donors seropositive for HBV. The HBV gene was detected in one case in which the donor's blood had not been tested for HBV. HIV and HCV genes were not detected in any of the samples. The assay could be an effective screening test for the detection of these viruses in eye bank eyes.