Blood donor screening: how to decrease the risk of transfusion-transmitted hepatitis B virus?

QUESTIONS UNDER STUDY: The risk of transfusion-transmitted HBV remains significant in Switzerland, where routine screening for hepatitis B virus (HBV) in blood donations relies solely on serological hepatitis B surface antigen (HBsAg) testing. This study was designed to determine the prevalence of anti-hepatitis B core (anti-HBc) and HBV nucleic acid testing (NAT) positive donations in two different Swiss donor populations, to help in deciding whether supplemental testing may bring additional safety to blood products. METHODS: In a first population of donors, 18143 consecutive donations were screened initially for HBsAg, anti-HBc (with one EIA assay) and with HBV NAT in minipools of 24 donations. The screening repeatedly reactive anti-HBc donations were then "confirmed" with two supplemental anti-HBc assays, an anti-hepatitis B surface assay (anti-HBs) and with single donation HBV NAT. In a second population of donors, 4186 consecutive donations were screened initially with two different anti-HBc assays in addition to the mandatory HBsAg screening test. The screening repeatedly reactive donations with at least one anti-HBc assay were tested for anti-HBs. RESULTS: In the first subset of 18143 donations, 17593 (97.0%) were negative for HBsAg, anti-HBc and HBV NAT in minipools. 549 (3.0%) were HBsAg and HBV NAT negative, but repeatedly reactive for anti-HBc. Of these 549 donations, 287 could not be "confirmed" with two additional anti-HBc assays and were negative with an anti-HBs assay, as well as with single donation HBV NAT. Only 211 (1.2% of the total screened donations) were "confirmed" positive with at least one of two supplemental anti-HBc assays. One repeatedly reactive HBsAg donation, from a first-time donor, was confirmed positive for HBsAg and anti-HBc, as well as with single donation HBV NAT. In the second subset of 4186 donations, 4014 (95.9%) were screened negative for HBsAg and for anti-HBc, tested with two independent anti-HBc assays. 172 donations (4.1%) were HBsAg negative but repeatedly reactive with at least one of the two anti-HBc assays. Of these 172 samples, 86 were reactive with the first anti-HBc assay only, 13 were reactive with the second anti-HBc assay only and 73 (1.7% of the total screened donations) were "confirmed" positive with both anti-HBc assays. CONCLUSION: The prevalence of anti-HBc "confirmed" positive donations in the two Swiss blood donor populations studied was low (<2%) and we found only one HBV NAT positive (HBsAg positive) donation among more than 18000. Concerning blood product safety, an increase in the deferral rate of less than 2% of anti-HBc positive, potentially infectious donors, would in our opinion make routine anti-HBc testing of blood donations cost-effective. There is however still a need for more specific assays to avoid an unacceptably high deferral rate of "false" positive donors. In contrast, the introduction of HBV NAT in minipools gives minimal benefit due to the inadequate sensitivity of the assay. It remains to evaluate more extensively the value of individual donation NAT, alone or in addition to anti-HBc, as supplemental testing in the context of several Swiss blood donor populations.

Donor-to-host transmission of Candida glabrata to both recipients of corneal transplants from the same donor

PURPOSE: To report 2 cases of exogenous Candida glabrata endophthalmitis after penetrating keratoplasty in recipients of corneas from the same donor transplanted on the same day. METHODS: Case reports with ophthalmologic, electron microscopic, and microbiological findings including fungal strain analysis. RESULTS: Two patients developed fungal keratitis and endophthalmitis caused by the same C. glabrata strain within 1 day after penetrating keratoplasty of corneas from the same donor on the same day. Donor-to-host transmission was postulated when eye bank sterility checks were repeatedly negative. CONCLUSIONS: A short death-to-harvesting time, routine donor rim cultures, and respecting of a time interval before transplantation may provide an additional safety feature in dealing with corneal tissue from high-risk donors.

University of Wisconsin versus St. Thomas' Hospital solution for human donor heart preservation

Prolongation of the safe period of ischemia of the heart is an efficient way to overcome donor organ shortage, as demonstrated in renal and hepatic transplantation. We present the results of a prospective, randomized study comparing preservation with University of Wisconsin solution (UWS) versus St. Thomas' Hospital solution (STS) in clinical heart transplantation. A total of 39 patients were enrolled in the study (n = 20 for UWS and n = 19 for STS). Hemodynamic, electron microscopic, and biochemical evaluation did not reveal any significant differences in postoperative myocardial performance. Only the number of intraoperative defibrillations (0.82 for UWS versus 1.7 for STS) and the rhythm stability after reperfusion (13/20 UWS hearts versus 6/19 STS hearts in sinus rhythm) were significantly different. Heart preservation with UWS and STS appears to be of comparable efficacy at mean ischemic times of less than 4 hours.

FoxP3 positive T cells in graft biopsies from living donor kidney transplants after donor-specific transfusions

Donor-specific transfusions (DST) induce allograft tolerance in animals. Evidence is growing that FoxP3+ regulatory T cells are associated with tolerance in humans. Forty-four biopsies from 69 living donor kidney transplant recipients (LDT) after DST, 53 biopsies from 69 matched deceased donor transplant recipients (DDT), obtained for graft dysfunction, and 12 biopsies from LDT without DST were retrospectively analyzed. FoxP3 positivity was more frequent in LDT/DST than in DDT biopsies (67% vs. 44%, P=0.02). Considering only biopsies with acute rejection, FoxP3 positivity was observed in 92% (11/12) after LDT/DST, but only in 50% (6/12) after DDT (P=0.03). The number of FoxP3+ T cells per total infiltrating cells in rejection biopsies was higher (P<0.05) from LDT/DST (4.1%) than from DDT or LDT (2.6%) without DST (2.5%). Six-year graft survival was better in patients with LDT/DST than with DDT (87.5% vs. 79.7%, P=0.04). The present investigation demonstrates an association between DST and FoxP3+ T cells. The effect of DST on regulatory T cells deserves further analysis in transplantation.

Cellular senescence of white blood cells in very long-term survivors after allogeneic hematopoietic stem cell transplantation: the role of chronic graft-versus-host disease and female donor sex

In this single-center, cross-sectional study, we evaluated 44 very long-term survivors with a median follow-up of 17.5 years (range, 11-26 years) after hematopoietic stem cell transplantation. We assessed the telomere length difference in human leukocyte antigen-identical donor and recipient sibling pairs and searched for its relationship with clinical factors. The telomere length (in kb, mean +/- SD) was significantly shorter in all recipient blood cells compared with their donors' blood cells (P < .01): granulocytes (6.5 +/- 0.9 vs 7.1 +/- 0.9), naive/memory T cells (5.7 +/- 1.2 vs 6.6 +/- 1.2; 5.2 +/- 1.0 vs 5.7 +/- 0.9), B cells (7.1 +/- 1.1 vs 7.8 +/- 1.1), and natural killer/natural killer T cells (4.8 +/- 1.0 vs 5.6 +/- 1.3). Chronic graft-versus-host disease (P < .04) and a female donor (P < .04) were associated with a greater difference in telomere length between donor and recipient. Critically short telomeres have been described in degenerative diseases and secondary malignancies. If this hypothesis can be confirmed, identification of recipients at risk for cellular senescence could become part of monitoring long-term survivors after hematopoietic stem cell transplantation.

Synthesis of NO-donor bisphosphonates and their in-vitro action on bone resorption

A new class of bisphosphonates containing nitrooxy NO-donor functions has been developed. The products proved to display affinity for hydroxyapatite. Injection of (99m)Tc-labeled derivatives 11 and 18 into male rats showed a preferential accumulation of the compounds in bone as compared to blood and muscles. The products were found to inhibit the differentiation of pre-osteoclasts to functional osteoclasts induced by receptor activator of NF-kappaB ligand (RANKL), through a prevalent NO-dependent mechanism.

Enhancement of excess electron transfer efficiency in DNA containing a phenothiazine donor and multiple stable phenanthrenyl base pairs

EET grown ohm: Excess electron transfer (EET) was observed within a DNA duplex containing π-stacked phenothiazine as an electron donor, phenanthrenes as electron carriers and 5-bromouracil as an electron trap. Increasing the number of phenanthrenyl base pairs increased EET efficiency.

Effects of exogenous surfactant on the non-heart-beating donor lung graft in experimental lung transplantation - a stereological study.

The use of non-heart-beating donor (NHBD) lungs may help to overcome the shortage of lung grafts in clinical lung transplantation, but warm ischaemia and ischaemia/reperfusion injury (I/R injury) resulting in primary graft dysfunction represent a considerable threat. Thus, better strategies for optimized preservation of lung grafts are urgently needed. Surfactant dysfunction has been shown to contribute to I/R injury, and surfactant replacement therapy is effective in enhancing lung function and structural integrity in related rat models. In the present study we hypothesize that surfactant replacement therapy reduces oedema formation in a pig model of NHBD lung transplantation. Oedema formation was quantified with (SF) and without (non-SF) surfactant replacement therapy in interstitial and alveolar compartments by means of design-based stereology in NHBD lungs 7 h after cardiac arrest, reperfusion and transplantation. A sham-operated group served as control. In both NHBD groups, nearly all animals died within the first hours after transplantation due to right heart failure. Both SF and non-SF developed an interstitial oedema of similar degree, as shown by an increase in septal wall volume and arithmetic mean thickness as well as an increase in the volume of peribron-chovascular connective tissue. Regarding intra-alveolar oedema, no statistically significant difference could be found between SF and non-SF. In conclusion, surfactant replacement therapy cannot prevent poor outcome after prolonged warm ischaemia of 7 h in this model. While the beneficial effects of surfactant replacement therapy have been observed in several experimental and clinical studies related to heart-beating donor lungs and cold ischaemia, it is unlikely that surfactant replacement therapy will overcome the shortage of organs in the context of prolonged warm ischaemia, for example, 7 h. Moreover, our data demonstrate that right heart function and dysfunctions of the pulmonary vascular bed are limiting factors that need to be addressed in NHBD.

A comparative assessment of endothelium from pseudophakic and phakic donor corneas stored in organ culture

AIMS To evaluate the endothelial quality of corneas obtained from pseudophakic donors and to compare the data with matched phakic controls. METHODS Corneas from eyes with posterior chamber intraocular lenses (PCIOLs) and corneas from phakic eyes (controls) were stored for 1-2 weeks in organ culture and then examined after staining with Alizarin red S. The corneas were divided into two groups according to the duration of storage. Endothelial cell density, the percentage of hexagonal cells, and the coefficient of variation (CV) were determined. RESULTS There was no statistically significant difference between the 14 PCIOL corneas and the 13 controls stored in organ culture for 7 days for any of the three parameters studied. The mean cell density was 2155 (SD 529) cells/mm(2) in the PCIOL corneas and 2118 (453) cells/mm(2) in the controls (p=0.85). The mean percentage of hexagonal cells was 52% (8%) and 58% (7%), respectively (p=0.06). The mean CV was 0.32 (0.18) in the pseudophakic corneas and 0.39 (0.18) in the controls (p=0.33). Moreover, there was no significant difference between the PCIOL corneas and the controls stored for up to 2 weeks. CONCLUSIONS The corneal endothelium from eyes with PCIOLs appears to be similar to that of phakic eyes after 1-2 weeks in organ culture. This finding suggests that corneas from pseudophakic eyes should not routinely be disqualified for transplantation. The use of at least some pseudophakic corneas may substantially increase the potential donor pool.

Liver Remnant Regeneration in Donors After Living Donor Liver Transplantation: Long-Term Follow-Up Using CT and MR Imaging

Purpose: To assess liver remnant volume regeneration and maintenance, and complications in the long-time follow-up of donors after living donor liver transplantation using CT and MRI. Materials and Methods: 47 donors with a mean age of 33.5 years who donated liver tissue for transplantation and who were available for follow-up imaging were included in this retrospective study. Contrast-enhanced CT and MR studies were acquired for routine follow-up. Two observers evaluated pre- and postoperative images regarding anatomy and pathological findings. Volumes were manually measured on contrast-enhanced images in the portal venous phase, and potential postoperative complications were documented. Pre- and postoperative liver volumes were compared for evaluating liver remnant regeneration. Results: 47 preoperative and 89 follow-up studies covered a period of 22.4 months (range: 1 - 84). After right liver lobe (RLL) donation, the mean liver remnant volume was 522.0 ml (± 144.0; 36.1 %; n = 18), after left lateral section (LLS) donation 1,121.7 ml (± 212.8; 79.9 %; n = 24), and after left liver lobe (LLL) donation 1,181.5 ml (± 279.5; 72.0 %; n = 5). Twelve months after donation, the liver remnant volume were 87.3 % (RLL; ± 11.8; n = 11), 95.0 % (LS; ± 11.6; n = 18), and 80.1 % (LLL; ± 2.0; n = 2 LLL) of the preoperative total liver volume. Rapid initial regeneration and maintenance at 80 % of the preoperative liver volume were observed over the total follow-up period. Minor postoperative complications were found early in 4 patients. No severe or late complications or mortality occurred. Conclusion: Rapid regeneration of liver remnant volumes in all donors and volume maintenance over the long-term follow-up period of up to 84 months without severe or late complications are important observations for assessing the safety of LDLT donors. Key Points: Liver remnant volumes of LDLT donors rapidly regenerated after donation and volumes were maintained over the long-term follow-up period of up to 84 months without severe or late complications.

Genomic cloning and expression of three murine UDP-galactose: beta-N-acetylglucosamine beta1,3-galactosyltransferase genes.

Based on the detection of expressed sequence tags that are similar to known galactosyltransferase sequences, we have isolated three novel UDP-galactose:beta-N-acetylglucosamine beta1, 3-galactosyltransferase (beta3GalT) genes from a mouse genomic library. The three genes, named beta3GalT-I, -II, and -III, encode type II transmembrane proteins of 326, 422, and 331 amino acids, respectively. The three proteins constitute a distinct subfamily as they do not share any sequence identity with other eucaryotic galactosyltransferases. Also, the entire protein-coding region of the three beta3GalT genes was contained in a single exon, which contrasts with the genomic organization of the beta1,4- and alpha1, 3-galactosyltransferase genes. The three beta3GalT genes were mainly expressed in brain tissue. The expression of the full-length murine genes as recombinant baculoviruses in insect cells revealed that the beta3GalT enzymes share the same acceptor specificity for beta-linked GlcNAc, although they differ in their Km for this acceptor and the donor UDP-Gal. The identification of beta3GalT genes emphasizes the structural diversity present in the galactosyltransferase gene family.

A Compact Tetrathiafulvalene-Benzothiadiazole Dyad and Its Highly Symmetrical Charge-Transfer Salt: Ordered Donor π-Stacks Closely Bound to Their Acceptors

A compact and planar donor–acceptor molecule 1 comprising tetrathiafulvalene (TTF) and benzothiadiazole (BTD) units has been synthesised and experimentally characterised by structural, optical, and electrochemical methods. Solution-processed and thermally evaporated thin films of 1 have also been explored as active materials in organic field-effect transistors (OFETs). For these devices, hole field-effect mobilities of μFE=(1.3±0.5)×10−3 and (2.7±0.4)×10−3 cm2 V s−1 were determined for the solution-processed and thermally evaporated thin films, respectively. An intense intramolecular charge-transfer (ICT) transition at around 495 nm dominates the optical absorption spectrum of the neutral dyad, which also shows a weak emission from its ICT state. The iodine-induced oxidation of 1 leads to a partially oxidised crystalline charge-transfer (CT) salt {(1)2I3}, and eventually also to a fully oxidised compound {1I3}⋅1/2I2. Single crystals of the former CT compound, exhibiting a highly symmetrical crystal structure, reveal a fairly good room temperature electrical conductivity of the order of 2 S cm−1. The one-dimensional spin system bears compactly bonded BTD acceptors (spatial localisation of the LUMO) along its ridge.

Electronic tuning effects via π-linkers in tetrathiafulvalene-based dyes

Four new tetrathiafulvalene (TTF)-based dyes featured with a donor–bridge–acceptor (D–π–A) structure were synthesized and characterized. All of them undergo two reversible oxidations to form stable radical cation and dication species. The electronic interactions between the TTF donor and the cyanoacrylic acid acceptor through the different π-linkers have been demonstrated by the presence of a photo-induced intramolecular charge-transfer (ICT) absorption band in the visible region. A red shift of the ICT state can be finely tuned by the degree of aromaticity and extended conjugation of π-bridges. To some extent, the oxidation potentials of these dyes are affected by the nature of π-bridges. They have been applied in organic dye-sensitized solar cells, showing relatively low power conversion efficiencies of up to 0.87% due to substantial charge recombination losses.