PD06-03: Cost Effectiveness Analysis of BRCA1/2 Genetic Testing

Background: Family history of breast and/or ovarian cancer is associated with an increased risk to carry a BRCA1 or BRCA2 gene mutationmutations which significantly increase a woman's risk to develop breast and/or ovarian cancer. This study examines whether BRCA1/2 genetic testing (intervention) remains cost-effective compared to no genetic testing strategy (control) from the societal and private payer perspectives given updates in healthcare practice, policy and clinical specificity of testing in the last 10 years.

Data and method: We updated a previous published semi-Markov model (Holland et al., Value in Health, 2009. 12(2): p. 207) to include new information about associated costs and treatment strategies and test specificity. The target population is 35 year old asymptomatic US women with an elevated risk of BRCA1/2 genetic mutation. The estimates of probability (prevalence, risk, preference and mortality), cost, and utility are derived from published reports and BRCA1/2 test technical documentation. We conducted the basecase cost-utility analysis and a series of sensitivity analyses by varying pretest probability of BRCA1/2 mutation, clinical sensitivity of BRCA1/2 testing, initial utility after BC diagnosis and patient preference in the first year after mastectomy, cost of BRCA1/2 testing, and out-of-pocket costs.

Results: From the societal perspective, the “no test” strategy was estimated to cost $162K and resulted in 20.2 QALY gain over a patient's lifetime. The “test” strategy was estimated to cost $172K and result in 20.5 QALY gain, resulting in the incremental cost effectiveness ratio (ICER) of $30.6K/QALY. From a private payer perspective, the ICER was $36.8K/QALY. By conducting sensitivity analyses, we concluded that the model was robust to variation in the model parameters. Within the ranges of most variable estimates, the test strategy was more cost effective compared to the no-test strategy. The initial utility after BC diagnosis (basecase value 0.75) does not impact the choice of preferred strategy (testing is always preferred). Based on the probability of mutation for women with family history (basecase value 8.7%), testing is preferred if probability is greater than 3.1%, while no testing is preferred for values <3.1%. Only if cost of genetic testing is greater than $8,948 testing would it no longer be cost effective, which is however far beyond even the upper bound of cost estimate ($4,500). As long as the sensitivity of BRCA testing remains greater than 80% and initial utility after mastectomy <0.9, the testing is preferred over no testing.

Discussion: The strategy of BRCA1/2 testing of women at high risk for BRCA1/2 mutations and treatment of BRCA1/2 positive women is cost-effective compared to “no genetic testing” strategy. Cost of the actual test is not a barrier to its cost-effectiveness. Despite adding MRI to breast cancer surveillance in high risk population and increases in healthcare costs, BRCA1/2 testing remains cost-effective from both the societal and from a private payer perspectives for an unaffected population with BRCA1/2 prevalence of greater than 3%.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD06-03.

A shorter interval between irradiation of recipient testis and germ cell transplantation is detrimental to recovery of fertility in rams

The objective of the current study was to identify an optimal time period for donor cell transplantation after irradiation in sheep. The testes of recipient rams were treated with a single dose of 15 Gray (Gy) irradiation followed by germ cell transplantation either 3 or 6 weeks later. Transplantation of donor cells at 6 weeks after irradiation resulted in production of donor sperm by all five recipient rams compared with 4 of 11 rams transplanted at 3 weeks. Rams transplanted 3 weeks post-irradiation appeared to show reduced libido and fertility. Two rams produced sperm with low motility (< 20%) and two other rams were azoospermic. More than 1 year after cell transfer, there were heavy infiltrates of CD45-positive cells and more fibrous tissue in 9 of 14 recipient testes (seven rams) that received cells 3 weeks after irradiation. Taken together, these results suggest that the interval between irradiation of recipients and germ cell transplantation affects the success rate of the procedure, with a 6-week interval preferable. The elevated inflammatory/immune reaction may be responsible, at least in part, for the reduced fertility and low libido observed in the rams that received cells 3 weeks post-irradiation.

Patient and rheumatologist perspectives on glucocorticoids: an exercise to improve the implementation of the European League Against Rheumatism (EULAR) recommendations on the management of systemic glucocorticoid therapy in rheumatic diseases

OBJECTIVE

To explore perspectives among patients and rheumatologists on glucocorticoid (GC) therapy and European League Against Rheumatism (EULAR) recommendations on the management of systemic GC therapy in order to enhance implementation of the recommendations.

METHODS

Rheumatologists (from eight countries) and patients (from five countries) acquainted with GCs participated in separate meetings, during which positive and negative aspects of GC therapy were discussed and possible adverse events (AEs) were ranked for importance; in addition participants were asked to evaluate the published EULAR recommendations. The reports from these meetings and themes related to implementation of the recommendations were discussed during an international forum of the experts who had formulated the recommendations and patient participants.

RESULTS

In all, 140 patients (78% women; mean age 53 years; 61% patients with rheumatoid arthritis) and 110 rheumatologists (mean work experience 15 years) participated in the meetings. Osteoporosis, diabetes and cardiovascular diseases were ranked among the five most worrisome AEs by patients and rheumatologists. In both groups, there was agreement with most of the recommendations; the recommendations on GC information cards and GC use during pregnancy scored lowest. Ideas to improve implementation of the recommendations and a research agenda were generated.

CONCLUSION

The patient and rheumatologist views on GCs corresponded to a large extent, reflected by concerns in both groups about osteoporosis, diabetes and cardiovascular diseases. Specific problems with the EULAR recommendations were identified and addressed to improve their implementation. This exercise shows that patient and rheumatologist perspectives should be included early in the process of formulating recommendations.

The use and understanding of CA125 as a tumor marker for ovarian cancer: a questionnaire-based survey

The aim of this study was to assess the level of understanding of the role of the tumor marker CA125 in ovarian cancer among doctors of different grades specializing in obstetrics and gynecology (O&G), medicine, surgery, and primary care (general practitioners [GPs]). The study involves a questionnaire-based survey. Two hundred and fifty-nine questionnaires were distributed. An overall response rate of 47.1% was achieved. All grades of doctors and all major specialties were represented. There was a significant difference in the level of self-reported CA125 ordering between the medical specialties, O&G being the most frequent users and primary care the least (P< 0.001), and between the grade of doctors, senior house officers/preregistration house officers and GPs less than consultants and middle grade doctors (P< 0.001). Electronic literature was the first source of advice for the majority of respondents (38.5%). The knowledge of false-positive causes for a raised CA125 was low in medicine, surgery, and primary care specialties, as was the awareness of the sensitivity and specificity of CA125 in epithelial and nonepithelial ovarian cancers. The role of CA125 in ovarian cancer is poorly understood, especially among doctors working outside O&G. Guidelines should be developed to aid clinicians from all specialties in the most appropriate application of CA125 in their practice. Substantial cost savings could be made by the introduction of clear protocol-driven ordering in an attempt to reduce the number of inappropriate tests performed.

405. Isolation and preliminary characterisation of putative sheep embryonic stem cells

The establishment of true, fully characterised embryonic stem (ES) cells from livestock, (eg sheep) has yet to be reported. Such cells could make a significant impact on assisted reproductive technologies, vaccine delivery, and animal health and well being in the livestock industries. To date in sheep, there is a single report of putative ES cells which were maintained in an undifferentiated state for only 2 passages. Here we report the isolation and culture of pluripotent ES-like cells from in vivo derived, vitrified, sheep blastocysts. The inner cell mass of blastocysts were isolated by immunosurgery, cultured in Stem Cell Sciences' (SCS) novel inhibitor-based media, on a feeder layer of mouse embryonic fibroblasts (MEFs), resulting in putative ovine ES cells proliferating to at least passage 5. One cell line, BMCOV002, was established out of four thaw-recovered embryos. The colonies formed compact, near homogenous, small cell, multilayered, and well defined dome shaped masses that were morphologically similar to both mouse and human ES cell colonies. A peripheral halo of filamentous differentiated cells was detected in selected colonies from passage 3 to passage 5. The putative ovine ES-like cells were passaged by mechanical excision between days 6–7, and these colonies stained positive for alkaline phosphatase at both passage 3 and passage 5. Expression levels of genes encoding the pluripotent transcription factors OCT4, SOX2, REX1 and NANOG are shown using RT PCR in cells from passage 3. An important first step in studying the properties of ovine ES-like cells is the ability shown here to isolate and culture cells. Our attention now is focussed on maintaining these cells for some months in an undifferentiated state, and on being able to successfully cryopreserve and regenerate these cell lines.

Released momentum distribution of a Fermi gas in the BCS-BEC crossover

We develop a time-dependent mean-field theory to investigate the released momentum distribution and the released energy of an ultracold Fermi gas in the BCS-BEC crossover after the scattering length has been set to zero by a fast magnetic-field ramp. For a homogeneous gas we analyze the nonequilibrium dynamics of the system as a function of the interaction strength and of the ramp speed. For a trapped gas the theoretical predictions are compared with experimental results.

Differential glycosylation of polyclonal IgG, IgG-Fc and IgG-Fab isolated from the sera of patients with ANCA-associated systemic vasculitis

Post-translational modifications (PTMs) of proteins produced in vivo may be tissue, developmentally and/or disease specific. PTMs impact on the stability and function of proteins and offer a challenge to the commercial production of protein biotherapeutics. We have previously reported a marked deficit in galactosylation of oligosaccharides released from polyclonal IgG isolated from sera of patients with the anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitides; Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA). Whilst normal polyclonal IgG molecules are glycosylated within the IgG-Fc region, approximately 20% of molecules also bear oligosaccharides attached to the variable regions of the light or heavy chain IgG-Fab. It is of interest, therefore to compare profiles of oligosaccharides released from the IgG-Fc and IgG-Fab of normal IgG with that isolated from the sera of patients with WG or MPA. This study shows that whilst the oligosaccharides released from ANCA IgG-Fc are hypogalactosylated those released from IgG-Fab are galactosylated and sialylated. These results show that hypogalactosylation of IgG-Fc is not due to a defect in the glycosylation or processing machinery. It rather suggests a subtle change in IgG-Fc conformation that influences the addition of galactose. Remarkably, this influence is exerted on all plasma cells. Interestingly, a licensed monoclonal antibody therapeutic, produced in Sp2/0 cells, is also shown to be hypogalactosylated in its IgG-Fc but fully galactosylated in its IgG-Fab.

A hemispherical, high-solid-angle optical micro-cavity for cavity-QED studies

We report a novel hemispherical micro-cavity that is comprised of a planar integrated semiconductor distributed Bragg reflector (DBR) mirror, and an external, concave micro-mirror having a radius of curvature 50 microm. The integrated DBR mirror containing quantum dots (QD), is designed to locate the QDs at an antinode of the field in order to maximize the interaction between the QD and cavity. The concave micro-mirror, with high-reflectivity over a large solid-angle, creates a diffraction-limited (sub-micron) mode-waist at the planar mirror, leading to a large coupling constant between the cavity mode and QD. The half-monolithic design gives more spatial and spectral tuning abilities, relatively to fully monolithic structures. This unique micro-cavity design will potentially enable us to both reach the cavity quantum electrodynamics (QED) strong coupling regime and realize the deterministic generation of single photons on demand.

68 GENE EXPRESSION COMPARISONS BETWEEN BOVINE IN VIVO AND CLONED EMBRYOS PRODUCED BY THREE DIFFERENT METHODS

Developmental pathways in the mammalian embryo are profoundly influenced by the epigenetic interaction of the environment and the genome. Loss of epigenetic control has been implicated in aberrant gene expression and altered imprinting patterns with consequence to the physiology and viability of the conceptus. Bovine somatic cell nuclear transfer (SCNT) is contingent on in vitro culture, and both SCNT and culture conditions are known to induce changes in embryonic gene expression patterns. Using these experimental models, this study compared gene expression of Day 7 cloned blastocysts created from three different SCNT protocols using the same cell line, with Day 7 in vivo blastocysts to elucidate mechanisms responsible for variations in phenotypic outcomes. SCNT methods included: (1) traditional SCNT by subzonal injection (SI); (2) handmade cloning (HMC); and (3) modified serial nuclear transfer (SNT), developed within the group. Four imprinted genes (Grb10, Ndn, Nnat, and Ube3a), four chromatin remodeling genes (Cbx1, Cbx3, Smarca4, and Smarcb1) and two genes implicated in polycystic liver disease (Prkcsh and Sec63) were analyzed in single blastocysts from each treatment (n = 5). All blastocysts expressed Actin, Oct-4 and Ifn-tau. All genes were sequence verified. Several genes were expressed ubiquitously across all groups, including Ndn, Ube3a, Cbx1, Cbx3, and Smarcb1. Interestingly, Grb10 was not expressed in two HMCs and one SNT blastocyst. Nnat was weakly expressed in one in vivo blastocyst and in the majority of cloned blastocysts in all groups. Prkcsh and Sec63 were expressed in all but one HMC blastocyst. While gene expression patterns were mostly maintained following SCNT, the imprinted genes Nnat and Grb10 showed instances of differential or abnormal expression in SCNT embryos. The chromatin remodeling genes were maintained in all SCNT treatments. Prkcsh and Sec63 were both absent in one HMC blastocyst, with implications for liver dysfunction, a condition previously reported in abnormal cloned offspring. The variable mRNA expression following SCNT provides an insight into genetic and environmental factors controlling implantation, placentation, organ formation, and fetal growth.

Pressure coring, logging and subsampling with the HYACINTH system

The HYACINTH suite of equipment has been developed to investigate the pressure sensitive behaviour of sedimentary formations up to 250 bar (25 MPa). It does this by collecting pressure-preserved samples from boreholes that can be retrieved, subsampled and analysed in controlled conditions in the laboratory. This paper reviews the development of the system, how it originated from the need to better understand the nature and distribution of gas hydrates beneath the sea bed, and its achievements to date. While gas hydrates continue to be the major scientific and commercial impetus for using, and further developing, this pressure-sampling technology, other important scientific driving forces, including the growing interest in the deep biosphere beneath the sea floor, are playing an important role. We review the downhole tools, the transfer system and the suite of different pressure chambers that are required to make a complete working system. Non-destructive logging of cores contained in pressure chambers, using existing gamma- and X-ray techniques, is discussed, as are future logging techniques that will have sensors embedded within the pressure chambers. Subsamples can now be taken at full pressure and transferred into specialized chambers where intrusive measurements and experiments can be performed (e.g. inoculation chambers for microbiology). The versatile philosophy behind the integrated systems will enable future developments to be made by third parties who want to obtain subsamples at in situ pressure from the HYACINTH system. We conclude by reviewing some of the highlights of the HYACINTH operations on ODP Leg 204 where the downhole tools retrieved cores containing gas hydrates (up to 40% by volume) that were subsequently logged on board in the laboratory. These data have already contributed to the scientific understanding of the nature and distribution of gas hydrates beneath the seabed in one area on the Oregon Margin off the USA.

Momentum distribution of a Fermi gas of atoms in the BCS-BEC crossover

We observe dramatic changes in the atomic momentum distribution of a Fermi gas in the crossover region between the BCS theory superconductivity and Bose-Einstein condensation (BEC) of molecules. We study the shape of the momentum distribution and the kinetic energy as a function of interaction strength. The momentum distributions are compared to a mean-field crossover theory, and the kinetic energy is compared to theories for the two weakly interacting limits. This measurement provides a unique probe of pairing in a strongly interacting Fermi gas.

262. Towards derivation of primordial germ cells from murine embryonic stem cells

The process of primordial germ cell (PGC) specification begins at the earliest stages of murine embryogenesis. The mechanisms underlying this process are the strong instructive cues generated by the extra-embryonic ectoderm, which, via ligand-receptor signalling in the visceral endoderm, activate pathways in the proximal epiblast to induce the PGC phenotype. We have subjected murine embryonic stem (ES) cells to similar cues in order to drive PGC lineage specification in vitro. ES cells were differentiated as aggregates (embryoid bodies (EBs)), a process that is thought to recapitulate the early stages of embryogenesis by providing an environment conducive to the spontaneous emergence of multiple cell lineages. To date, we have shown that EBs can also support the spontaneous emergence of cells expressing PGC markers. Expression analysis was performed on EBs from 1 to 30 days in culture. PGC markers, including nanog, dazl, fragilis, stella and SSEA1, are expressed in undifferentiated ES cells, but rapidly become undetectable in EBs as the constituent ES cells undergo differentiation. The spontaneous emergence of cells expressing these markers occurred only following long-term EB culture. This indicates a lag in the signalling normally required for PGC specification. In vivo, the lack of BMP4, its receptor (ALK-2) or downstream signalling molecules (Smad 1 and 5), results in the absence of PGCs in embryos. Therefore, in order to enhance PGC specification in our in vitro system, we have added BMP4 into the culture media. Under these conditions, the emergence of cells expressing PGC markers occurs at both an apparently higher efficiency and in a shorter time period. This suggests that BMP4 response pathways are present within the EB context and, when activated, can direct PGC specification. Thus, by recapitulating an in vivo physical and biochemical environment, we are able to direct PGC lineage specification in vitro.

74 ANATOMICAL ABNORMALITIES IN CALVES PRODUCED BY NUCLEAR TRANSFER

Two limitations currently restrict the acceptability and adoption of bovine cloning as a commercial reality. The first of these is its low rate of efficiency and the second is that some of the cloned calves are not healthy. Abnormalities in the placenta are thought to contribute to many of the losses in early gestation; however, less is known of the pathology of clone deaths in the perinatal period. To date, the majority of perinatal deaths have been attributed to the “large offspring syndrome” characterized by increased birth weight and a range of morphological abnormalities thought to be associated with in vitro culture and manipulation. This report describes multi-systemic abnormalities in aborted, stillborn, and neonatal genetically modified and unmodified cloned calves weighing less than 60 kg at birth and aged between 6 months gestation and 3 weeks postnatal, generated in various experiments. Three of 14 genetically modified cloned calves had cystic renal dysplasia and osteopetrosis. All three and a fourth had irregular nodular, fibrotic livers with biliary abnormalities. Another two had marked flexion of the fetlock joints. Eleven calves derived from an unmodified cloned cell line by nuclear transfer had nodular, fibrotic livers with biliary anomalies, 9 of 11 had cystic renal dysplasia and cardiomegaly, two had osteopetrosis, and two had contracted tendons. In addition, three calves had polymicrocerebral gyri, two had retinal dysplasia, and one had an aortic aneurysm. Only one calf from a second unmodified cloned cell line produced by nuclear transfer had no significant congenital abnormalities. All calves were negative for bovine virus diarrhea virus (BVDV) by competitive-antigen ELISA, and by virus isolation and no BVDV antibodies were detected by AGID assay. Furthermore, all cell lines and media used were negative for BVDV by virus isolation. Two calves were tested and found to be negative for Akabane virus and Aino virus. There are very few reports of the pathological abnormalities of cloned animals. Similar multi-systemic abnormalities have not been found in non-cloned calves, but several analogous conditions occur in humans, including Simpson-Golabi-Behmel and Zellwegers syndromes. Further ultrastructure studies and genetic analysis are needed to investigate the mechanisms of these multi-systemic disorders, which may ultimately elucidate mechanisms for improved reprogramming and increase the efficiency of generating cloned animals with somatic cells by nuclear transfer.

119 THE LOCALIZATION OF A METHYL BINDING DOMAIN PROTEIN (MBD4) IN MURINE AND BOVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS

The presence of MBD4, a member of the methyl binding domain family, was investigated in both murine and bovine oocytes and pre-implantation embryos. MBD4 is the only MBD family member that is involved in DNA repair but not active in transcriptional repression or in the formation of complexes with histone deacetylase complexes (HDACs). It contains a mismatch-specific glycosylase domain that acts to repair G:T mismatches within a CpG context. Bovine cumulus oocyte complexes were collected from abattoir-derived ovaries, matured in vitro and used for IVF as described previously (Ruddock et al. 2004 Biol. Reprod. 70, 1131–1135). Samples were analyzed at all steps in this process. Murine oocytes were collected from superovulated mice (C57BL6 × CBA) and subjected to conventional IVF. A polyclonal antibody derived in the rabbit against human peptides from specific regions of MBD4 (Imgenex, San Diego, CA, USA) was used to localize MBD4 protein. This antibody was tested at a variety of concentrations against both human HL60 leukemia cells and bovine embryos. Staining of HL60 cells was optimum at 32–64 μg/mL and embryos at 64 μg/mL. Briefly, the staining protocol consisted of fixing cells and zona-free oocytes or embryos in 4% paraformaldehyde for 15 min, followed by 15 min in 0.1% Triton X-100. Primary antibody incubation was performed overnight at 4°C. Embryos were then washed in blocking buffer for 1 hr prior to incubation at 4°C in mouse anti-rabbit IgG conjugated to FITC in blocking buffer for 30 min in the dark. Lastly, embryos were incubated in 10 μg/L Hoescht 33342 for 15 min, and then washed and mounted with Vectashield (Vector Labs, Burlingame, CA, USA). Negative controls contained no primary antibody. Mounted cells/embryos were viewed by epifluorescence microscopy. MBD4 was found to be expressed in both murine and bovine oocytes and pre-implantation embryos. In the cow, faint nuclear expression was detected at the 2-cell stage, followed by exclusion of the protein from the nucleus until the blastocyst stage of development. At this stage, staining was primarily nuclear and quite intense. In the mouse, staining was cytoplasmic at the 2 pronuclear stage, but was then concentrated in the nucleus from the 2-cell stage onward. It will be interesting to determine if this is due to the different timing of embryonic genome activation between the two species, hence implying a role for MBD4 in this important biological process. Further investigations are underway to compare the subcellular localization of the other MBD proteins in both species during preimplantation development and to identify a role for MBD4 in embryonic genome activation.

235 THE INVESTIGATION OF mRNA EXPRESSION OF SEVERAL CHROMATIN REMODELLING GENES DURING BOVINE PREIMPLANTATION DEVELOPMENT

The efficiency of obtaining live calves from somatic cell nuclear transfer remains quite low. One factor implicated in this failure is inadequate chromatin remodelling of the donor nucleus. Five Polycomb group (PcG) genes were investigated as potential remodelling factors in bovine oocytes and preimplantation embryos. These genes (Cbx6, Eed, Edr1, Yy1, and Zfp144) are involved in transcriptional activation and cell cycle regulation. We hypothesize that inadequate expression may cause the developmental abnormalities seen following cloning. This study is aimed at characterizing normal expression, prior to comparative studies with cloned embryos. Three single abattoir-derived in vitro-matured (IVM) oocytes or in vitro-produced (IVP) embryos from each of the following stages: 2-cell, 4-cell, 8-cell, 16–32 cell, morula, Day 7 blastocyst, and Day 8 hatched blastocyst, were studied. Messenger RNA was isolated from individual samples with Dynabeads (Dynal, Inc., Lake Success, NY, USA) and then cDNA was created and amplified with a SMART cDNA synthesis kit (BD Biosciences Clontech, Palo Alto, CA, USA). Products were diluted 1:10 and used to amplify target genes by PCR. PCR products were sequenced for confirmation of identity. All amplified embryo samples expressed the housekeeping genes Poly(A) polymerase and actin. Similarly, all embryos up to the 8-cell stage expressed GDF9, an oocyte-specific gene, while IFN-tau, involved in maternal recognition of pregnancy, was expressed in one morula and all blastocyst samples. Cbx6 was not expressed at any stage. The other four genes were all expressed fairly consistently throughout the pre-implantation period. Eed transcript was detected in all samples, with the exception of one oocyte, one 4-cell embryo, and one 8-cell embryo. Edr1 transcript was detected in all samples except for two oocytes, one 16–32-cell embryo, and one Day 7 blastocyst. Yy1 was expressed in all but one oocyte, one 2-cell embryo, two 4-cell embryos, and one Day 7 blastocyst. Finally, Zfp144 transcript was detected in one oocyte and in all embryos until the 16–32 stage, and then was not detected until seen in one Day 7 and all Day 8 blastocysts. Cbx6, yet to be fully characterized in any species, is also known as the neuronal pentraxin receptor, and is involved in transport and clearance of synaptic debris. It is known to have the characteristic chromobox domain of the Cbx family, of which several family members play a role during pre-implantation development. Eed, Edr1, Yy1, and Zfp144 are expressed throughout the pre-implantation period, although levels of Zfp144 mRNA appear to drop during the embryonic genome activation and then reappear by the late blastocyst stage. This consistent expression may suggest a role for the proteins in chromatin remodelling or modulating patterns of gene expression in early development. Further studies are required to determine if these factors are expressed incorrectly in cloned embryos, potentially providing a link to the abnormalities observed post nuclear transfer.

Anti-neutrophil cytoplasm antibody IgG subclasses in Wegener's granulomatosis: a possible pathogenic role for the IgG4 subclass

A characteristic feature of Wegener's granulomatosis is the presence of antineutrophil cytoplasm antibodies (ANCA) to proteinase 3 (PR3). In vitro, ANCA activate neutrophils by co-ligating PR3 and FcgammaRIIa/IIIb receptors. ANCA are predominantly of the IgG isotype, and IgG1, IgG3 and IgG4 subclasses are particularly represented. To address the pathogenic role of individual ANCA-IgG subclass antibodies, patients' sera were screened using indirect immunofluorescence, enzyme-linked immunosorbent assay (ELISA) and subclass PR3-ELISA to identify patients with high titres of PR3-ANCA within the IgG1, IgG3 or IgG4 subclasses. Unfractionated ANCA-IgG and subclass fractions were isolated by affinity chromatography and compared for their capacities to stimulate superoxide production by primed human neutrophils. Donor neutrophils were analysed for constitutive and induced FcgammaRI expression by flow cytometry. The IgG1, IgG3 and IgG4 subclass fractions, isolated from three different ANCA sera, each stimulated superoxide production from neutrophils derived from multiple donors. Subsequently, IgG4 subclass fractions isolated from a further four ANCA positive sera demonstrated varying abilities to stimulate release of superoxide; unrelated to PR3-ANCA titre, neutrophil donor, or neutrophil FcgammaRI expression. The stimulation of superoxide release by IgG1- and IgG3-ANCA subclass fractions is consistent with the proposed mechanism of co-ligation of PR3 antigen and FcgammaRIIa/IIIb receptors. However, the demonstration of similar activity for the IgG4-ANCA subclass fractions isolated from some sera was unexpected. This activity was independent of neutrophil donor and expression of FcgammaRI, suggesting it was capable of activating neutrophils via constitutively expressed FcgammaRIIa/IIIb or co-ligation of other, unidentified, cell surface molecules.

Hypogalactosylation of serum IgG in patients with ANCA-associated systemic vasculitis

The triad of small vessel vasculitides (SVV) comprise Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and Churg-Strauss syndrome (CS). All three are associated with presence of circulating IgG antineutrophil cytoplasm antibodies (ANCA) which target autoantigens contained, primarily, within neutrophil azurophilic granules. The widely accepted model of pathogenesis suggests that ANCA activate cytokine-primed neutrophils within the microvasculature, leading to by-stander damage to endothelial cells, and rapid escalation of inflammation with recruitment of mononuclear cells. Activation may be initiated, in vitro, by the coligation of the PR3 or MPO antigen, translocated to the cell surface, and FcgammaRIIa/FcgammaRIIIb receptors. This suggests that the IgG subclass profile of ANCA and, possibly, its glycosylation status could influence the inflammatory mechanisms activated. The glycosylation status of total IgG isolated from the sera of patients with WG (13), MPA (6) and CSS (1) was determined by analysis of the released oligosaccharides. A deficit in IgG galactosylation is demonstrated for all patient samples, compared to controls. The mean percentage values for the agalactosylated (G0) oligosaccharides were 57% (SD +/- 9.71), 47% (SD +/- 4.25) and 28% (SD +/- 4.09) for WG, MPO and control samples, respectively. The G0 levels for polyclonal IgG isolated from the sera of both WG and MPA patients were significantly increased compared to controls (P < 0.0001). The major glycoform present therefore is agalactosylated (G0) IgG. In previous studies the G0 glycoform of IgG has been shown to bind and activate mannan binding lectin, and hence to activate the complement cascade, and to facilitate mannose receptor binding and the uptake of IgG complexes by macrophages and dendritic cells. Both of these activities could impact on the processing and presentation of self-antigens in autoimmune disease.

Surgical glove perforation in cardiac surgery

BACKGROUND

Recently, concern for the protection of health care employees and health care recipients has led to increasing awareness of transmitted infections. Sterile surgical gloves were tested to determine the incidence of perforations after being worn during procedures commonly performed by cardiac surgeons.

MATERIAL AND METHODS

In a prospective study conducted from January 15, 2000 through February 15, 2000, 953 gloves worn during cardiac surgery were evaluated for punctures. Pairs of sterile latex surgical gloves were collected over a period of one month. Routine tasks included mainly bypass and valve surgery. Impermeability was tested by means of a water retention test according to European standard EN 455 Part 1 performed on 954 (Manufix, Hartmann, Germany) latex gloves. A control group of 50 unused gloves was also evaluated for the presence of spontaneous leakage. Gloves were separated according to whether the wearer was an operator (254 gloves), first assistant (220 gloves), second assistant (272 gloves), or theatre nurse (207 gloves). Gloves with a known perforation occurring during the procedure were not included in the study.

RESULTS

There were no punctures in the 50 unused gloves. Punctures were detected in 66 of 254 (26.0 %) gloves used by operators, 49 of 220 (22.3 %) used by first assistants, 25 of 272 (9.2 %) used by second assistants, and 78 of 207 (37.7 %) used by theatre nurses. Some gloves had more than one puncture, accounting for the 244 holes detected (operators 75/244 = 30.7 %; first assistants 54/244 = 22.1 %; second assistants 28/244 = 11.5 %; theatre nurses 87/244 = 35.7 %). Sites of scalpel and suture needle injuries were most commonly the thumb (27.3 %) and pointer finger (42.1 %) of the non-dominant hand, followed by, in descending order: middle finger (10.2 %), other fingers (15.7 %), palm (3.8 %) and back of the hand (0.9 %).

CONCLUSION

The number of punctures that occur during cardiac operations is obviously higher than has so far been assumed. Therefore, cardiac surgeons should consider the incidence of unknown glove perforations when planning surgery in patients with infectious diseases.