Suspending Tonsillectomy: The Effects on Primary and Secondary Acute Care in Scotland

For the first six months of 2001, tonsillectomy operations were effectively suspended in Scotland. This was due to concern regarding the potential transmission of vCJD prions by surgical instruments, and the subsequent gradual introduction of disposable instruments. The number of patients awaiting tonsillectomy therefore increased and theoretically there should have been an increase in the number of tonsillitis episodes in the community, or even in the number of tonsillitis-related complications seen in secondary care. We examined for these effects using available national data sources which record primary and secondary care activity. No increases in the incidences of acute tonsillitis or tonsillitis-related complications were found for this period. The reasons and implications are discussed.

Somatic, positive and negative domains of the Center for Epidemiological Studies Depression (CES-D) scale: a meta-analysis of genome-wide association studies

BACKGROUND

Major depressive disorder (MDD) is moderately heritable, however genome-wide association studies (GWAS) for MDD, as well as for related continuous outcomes, have not shown consistent results. Attempts to elucidate the genetic basis of MDD may be hindered by heterogeneity in diagnosis. The Center for Epidemiological Studies Depression (CES-D) scale provides a widely used tool for measuring depressive symptoms clustered in four different domains which can be combined together into a total score but also can be analysed as separate symptom domains.

METHOD

We performed a meta-analysis of GWAS of the CES-D symptom clusters. We recruited 12 cohorts with the 20- or 10-item CES-D scale (32 528 persons).

RESULTS

One single nucleotide polymorphism (SNP), rs713224, located near the brain-expressed melatonin receptor (MTNR1A) gene, was associated with the somatic complaints domain of depression symptoms, with borderline genome-wide significance (p discovery = 3.82 × 10-8). The SNP was analysed in an additional five cohorts comprising the replication sample (6813 persons). However, the association was not consistent among the replication sample (p discovery+replication = 1.10 × 10-6) with evidence of heterogeneity.

CONCLUSIONS

Despite the effort to harmonize the phenotypes across cohorts and participants, our study is still underpowered to detect consistent association for depression, even by means of symptom classification. On the contrary, the SNP-based heritability and co-heritability estimation results suggest that a very minor part of the variation could be captured by GWAS, explaining the reason of sparse findings.

The relationship and effects of golf on physical and mental health: a scoping review protocol

INTRODUCTION

Golf is a sport played in 206 countries worldwide by over 50 million people. It is possible that participation in golf, which is a form of physical activity, may be associated with effects on longevity, the cardiovascular, metabolic and musculoskeletal systems, as well as on mental health and well-being. We outline our scoping review protocol to examine the relationships and effects of golf on physical and mental health.

METHODS AND ANALYSIS

Best practice methodological frameworks suggested by Arksey and O'Malley, Levac et al and the Joanna Briggs Institute will serve as our guide, providing clarity and rigour. A scoping review provides a framework to (1) map the key concepts and evidence, (2) summarise and disseminate existing research findings to practitioners and policymakers and (3) identify gaps in the existing research. A three-step search strategy will identify reviews as well as original research, published and grey literature. An initial search will identify suitable search terms, followed by a search using keyword and index terms. Two reviewers will independently screen identified studies for final inclusion.

DISSEMINATION

We will map key concepts and evidence, and disseminate existing research findings to practitioners and policymakers through peer-reviewed and non-peer reviewed publications, conferences and in-person communications. We will identify priorities for further study. This method may prove useful to examine the relationships and effects of other sports on health.

Targeting ADAM-17 with an inhibitory monoclonal antibody has antitumour effects in triple-negative breast cancer cells

Background:

Identification and validation of a targeted therapy for triple-negative breast cancer (TNBC), that is, breast cancers negative for oestrogen receptors, progesterone receptors and HER2 amplification, is currently one of the most urgent problems in breast cancer treatment. EGFR is one of the best-validated driver genes for TNBC. EGFR is normally activated following the release of ligands such as TGFα, mediated by the two MMP-like proteases ADAM (a disintegrin and metalloproteinase)-10 and ADAM-17. The aim of this study was to investigate the antitumour effects of a monoclonal antibody against ADAM-17 on an in vitro model of TNBC.

Methods:

We investigated an inhibitory cross-domain humanised monoclonal antibody targeting both the catalytic domain and the cysteine-rich domain of ADAM17-D1(A12) in the HCC1937 and HCC1143 cell lines.

Results:

D1(A12) was found to significantly inhibit the release of TGFα, and to decrease downstream EGFR-dependent cell signalling. D1(A12) treatment reduced proliferation in two-dimensional clonogenic assays, as well as growth in three-dimensional culture. Furthermore, D1(A12) reduced invasion of HCC1937 cells and decreased migration of HCC1143 cells. Finally, D1(A12) enhanced cell death in HCC1143 cells.

Conclusion:

Our in vitro findings suggest that targeting ADAM-17 with D1(A12) may have anticancer activity in TNBC cells.

Trends in weighted vital signs and the clinical course of 44,531 acutely ill medical patients while in hospital

BACKGROUND

little is known about the changes and trends of individual vital signs during the course of acute illness in hospital.

METHODS

the weighted points of the VitalPAC Early Warning Score (ViEWS) were assigned to each vital sign value measured on 44,531 acutely ill medical patients while they were hospitalized in the Thunder Bay Regional Health Sciences Centre, Ontario, Canada. These ViEWS weighted vital signs were averaged for every 24 hour period for five days after admission and five days before death or discharge and then combined to obtain an approximation of the trajectory of each vital sign while in hospital.

RESULTS

compared with the other vital signs, the ViEWS weighted points for respiratory rate increase the most in patients who died in hospital and decrease the most in survivors. Combining respiratory rate with the weighted points for any of the other vital signs reduced rather than increased their monitoring performance.

CONCLUSION

trends in respiratory rate, measured by observation at the bedside and given a ViEWS weighting is the best predictor of clinical outcome; minor changes predicted clinical outcome several days in advance.

To what extent does g impact on conceptual, practical and social adaptive functioning in clinically referred children?

BACKGROUND

Previous analyses have found variable results when evaluating the size of the association between intellectual ability and adaptive functioning in individuals with impaired function.

METHODS

We assessed the association between intellectual ability measured as a latent higher-order g and three different areas of adaptive functioning in a sample of clinically referred individuals with low IQ.

RESULTS

Regressing g on conceptual, practical and social adaptive functioning yielded standardised regression coefficients of 0.65, 0.60 and 0.51 respectively.

CONCLUSIONS

Results suggests that even at low levels of ability, increments in g still have important consequences for human functioning. Further, the influence of g may not be equally strong across different areas of human functioning.

Comparison of fluorodeoxyglucose uptake in symptomatic carotid artery and stable femoral artery plaques

BACKGROUND

Fluorine-18-labelled fluoroxdeoxyglucose (FDG) positron emission tomography (PET) has been used to evaluate atherosclerotic plaque metabolic activity, and through its uptake by macrophages is believed to have the potential to identify vulnerable plaques. The aims were to compare FDG uptake in carotid plaques from patients who had sustained a recent thromboembolic cerebrovascular event with that in femoral artery plaques from patients with leg ischaemia, and to correlate FDG uptake with the proportion of M1 and M2 macrophages present.

METHODS

Consecutive patients who had carotid endarterectomy for symptomatic, significant carotid stenosis and patients with severe leg ischaemia and significant stenosis of the common femoral artery underwent FDG-PET and histological plaque analysis. The voxel with the greatest activity in the region of interest was calculated using the Patlak method over 60 min. Plaques were dual-stained for CD68, and M1 and M2 macrophage subsets.

RESULTS

There were 29 carotid and 25 femoral artery plaques for study. The maximum dynamic uptake was similar in carotid compared with femoral plaques: median (range) 9·7 (7·1-12·2) versus 10·0 (7·4-16·6) respectively (P = 0·281). CD68 macrophage counts were significantly increased in carotid compared with femoral plaques (39·5 (33·9-50·1) versus 11·5 (7·7-21·3) respectively; P < 0·001), as was the proportion of M1 proinflammatory macrophages. The degree of carotid stenosis correlated with the maximum dynamic FDG uptake (rs  = 0·48, P = 0·008).

CONCLUSION

FDG uptake was no greater in symptomatic carotid plaques than in the less inflammatory femoral plaques. In patients on statin therapy. FDG uptake occurred in areas of significant arterial stenosis, irrespective of the degree of inflammation.

The high cost to health and social care of managing falls in older adults living in the community in Scotland

Background and aims

Estimate costs for health and social care services in managing older people in the community who fall.

Method and results

Analyses of predominantly national databases using cost of illness methodologies. In Scotland, 294,000 (34%) of people over 65 years and living in the community fall at least once a year. Of these 20%, almost 60,000 people contacted a medical service for assistance. There were almost 30,000 attendances at GP practices, over 36,100 calls to the Scottish Ambulance Service and 46,816 people presenting at A&E, with 16,549 admitted, 30% with a hip fracture. Mortality was high, 7% during the hospital stay, rising to over 12% at 1 year. Over 20% of patients were unable to return to their homes. Associated costs were over £470 million, with 60% incurred by social services, mainly providing long-term care. Cost per person falling was over £1720, rising to over £8600 for those seeking medical assistance. A hip fracture admission cost £39,490, compared with £21,960 for other falls-related admissions.

Conclusions

Transparent, robust cost information demonstrates the substantial burden of falls for health and social care services and should be a driver for implementing evidence-based interventions to reduce falls.

Platelet reactivity changes significantly throughout all trimesters of pregnancy compared with the nonpregnant state: a prospective study

OBJECTIVE

Platelets play an important role in the pathophysiology of uteroplacental disease and platelet reactivity may be an important marker of uteroplacental disease activity. However, platelet reactivity has not been evaluated comprehensively in normal pregnancy. We sought to evaluate platelet reactivity using a number of agonists at defined time points in pregnancy using a novel platelet assay and compare these with a nonpregnant cohort.

DESIGN

Prospective longitudinal study.

SETTING

Outpatient department of a large tertiary referral centre.

SAMPLE

Eighty participants with 30 nonpregnant women and 50 pregnant women assessed longitudinally.

METHODS

This was a prospective cohort study performed longitudinally throughout uncomplicated singleton pregnancies with participants recruited before 15 weeks of gestation. They were controlled for a number of factors known to affect platelet reactivity. Blood samples were obtained in each trimester. Thirty nonpregnant healthy female volunteers also had a platelet assay performed. A modification of standard light transmission aggregometry was used to assess platelet function, with light absorbance measured following the addition of five different agonists at submaximal concentrations. Dose-response curves were plotted for each agonist for the nonpregnant cohort and in each trimester for the pregnant cohort.

MAIN OUTCOME MEASURES

Dose-response curves and median effective concentration.

RESULTS

When compared with the nonpregnant controls a significant reduction was demonstrated in platelet reactivity to collagen during the first trimester of pregnancy (P < 0.0001). Platelet aggregation increased significantly from the first to third trimesters in response to collagen and arachidonic acid.

CONCLUSION

Platelet reactivity varies according to pregnancy state, gestational age and agonist. The finding that platelet reactivity is reduced in the first trimester of pregnancy may be useful for the interpretation of further studies examining the role of platelet reactivity in the first trimester of pregnancies that develop uteroplacental disease.

Mechanical testing of lid speculae and relationship to postoperative ptosis

AIMS

Postoperative lid malpositions are known complications of routine intraocular surgery and were previously attributed to the use of a bridle suture or the myotoxic effect of retrobulbar or peribulbar anaesthetics. However, lid malpositions are still seen under topical anaesthesia. Recent studies have implicated the lid speculum as a factor. Patients with narrower vertical palpebral apertures have been shown to develop postoperative ptosis more frequently, but the reason is unknown. This is the first study to determine the forces exerted by lid speculae over a range of palpebral apertures.

METHODS

Mechanical testing was undertaken using a Bose 3200 materials testing machine. Tests were undertaken on four disposable and four reusable speculae. The force used to compress each speculum was compared over a range of displacements. A two-sample t-test was used to compare the stiffness of the two types of speculum.

RESULTS

The stiffness of the reusable speculum was significantly greater than the disposable speculum (P=0.002). The stiffness of each speculum was greatest at the range of displacement corresponding to the narrower palpebral apertures.

CONCLUSIONS

Different speculae exert significantly different forces on patients' eyelids during surgery. The patients who experience the greatest compression from the speculae are those with the smallest palpebral apertures. This may explain why these patients are more likely to develop postoperative lid malpositions.

A survey of respiratory viruses in New Zealand horses

AIMS

To determine which viruses circulate among selected populations of New Zealand horses and whether or not viral infections were associated with development of respiratory disease.

METHODS

Nasal swabs were collected from 33 healthy horses and 52 horses with respiratory disease and tested by virus isolation and/or PCR for the presence of equine herpesviruses (EHV) and equine rhinitis viruses.

RESULTS

Herpesviruses were the only viruses detected in nasal swab samples. When both the results of nasal swab PCR and virus isolation were considered together, a total of 41/52 (79%) horses with respiratory disease and 2/32 (6%) healthy horses were positive for at least one virus. As such, rates of virus detection were significantly higher (p<0.001) in samples from horses with respiratory disease than from healthy horses. More than half of the virus-positive horses were infected with multiple viruses. Infection with EHV-5 was most common (28 horses), followed by EHV-2 (27 horses), EHV-4 (21 horses) and EHV-1 (3 horses).

CONCLUSIONS

Herpesviruses were more commonly detected in nasal swabs from horses with respiratory disease than from healthy horses suggesting their aetiological involvement in the development of clinical signs among sampled horses. Further investigation to elucidate the exact relationships between these viruses and respiratory disease in horses is warranted.

CLINICAL RELEVANCE

Equine respiratory disease has been recognised as an important cause of wastage for the equine industry worldwide. It is likely multifactorial, involving complex interactions between different microorganisms, the environment and the host. Ability to control, or minimise, the adverse effects of equine respiratory disease is critically dependent on our understanding of microbial agents involved in these interactions. The results of the present study update our knowledge on the equine respiratory viruses currently circulating among selected populations of horses in New Zealand.

Performance of TOTAL, in medical patients attending a resource-poor hospital in sub-Saharan Africa and a small Irish rural hospital

BACKGROUND

Recently a very simple, easy to remember early warning score (EWS) dubbed TOTAL has been reported. The score was derived from 309 acutely ill medical patients admitted to a Malawian hospital and awards one point for Tachypnea >30 breaths per minute, one point for Oxygen saturation <90%, two points for a Temperature <35°C, one point for Altered mental status, and one point for Loss of independence as indicated by the inability to stand or walk without help. TOTAL has an area under the receiver operator characteristic curve (AUROC) for death within 72 hours of 78%.

METHODS

We compared the performance of the TOTAL score in 849 medical patients attending a resource poor hospital in Uganda and 2935 patients admitted to a small rural hospital in Ireland.

RESULTS

TOTAL's AUROC for death within 24 hours was the same in both hospital populations: 85.1% (95% CI 78.6 - 91.6%) for Kitovu Hospital patients and 84.7% (95% CI 77.1 - 92.2%) for Nenagh Hospital patients.

CONCLUSION

The discrimination of TOTAL is exactly the same in elderly Irish patients as it is in young African patients. The score is easy to remember, easy to calculate, and works over a broad range of patients.

Immunogenicity of the hydrophilic region of the MUC1 mucin protein core

This report is an analysis of data relating to the epitopes of 28 murine monoclonal antibodies reactive with the protein core of human carcinoma-associated MUC1 mucins. All anti-MUC1 antibodies define epitopes of linear sequences of 3, 4 or 5 amino acids within the hydrophilic domain, APDTRPAP, which is expressed multiple times in a highly conserved 20 amino acid repeat sequence of the MUC1 core. The R residue is present in the epitopes defined by all of the 28 anti-MUC1 monoclonal antibodies. Epitopes of antibodies originally prepared against immunogens containing human milk fat globule membranes include the motif DTR in over 90% of the examples studied.

Solid-organ transplantation in older adults: current status and future research

An increasing number of patients older than 65 years are referred for and have access to organ transplantation, and an increasing number of older adults are donating organs. Although short-term outcomes are similar in older versus younger transplant recipients, older donor or recipient age is associated with inferior long-term outcomes. However, age is often a proxy for other factors that might predict poor outcomes more strongly and better identify patients at risk for adverse events. Approaches to transplantation in older adults vary across programs, but despite recent gains in access and the increased use of marginal organs, older patients remain less likely than other groups to receive a transplant, and those who do are highly selected. Moreover, few studies have addressed geriatric issues in transplant patient selection or management, or the implications on health span and disability when patients age to late life with a transplanted organ. This paper summarizes a recent trans-disciplinary workshop held by ASP, in collaboration with NHLBI, NIA, NIAID, NIDDK and AGS, to address issues related to kidney, liver, lung, or heart transplantation in older adults and to propose a research agenda in these areas.

P4-08-03: Serum Autoantibodies to Breast Cancer Associated Antigens Reflect Tumor Biology: An Opportunity for Early Detection & Prevention?

Autoantibodies (AABs) are produced as an immune response to abnormal ('non-self') cancer antigens. Previous studies have reported that AABs can be measured in the blood long before cancers are presently diagnosed, e.g., up to 4 years before screening mammography identified breast cancers and up to 5 years before screening CT detected lung cancers. EarlyCDT™-Lung is currently available as an aid to early detection of lung cancer in high risk patients and measures a panel of seven AABs to general cancer antigens and also lung cancer (LC) specific antigens. These AABs have previously been reported to be associated with the two main types of LC i.e., non-small cell and small cell LC. This study looked at AABs to 4 general cancer antigens to evaluate whether their levels reflected different biology in primary breast tumors.

Methods

770 patients presented with primary breast cancer to three centers (Nottingham, UK n=323; Munich, Germany n=320; Oklahoma, USA n=127); the median ages and ranges were 61 (26-82), 61 (20-88) & 65 (54-84) years, respectively. All had serum samples taken post-diagnosis and pre-treatment. The tumors were well characterized for histological grade, estrogen receptor (ER), progesterone receptor (PgR) and HER2 status. Serum samples were tested for AABs to four generic cancer antigens(Ags) (p53, SOX2, NY-ESO-1 and Annexin1) originally included as part of Oncimmune's EarlyCDT™-Lung assay. The AABs were measured by ELISA on the Oncimmune platform, and the EarlyCDT™-Lung cutoffs were used to determine positivity.

Results

131/770 (17%) of primary breast cancers showed elevated AAB levels to one or more of the limited panel of four generic antigens. Positivity for each AAB was correlated with histological grade, ER, PgR and HER2 status. The results, which were similar for each of the three centres, were combined, and the results are shown in Table 1 below.

CMRF44+ Dendritic Cells from Peripheral Blood Stem Cell Harvests of Patients with Myeloma as Potential Cellular Vectors for Idiotype Vaccination

The optimal conditions required to harvest dendritic cells (DC) for immunotherapy were investigated in a series of preliminary investigations using peripheral blood stem cell (PBSC) harvests and blood from patients with myeloma. There was no difference in the number of DC (CMRF44+, CD19-, CD14-) in PBSC mobilized with G-CSF (mean 0.28%, n = 7) compared with GM-CSF (mean 0.24%, n = 6) and apheresis itself did not concentrate DC. In longitudinal studies (n = 10), the peak DC count (day 12 post PBSC harvest) did not correlate with the peak CD34+ cell count or white cell count. A simple affinity purification of DC resulted in a mean 63-fold purification. Affinity enriched suspensions from normal blood contained more DC (mean = 18.8%; n = 5) than those from patients with myeloma (mean = 9.9%; n = 13). The percentage of DC with a lymphoid phenotype (CD11c-, CDw123hi+) was significantly higher in G-CSF mobilized PBSC harvests (22.7%; n = 6) than in peripheral blood samples from patients with myeloma (7.0%; n = 13; p = 0.01). DC endocytosis was normal and did not change throughout the course of the disease. Neither DC numbers nor subsets changed significantly between days 1 and 3 of culture. Current mobilization procedures, optimized for PBSC, need to be altered when harvesting DC.

An implementation of a spike-response model with escape noise using an avalanche diode

This paper introduces a novel probabilistic spike-response model through the combination of avalanche diode-generated Poisson distributed noise, and a standard exponential decay-based spike-response curve. The noise source, which is derived from a 0.35-μm single-photon avalanche diode (kept in the dark), was tested experimentally to verify its characteristics, before being combined with a field-programmable gate-array implementation of a spike-response model. This simple model was then analyzed, and shown to reproduce seven of eight behaviors recorded during an extensive study of the ventral medial hypothalamic (VMH) region of the brain. It is thought that many of the cell types found within the VMH are fed from a tonic noise synaptic input, where the patterns generated are a product of their spike response and not their interconnection. This paper shows how this tonic noise source can be modelled, and due to the independent nature of the noise sources, provides an avenue for the exploration of networks of noise-fueled neurons, which play a significant role in pattern generation within the brain.

Effect of respiration, talking and small body movements on blood pressure measurement

It is accepted that accuracy of auscultatory blood pressure (BP) measurement is influenced by measurement conditions. However, there is little comparative quantitative clinical data. The aim of this study was to provide these data. Auscultatory systolic and diastolic BPs (SBPs and DBPs) were measured in 111 healthy subjects under five different conditions (resting, deeper breathing, talking, head and arm movement). The measurement sequence was randomized, and repeated three times. BPs and their within-subject variabilities were compared with resting values. SBP and DBP changed significantly in comparison with the resting condition: decreasing by 4.4 and 4.8 mm Hg, respectively, with deeper breathing (both P<0.001), increasing by 3.7 and 5.0 mm Hg with opposite arm movement, and increasing by 5.3 and 6.2 mm Hg with talking (all P<0.001). The mean differences between deeper breathing and talking were 9.7 and 11.0 mm Hg for SBP and DBP. The within-subject variability for repeat measurement of SBP and DBP under resting condition were 3.7 and 3.2 mm Hg and increased for non-resting conditions (all P<0.05, except for DBP while talking). We have shown that measurement conditions significantly influence manual auscultatory BPs and their measurement variabilities, and we provide quantitative data to allow comparison of the effects.

Implications of attendance patterns in Northern Ireland for abdominal aortic aneurysm screening

INTRODUCTION

Evidence supports the introduction of an abdominal aortic aneurysm (AAA) screening programme. The aims of this study were to estimate future disease patterns and to determine the effect of the proportion attending on the programme's cost-effectiveness.

PATIENTS AND METHODS

The results of the local AAA screening programme were reviewed. Ultrasonic infrarenal aortic diameter of 30 mm was considered aneurysmal. Projected population numbers from the Department of Health and current disease prevalence were used to estimate future number of potential patients. The Multi-centre Aneurysm Screening Study (MASS) Markov model was used to calculate an incremental cost-effectiveness ratio (ICER) and 95% uncertainty intervals (UI), using a 30-year time horizon and 3.5% per annum discount, to determine the effect of attendance.

RESULTS

Men were recruited from August 2004 to May 2010. 13316 were invited for a scan and 5931 (44.5%) attended. 321 AAA were diagnosed, giving a prevalence of 5.4%, while 27 large AAA (0.46%) were repaired. The annual incidence of AAA until 2021 will range from 441 to 526, with an incidence of 40-48 large AAA, with both showing a gradual increase with time. Using this attendance rate, the ICER was calculated at £2350 per life-year gained (95% UI: £1620-£4290), or £3020 per quality-adjusted life-year gained (95% UI: £2080-£5500).

CONCLUSIONS

The prevalence of disease in this local AAA screening was similar to other studies. The low attendance will result in many AAA being missed, but will not impact greatly on the long-term cost-effectiveness.

The implementation of a self-administration of medication programmes within Older Persons Mental Health

This paper aims to report on the literature related to self-medication programmes that contributed to the development of an Older Persons Mental Health (OPMH) specific pathway for a self-administration of medication (SAM) programme. The traditional methods used within mental health inpatient environments to administer medication are paternalistic and resonant of the medical approach to care. There is a need to investigate innovative methods in the management of depression in older adults that reflect an individualized, innovative approach to redress the power imbalance for patients. Electronic databases were searched using the search strategy of Hek et al. to identify key themes in the implementation of self-administration programmes. Seven themes emerged from the literature review: the structure of SAM, assessments and risks associated with SAM, patient education, SAM and medication adherence, the patients' perspective, advantages and barriers to SAM, and professional issues. These findings were then used as the foundation for a project to develop an OPMH specific pathway for the implementation of SAM. There is a distinct lack of implementation of SAM programmes across the UK, especially within mental health services. Older Persons Mental Health is ready for the implementation of change in medicines management for older adults. Self-administration of medication can ensure all the principles of NHS plan relating to individualized person-centred care are achieved. Nurses have the opportunity to actively contribute to this process, facilitating and empowering those in their care to be experts within their journey and take control of their illness.

Association of microsatellite polymorphisms with immune responses to a killed Mycobacterium avium subsp. paratuberculosis vaccine in Merino sheep

AIM

To study the association of polymorphisms at five microsatellite loci with immune responses to a killed Mycobacterium avium subsp. paratuberculosis (Map) vaccine.

METHODS

Merino sheep (504 vaccinates and 430 unvaccinated controls) from a long-term Johne's vaccine trial undertaken on three different properties in the Central Tablelands of New South Wales, Australia, were genotyped for five microsatellite markers located in three immunologically significant chromosome regions. The marker loci included three from the major histocompatibility complex (MHC), namely DYMS1, OLADRB and SMHCC1; and one each from the solute carrier family 11 member 1 (SLC11A1), OVINRA1, and the interferon-γ (IFN-γ), o(IFN)-γ, gene regions. Associations between immune responses and genetic polymorphisms at the marker loci were examined by analysing both allelic and genotypic effects.

RESULTS

The o(IFN)-γ locus had only two alleles, whereas the other four loci exhibited extensive polymorphism, with the number of alleles ranging from 10 (OVINRA1) to 21 (DYMS1), resulting in 30-92 genotypes per locus. Heterozygosities varied between 37% (o(IFN)-γ) and 87% (SMHCC1), while information on polymorphic contents ranged from 0.31 (o(IFN)-γ) to 0.87 (DYMS1). Each of the three properties exhibited unique allelic and genotypic frequencies. Analysis of immune response data revealed strong antibody and IFN-γ responses as early as 2 months post-vaccination. Immune responses in control animals on all three properties remained consistently low, except for slightly elevated IFN-γ responses at a few time-points on two properties, concomitant with exposure to natural infection. Genotype-phenotype association analyses revealed a number of marker genotypes/alleles to be significantly associated with antibody and IFN-γ responses. However, the effects of only five genotypes (one each at DYMS1, OLADRB, SMHCC1, OVINRA1 and o(IFN)-γ) and three alleles (one each at o(IFN)-γ, DYMS1and OLADRB) on IFN-γ responses were consistent across the three properties.

CONCLUSION

Considering the significance of IFN-γ responses in protection against Map, it is possible that the genotypes/alleles identified might have a role in protective immune responses to natural Map infections, and further studies are warranted to confirm this.