Expression of myxovirus-resistance protein A: a possible marker of muscle disease activity and autoantibody specificities in juvenile dermatomyositis.

AIMS: To evaluate the relationship between expression of myxovirus-resistance protein A (MxA) protein on muscle biopsies by immunohistochemistry and disease activity in juvenile dermatomyositis (JDM) patients. Also, another aim was to investigate whether the expression of MxA is related with myositis-specific autoantibodies (MSA) status in JDM patients. METHODS: 103 patients (median aged 6.3, interquartile range 0.5-15.9) enrolled in the Juvenile Dermatomyositis Cohort and Biomarker Study (JDCBS). Muscle biopsies were stained with MxA and scored. Clinical data at initial presentation were collected and autoantibodies were analysed. Multiple linear regression analysis was performed to estimate the association between MxA expression on muscle fibres and muscle disease activity, and MSA status. RESULTS: Expression of MxA protein on JDM samples was identified in 61.2%. There was a significant association between MxA scores and Childhood Myositis Assessment Scale (CMAS) (P = 0.002), and Manual Muscle Testing of Eight Muscles (MMT8) (P = 0.026). CMAS and MMT8 scores were significantly lower in the group of patients with strong MxA expression. MxA scores differed according to MSA subgroups (P = 0.002). Patients with positive nuclear matrix protein 2 autoantibodies had strong MxA expression, whereas anti-melanoma differentiation-associated gene 5 positive patients had no or weak MxA expression. CONCLUSIONS: This study reveals the significant association between level of MxA expression on muscle fibres and clinical measures of muscular disease activity in JDM patients and MSA status. This confirms type I interferonopathies in muscle fibres of JDM patients which could help with improving treatment outcome in JDM patients and underscoring the distinct pathophysiological pathways in different MSA status.

Histological heterogeneity in a large clinical cohort of juvenile idiopathic inflammatory myopathy: analysis by myositis autoantibody and pathological features.

AIM: Juvenile idiopathic inflammatory myopathies have been recently reclassified into clinico-serological subgroups. Myopathological correlates of the subgroups are incompletely understood. METHODS: We studied muscle biopsies from 101 children with clinically and serologically defined juvenile idiopathic inflammatory myopathies from the UK JDM Cohort and Biomarker Study by applying the international JDM score tool, myopathological review and C5b-9 complement analysis. RESULTS: Autoantibody data were available for 90/101 cases with 18/90 cases positive for anti-TIF1γ, 15/90 anti-NXP2, 11/90 anti-MDA5, 5/90 anti-Mi2 and 6/90 anti-PmScl. JDM biopsy severity scores were consistently low in the anti-MDA5 group, high in the anti-Mi2 group, and widely distributed in the other groups. Biopsies were classified histologically as perifascicular atrophy (22/101), macrophage-rich necrosis (6/101), scattered necrosis (2/101), clustered necrosis (2/101), inflammatory fibre invasion (2/101), chronic myopathic change (1/101), diffuse endomysial macrophage infiltrates (40/101) and minimal change (24/101). MDA5 cases segregated with the minimal change group and showed no capillary C5b-9-deposition. The Mi2 group displayed high severity scores and a tendency towards sarcolemmal complement deposition. NXP2 and TIF1γ groups showed a variety of pathologies with a high proportion of diffuse endomysial macrophage infiltrates and a high proportion of capillary C5b-9 deposition. CONCLUSION: We have shown that juvenile idiopathic inflammatory myopathies have a spectrum of histopathological phenotypes and show distinct complement attack complex deposition patterns. Both correlate in some cases with the serological subtypes. Most cases do not show typical histological features associated with dermatomyositis (e.g. perifascicular atrophy). In contrast, more than half show relatively mild histopathological changes.

Risk factors for Taenia saginata cysticercus infection in cattle in the United Kingdom: A farm-level case-control study and assessment of the role of movement history, age and sex.

Bovine cysticercosis is caused by Taenia saginata cysticercus, the larval stage of the human tapeworm Taenia saginata. Recent European initiatives have highlighted the poor sensitivity of current surveillance for this parasite in cattle at slaughter; calling for more targeted, risk based and cost effective methods of T. saginata cysticercus detection. The aim of this study was to provide evidence that could inform such improved meat inspection activities in the United Kingdom (UK). The study included three components: (i) a farm-level case control study; (ii) the characterization of the network of movements of T. saginata cysticercus infected and non-infected animals, and an assessment of the strength of association between having passed through a farm that had previously originated an infected animal and the risk of infection; (iii) the assessment of the relationship between bovine age and gender and risk of infection. Abattoir records and cattle movement history data were used to identify farms of likely acquisition of infection (case farms) and a suitable control group. A questionnaire was used to gather farm-level characteristics and logistic regression was carried out to identify farm-level risk factors for the production of cattle found to be infected at slaughter. The case-control study provided evidence that farms situated close to a permanent potential source of human faecal contamination, and farms which used manure from animals other than cattle, were at higher risk of producing cattle later found to be infected with T. saginata cysticercus at slaughter. No other farm characteristics were identified as a risk factor for this. Analysis of the networks of animal movements showed that some individual farms played a key role as a source of T. saginata cysticercus infection; it was estimated that cattle with a history of being on a farm which previously appeared in the movement history of an infected animal were 4.27 times (P<0.001; 95% CI: 3.3-5.52) more likely to be diagnosed with T. saginata cysticercus infection at meat inspection. Male cattle aged 20 months or younger at the time of slaughter were found at lower risk of T. saginata cysticercus infection by comparison to other sex or age groups of cattle. These results, in combination with the consultation of experts and stakeholders, led to the conclusion that abattoir-based surveillance in low T. saginata cysticercus prevalence settings, such as Great Britain, could be made more targeted by stratifying cattle based on their individual movement history, sex and age characteristics.

Associations of toll-like receptor (TLR)-4 single nucleotide polymorphisms and rheumatoid arthritis disease progression: an observational cohort study.

OBJECTIVE: To examine the associations of toll-like receptor (TLR)-4 single nucleotide polymorphisms (SNPs) with disease progression in rheumatoid arthritis (RA). METHODS: A total of 1188 RA patients were genotyped for TLR4 SNPs (rs1927911, rs11536878, and rs4986790). Measures of disease activity were examined, including Disease Activity Score-28 (DAS28), Multidimensional Health Assessment Questionnaire (MD-HAQ), Clinical Disease Activity Index (CDAI), and Simplified Disease Activity Index (SDAI). Genetic associations with these longitudinal measures were examined using generalized estimating equations in both univariate and multivariate analyses. Analyses were then stratified by antigen specific anti-citrullinated peptide antibody (ACPA) status including antibody to citrullinated fibrinogen and citrullinated histone H2B. RESULTS: Disease activity measures progressed less over time in the homozygous minor allele group of rs1927911 including DAS28 (p<0.001), CDAI (p=0.008), and MD-HAQ (p=0.015) in univariate analysis and DAS28, CDAI and SDAI in multivariate analysis. Disease activity progression among those homozygous for the minor allele tended to be lower in the groups with positive ACPA though major differences by autoantibody status were not identified. There were no associations of TLR4 rs11536878 and rs4986790 SNPs with RA disease activity progression. CONCLUSIONS: In this population, TLR4 rs1927911 genotypes are associated with disease activity independent of other covariates.

Associations of alcohol use with radiographic disease progression in African Americans with recent-onset rheumatoid arthritis.

OBJECTIVE: To investigate the associations of alcohol consumption and radiographic disease progression in African Americans with recently diagnosed rheumatoid arthritis (RA). METHODS: Patients with RA included in the study were participants in the Consortium for the Longitudinal Evaluation of African Americans with Early Rheumatoid Arthritis (CLEAR) registry. Patients were categorized based on self-reported alcohol consumption; those consuming < 15 beverages per month versus those with ≥ 15 per month. Association of radiographic disease progression over a 1-year to 3-year period of observation with alcohol consumption was evaluated using multivariate generalized estimating equations. RESULTS: Of 166 patients included in the study, 39% reported that they had never consumed alcohol. Of the 61% who had consumed alcohol, 73% reported that they consumed on average < 15 alcoholic beverages per month and 27% reported consuming ≥ 15 per month. In multivariate analysis, consumption of ≥ 15 alcoholic beverages per month was associated with an increased risk of radiographic disease progression (p = 0.017). There was no evidence of a relationship in those consuming < 15 beverages per month (p = 0.802). CONCLUSION: There appears to be a dose-dependent relationship between alcohol use and radiographic disease progression in RA. Individuals who consume 15 or more alcoholic beverages per month may have faster rates of radiographic joint damage than those with lower levels of consumption.

A case of cranial fasciitis masquerading as acute mastoiditis.

OBJECTIVE: We report a case of infection against a background of pre-existing cranial fasciitis. METHOD: Case report and review of world literature on cranial fasciitis. RESULTS: Cranial fasciitis of childhood is a benign condition and a rare variant of nodular fasciitis. We present the case of a 10-week-old infant with symptoms and signs consistent with a subperiosteal abscess complicating acute mastoiditis. Subsequent findings showed this to be an infection against a background of pre-existing cranial fasciitis. CONCLUSION: To our knowledge, this is the first such reported case in the literature. Knowledge of the distinctive histopathological features, coupled with an awareness of the condition, are crucial to establishing a definitive diagnosis of cranial fasciitis and, in turn, to instituting appropriate management. The aetiopathogenesis of the condition remains unclear.

Neutralisation of the clotting activity of Australian snake venoms by snake plasma.

Plasmas from Pseudonaja textilis and Notechis scutatus were tested in vitro for their ability to neutralise the procoagulant activity, in human plasma, of nine elapid venoms. Pseudonaja textilis plasma inhibited the procoagulant activity of all Pseudonaja species and in one taipan (Oxyuranus scutellatus). However there was no inhibitory activity against any from the Notechis species. Plasma from Notechis scutatus exhibited no inhibitory activity against any Notechis species, including self, only weak inhibition against the Pseudonaja species and, again, total inhibition of Oxyuranus scutellatus. Thus, protection of a species from the effects of its own venom does not appear to be universal.

Platelet indices during normal pregnancy and pre-eclampsia.

Platelet count and mean platelet volume (MPV) were estimated in 349 normal pregnancies at various gestational stages, and in 30 cases of pre-eclampsia. A probability plot was constructed from these data using discriminant analysis of MPV versus platelet count for the pre-eclamptic versus normal pregnancies. The sensitivity for pre-eclampsia was 90% (27/30) and the specificity was 83.3%. This plot may be of use in confirming risk of pre-eclampsia.

Elevated mid-trimester hCG and maternal lupus anticoagulant.

An association is described between women with lupus anticoagulant and abnormal prenatal serum screening results. Three cases of positive second-trimester serum screening for Down syndrome, with karyotypically normal fetuses, in women demonstrated to have lupus anticoagulant are presented. Serum screening positivity was principally due to a disproportionately elevated maternal serum human chorionic gonadotrophin (hCG) level. In each case, early, severe intrauterine growth restriction was documented, with only one fetus surviving the neonatal period. As maternal lupus anticoagulant may have a profoundly adverse effect on the course of pregnancy, we suggest that an elevated hCG level on prenatal screening prompt consideration of maternal lupus anticoagulant testing if ultrasonography demonstrates an otherwise normal singleton gestation and the fetal karyotype is normal.

Antenatal diagnosis and management of fetomaternal alloimmune thrombocytopenia.

Fetomaternal alloimmune thrombocytopenia (FMAT) arises from maternal-fetal platelet antigen incompatibility, which stimulates the production of maternal immunoglobulin G (IgG) platelet-specific antibody. Transplacental passage of this antibody results in fetal platelet destruction and consequent thrombocytopenia. Sequelae of thrombocytopenia may be observed in both the fetus and neonate with intracranial hemorrhage occurring in approximately 10 to 30% of affected infants. No antenatal universal screening test is currently available to detect the 50% of cases occurring in the first pregnancy. The recurrence rate in subsequent pregnancies is 75 to 85%, with a tendency to increasing disease severity. Paternal platelet genotyping is recommended to assist in risk counseling following an affected pregnancy. Prenatal therapeutic strategies are aimed at elevating the fetal platelet count in affected pregnancies and thus decreasing hemorrhagic sequelae. The most effective treatment regimen is uncertain, but encouraging results are reported with the use of maternal intravenous gamma globulin. We report our experience in the antenatal diagnosis and management of FMAT.

Antenatal platelet antibody testing by flow cytometry--results of a pilot study.

BACKGROUND: Maternal platelet antibodies can cause fetomaternal alloimmune thrombocytopenia (FMAT), which has significant mortality and morbidity even in a first pregnancy. Prenatal diagnosis of FMAT has not previously been possible in the first affected pregnancy. STUDY DESIGN AND METHODS: Using flow cytometry, a sensitive, inexpensive test for the detection of platelet antibodies has been developed. It was adapted for use as a possible antenatal screening test, and 600 pregnant women were tested in a pilot study. RESULTS: In the study group, two women tested positive for platelet-specific IgG antibodies, one for anti-HPA-1a and the other for anti-HPA-1a with anti-HLA. In each case, the fetus was found to be affected in utero, and treatment was initiated before successful delivery. Another woman was shown to have a platelet-reactive autoantibody without IgG specificity, and her infant was unaffected. A total of 95 (15.8%) of the women tested had HLA antibodies alone, and the majority demonstrated IgG specificity. On follow-up of 62 infants born to these women, none had thrombocytopenia; thus HLA antibodies were not shown to lead to FMAT in this study. CONCLUSION: The flow cytometry-based test for platelet antibodies can detect clinically significant maternal antibodies, and it may be that early diagnosis and treatment in utero can enhance outcome in FMAT. A population screening program is planned to determine the predictive power of this test, in addition to its sensitivity, specificity, and efficiency.

Prediction of neonatal alloimmune thrombocytopenia using PCR.

Neonatal alloimmune thrombocytopenia (NAIT) is a potentially fatal condition and in the majority of cases is associated with maternal antibodies to the HPA-1a (PLA1) haplotype. Early diagnosis in utero can enhance survival rates. The application of DNA genomic analysis and PCR technology for the determination of the HPA-1a/HPA-1b (PLA1/PLA2) locus is described and applied in a family study where the fetus was diagnosed to have NAIT. This rapid technique differentiated between the 3 haplotypes HPA-1a/HPA-1a, HPA-1b/HPA-1b and HPA-1a/HPA-1b using the polymorphism at base 196 of the GPIIIa gene. This is the first Australian report on the establishment of this technology for platelet genotype typing and the application in the diagnosis of NAIT. This technique can be performed on DNA extracted from any nucleated cells and avoids the difficulty of requiring fetal platelets for serological typing when NAIT is suspected. The PCR technique of genomic DNA analysis has an important application in the prediction and management of this potentially severe condition.

Detection of lupus anticoagulant--an Australian perspective.

The detection of lupus anticoagulant is important in laboratory evaluation of patients with thrombotic tendencies. The aim of this workshop was to assess the effectiveness of Australian laboratories in detecting these antibodies and assess the tests used. Fourteen laboratories took part in the exercise, held as a Workshop of the National Meeting of Australian Medical Laboratory Scientists in 1990. Seven unknown plasmas were distributed for testing prior to the meeting. While 100% correctly identified 3 strong inhibitors and a moderate strength inhibitor, the detection rate for specific individual tests varied from 38-100%. The detection rate for 2 weak inhibitors varied from 0-50%. Of the most commonly performed tests the least sensitive was the dilute Russell's viper venom time and the most sensitive was the tissue thromboplastin inhibition test, however, the degree of sensitivity seemed dependent on the source of thromboplastin. In some laboratories the Kaolin clotting time, with variations, was more sensitive. All participants correctly identified a factor VIII inhibitor as not of the lupus type. The false positive detection rate was 0%. All but one of the participating laboratories used 2 or more phospholipid dependent tests for the analysis of lupus anticoagulant (LA) which is in keeping with current international guidelines.

A fatal case of necrotizing enterocolitis in a neonate with polyagglutination of red blood cells.

An infant of 30 weeks gestation developed necrotizing enterocolitis (NEC) 8 days after birth and died 2 days later after a fulminating course. During her illness she received two blood transfusions, both of which produced sub-optimal rises in her haemoglobin and were associated with evidence of haemolysis. Retrospective analysis demonstrated T antigen (Tk) polyagglutination of the infant's red blood cells and donor plasma. Although bacterial cultures were negative throughout the course of the illness in this case, T antigen exposure is associated with certain anaerobic infections and with severity of NEC. Infants with NEC should be regularly screened for T antigen exposure and if this test is positive, plasma (immunoglobulin) containing infusions should be avoided.

Continuously tunable diode-pumped UV-blue laser source.

Continuous tunability and high efficiency are obtained from an intracavity-doubled optical parametric oscillator pumped by a frequency-doubled diode-pumped Nd:YAG laser. The optical parametric oscillator is tunable from 760 to 1040 nm with 30% efficiency, giving 380-520-nm tunability after intracavity doubling with 40% efficiency.

3-W continuous-wave diode-pumped 532-nm laser.

A cw diode-pumped Nd:YAG laser is mode locked at 80 MHz and produces 5.5 W of output at 1.064 microm. Intracavity frequency doubling by using KTP produces 3 W of mode-locked output at 0.532 microm.

Efficient optical parametric oscillator at 1.6 microm.

We extend the operating regime of diode-pumped Nd:YAG lasers into the eye-safe region at 1.61 microm by using an efficient optical parametric oscillator in KTP. Total energy conversion efficiencies of the 1.06-microm pump to 1.61-microm signal and 3.1-microm idler approach 40%, with 25% converson to 1.61microm alone. This device has a wallplug efficiency of 0.8%, producing 2.5-mJ output energies at an eye-safe wavelength, and is readily scalable to higher energies.