Effect of expiratory positive airway pressure on tidal volume during non-invasive ventilation

During non-invasive ventilation (NIV), tidal volume ( V_t) will depend upon the difference between inspiratory and expiratory positive airway pressure (IPAP and EPAP, respectively), provided the respiratory muscles are relaxed and the lungs and chest wall therefore move along their passive pressure-volume curves. To test this hypothesis, we studied the effect of increasing EPAP during pressure-controlled modes of NIV in 30 long-term ventilator users (10 each with scoliosis, obesity hypoventilation or neuromuscular disorders). While maintaining the same IPAP, addition of 5 cmH₂O of EPAP reduced mean V_t by 167 ml; 10 cmH₂O reduced V_t by 367 ml. This pattern was seen in all three patient groups. EPAP has several potential advantages, for example maintaining upper airway patency, preventing basal atelectasis and facilitating triggering. EPAP does, however, appear to reduce V_t. Decreasing EPAP is an alternative to increasing IPAP if measurements of gas exchange during NIV indicate that ventilation is inadequate.

Long-term non-invasive ventilation in muscular dystrophy

Long-term non-invasive ventilation (NIV) was introduced in the 1980s, initially mainly for patients with poliomyelitis, muscular dystrophy (MD) or scoliosis. The obesity-hypoventilation syndrome has since become the commonest reason for referral to most centres providing home-NIV. Patients with MD are numerically a much smaller part of the workload, but as their disease progresses the need for ventilatory support changes and they require regular comprehensive assessment of their condition. We have examined the trend in MD use of home-NIV in our unit over the last 25 years. The number of new referrals appears to be stabilizing at around 20-25 over a 5-year period, equivalent to approximately 0.5 per 100,000 of population per year. The mean age at commencement of home-NIV is now 37.5 years, with 5-year survival rates of 70-75%. Ten-year survival rates are just over 40%. The distance of usual place of residence from our unit is fairly stable, currently at a mean of 27 km. Excellent survival rates mean that patients with MD, while numerically small, are likely to remain an important part of the workload of centres providing home-NIV. Our data should prove useful in the planning of future services for this group of patients.

The indications, efficacy and adverse events of rituximab in a large cohort of patients with juvenile-onset SLE

Background

B cells drive antibody formation and T cell activation. This study aimed to describe the clinical indications, efficacy and adverse events (AEs) for the B-cell depleting agent, rituximab, in a large cohort of children with lupus.

Methods

Prescribing records and the UK JSLE Cohort Study database identified rituximab use.

Results

Sixty-three patients received 104 courses of intravenous rituximab over a 10-year period. Patients were aged 12.2 (IQR 9.0–13.9) years at diagnosis and 50 (79%) were female. They had disease for 1.4 (0.2–3.0) years at the time of rituximab. Lupus nephritis was the most common indication (36% of first courses). Clinical biomarkers, 2.5 (1.6–4.3) months after treatment, demonstrated a statistically significant improvement in ESR, C3, C4, creatinine, albumin, haemoglobin, anti-dsDNA titres and urine albumin:creatinine ratio. IgG, IgA and IgM levels decreased ( p < 0.01). Oral corticosteroid dose significantly reduced after rituximab (dose before 0.26 (0.09–0.44) mg/kg, after 0.17 (0.09–0.30) mg/kg; p = 0.01)). AEs occurred in 19 (18%) of all courses including; delayed second dose (8%), Ig replacement (2%) and infusion reactions (6%; anaphylaxis 2%). The global BILAG score showed a trend toward improvement (before 4.5 (2.0–9.0), after 3.0 (2.0–5.0); p = 0.16).

Conclusion

Rituximab improves disease activity in children with lupus and serious AEs are infrequent. Controlled studies are required.

New insights into the pathogenesis and management of lupus in children

Systemic lupus erythematosus (SLE) is the archetypal systemic autoimmune disease, characterised by inflammation causing a wide spectrum of major clinical manifestations that may affect any organ. Childhood-onset SLE (cSLE) is more severe with greater damage and drug burden than adult-onset SLE. Understanding the pathogenesis of cSLE is a key step in directing medical management. The dysregulated immune system, that in health is usually vital in protecting the body from infection, contributes significantly to the disease process. Improved knowledge of disease mechanism will help to identify potential targets for novel agents and the identification of new biomarkers of disease activity. This review will present current knowledge of the innate and adaptive immune responses in cSLE and the optimal patient management that aims to control the disease. Innate immune dysregulation includes the overexpression of interferon-α, dendritic cell activation, neutrophil extracellular traps and phagocyte abnormalities. The classical adaptive immune system is over activated in lupus with excessive autoantibody production due to abnormalities in B and T cell regulation. Novel biologic medications are being developed to specifically target these areas with the ultimate aim of improving the long-term outlook and quality of life for children living with Lupus.

Unmet needs in the measurement of blood pressure in primary care

BACKGROUND

Blood pressure (BP) monitoring in UK children at risk of hypertension takes place predominantly in secondary and tertiary care.

OBJECTIVES

To investigate (i) the availability of paediatric BP equipment in primary care (PC) and (ii) the confidence of PC professionals in measuring and interpreting children's BP.

METHODS

103 PC practices were approached to complete a questionnaire. BP equipment availability and confidence with BP measurement and interpretation were recorded (interval scale 1-10). Cuff size and equipment type were documented.

RESULTS

95 (92%) practices responded; 40/95 possessed paediatric BP cuffs. 35/51 devices were validated for paediatric use. Median (IQR) confidence in BP measurement was 7 (2-8). Confidence in BP interpretation was 3 (2-6), though this improved if normal ranges were provided (8 (6-9), p<0.01).

CONCLUSIONS

Investment in appropriate equipment and education is required to allow PC to successfully monitor BP in children.

Allele-specific silencing of mutant Ataxin-7 in SCA7 patient-derived fibroblasts

Polyglutamine (polyQ) disorders are inherited neurodegenerative conditions defined by a common pathogenic CAG repeat expansion leading to a toxic gain-of-function of the mutant protein. Consequences of this toxicity include activation of heat-shock proteins (HSPs), impairment of the ubiquitin-proteasome pathway and transcriptional dysregulation. Several studies in animal models have shown that reducing levels of toxic protein using small RNAs would be an ideal therapeutic approach for such disorders, including spinocerebellar ataxia-7 (SCA7). However, testing such RNA interference (RNAi) effectors in genetically appropriate patient cell lines with a disease-relevant phenotype has yet to be explored. Here, we have used primary adult dermal fibroblasts from SCA7 patients and controls to assess the endogenous allele-specific silencing of ataxin-7 by two distinct siRNAs. We further identified altered expression of two disease-relevant transcripts in SCA7 patient cells: a twofold increase in levels of the HSP DNAJA1 and a twofold decrease in levels of the de-ubiquitinating enzyme, UCHL1. After siRNA treatment, the expression of both genes was restored towards normal levels. To our knowledge, this is the first time that allele-specific silencing of mutant ataxin-7, targeting a common SNP, has been demonstrated in patient cells. These findings highlight the advantage of an allele-specific RNAi-based therapeutic approach, and indicate the value of primary patient-derived cells as useful models for mechanistic studies and for measuring efficacy of RNAi effectors on a patient-to-patient basis in the polyQ diseases.

Children and adolescents with SLE: not just little adults

Juvenile-onset systemic lupus erythematosus (JSLE) represents 15–20% of all SLE cases. Whilst features of this chronic complex multisystem autoimmune disorder are highly variable, children and adolescents generally present with a more severe illness than adults and accrue greater disease damage over time. JSLE has a less striking female preponderance and differs from the adult form in pattern of major organ manifestations. Corticosteroids are used in almost all children with JSLE along with the majority requiring additional immunosuppressive medications. Making the diagnosis early and optimizing disease control are essential to ensure that normal childhood and adolescent development is not impeded. In this young population, special consideration must be given to the long-term sequelae of the disease and treatment-related toxicity. There is a current lack of paediatric-specific controlled trials and treatment strategies are generally guided by adult data. The enormous psychological and social impact of the disease and its treatments upon the child or young person and their family necessitates a comprehensive, holistic, specialized multidisciplinary approach to managing JSLE.