Implications for sequencing of biologic therapy and choice of second anti-TNF in patients with inflammatory bowel disease: results from the IMmunogenicity to Second Anti-TNF therapy (IMSAT) therapeutic drug monitoring study

BACKGROUND

Anti-drug antibodies are associated with treatment failure to anti-TNF agents in patients with inflammatory bowel disease (IBD).

AIM

To assess whether immunogenicity to a patient's first anti-TNF agent would be associated with immunogenicity to the second, irrespective of drug sequence METHODS: We conducted a UK-wide, multicentre, retrospective cohort study to report rates of immunogenicity and treatment failure of second anti-TNF therapies in 1058 patients with IBD who underwent therapeutic drug monitoring for both infliximab and adalimumab. The primary outcome was immunogenicity to the second anti-TNF agent, defined at any timepoint as an anti-TNF antibody concentration ≥9 AU/ml for infliximab and ≥6 AU/ml for adalimumab.

RESULTS

In patients treated with infliximab and then adalimumab, those who developed antibodies to infliximab were more likely to develop antibodies to adalimumab, than patients who did not develop antibodies to infliximab (OR 1.99, 95%CI 1.27-3.20, p = 0.002). Similarly, in patients treated with adalimumab and then infliximab, immunogenicity to adalimumab was associated with subsequent immunogenicity to infliximab (OR 2.63, 95%CI 1.46-4.80, p < 0.001). For each 10-fold increase in anti-infliximab and anti-adalimumab antibody concentration, the odds of subsequently developing antibodies to adalimumab and infliximab increased by 1.73 (95% CI 1.38-2.17, p < 0.001) and 1.99 (95%CI 1.34-2.99, p < 0.001), respectively. Patients who developed immunogenicity with undetectable drug levels to infliximab were more likely to develop immunogenicity with undetectable drug levels to adalimumab (OR 2.37, 95% CI 1.39-4.19, p < 0.001). Commencing an immunomodulator at the time of switching to the second anti-TNF was associated with improved drug persistence in patients with immunogenic, but not pharmacodynamic failure.

CONCLUSION

Irrespective of drug sequence, immunogenicity to the first anti-TNF agent was associated with immunogenicity to the second, which was mitigated by the introduction of an immunomodulator in patients with immunogenic, but not pharmacodynamic treatment failure.

Adolescent with abdominal pain poorly responsive to analgesia

Case presentationA 14-year-old boy, with autism spectrum disorder, presented with a 1-day history of colicky abdominal pain, non-bilious vomiting, anorexia and loose normal-coloured stool. Two days previously, he had a poorly reheated takeaway chicken.On examination, body mass index (BMI) was >99th centile. He had inconsistent epigastric, periumbilical and umbilical tenderness, and guarding, with normal bowel sounds. Observations were within normal limits, but his pain was poorly responsive to paracetamol, ibuprofen, hyoscine butylbromide, codeine and morphine.Investigations are in table 1. On day 3, his temperature increased to 38.5° and a CT scan was performed, which showed concerning features (figure 1).

Primary care faecal calprotectin testing in children with suspected inflammatory bowel disease: a diagnostic accuracy study

OBJECTIVE

To determine the diagnostic accuracy of calprotectin to diagnose inflammatory bowel disease (IBD) in children in whom general practitioners (GPs) suspected IBD.

DESIGN

Prospective observational cohort study of a new calprotectin-based primary care referral pathway.

SETTING

48 GP practices and gastroenterology secondary care services at the Royal Devon and Exeter NHS Foundation Trust in the South-West of England, UK.

PATIENTS

195 children aged between 4 and 18 years referred on the pathway between January 2014 and August 2017 for investigation of gastrointestinal symptoms were included.

INTERVENTIONS

Primary-care-driven faecal calprotectin testing. Primary and secondary care records over 12 months from the point of calprotectin testing were used as the reference standard.

MAIN OUTCOME MEASURES

Diagnostic accuracy of calprotectin testing to detect IBD.

RESULTS

7% (13/195) tested patients were diagnosed with IBD. Using our prespecified cut-off of 100 µg/g, calprotectin had a diagnostic accuracy of 91% (95% CI 86% to 95%) with a sensitivity for distinguishing IBD from non-IBD of 100% (95% CI 75% to 100%), a specificity of 91% (95% CI 85% to 94%), a positive predictive value of 43% (95% CI 25% to 63%) and a negative predictive value of 100% (95% CI 98% to 100%). Calprotectin testing had no effect on the time to diagnosis, but a negative test contributed to saved referrals and was associated with fewer diagnostic tests in secondary care.

CONCLUSIONS

Calprotectin testing of children with suspected IBD in primary care accurately distinguishes IBD from a functional gut disorder, reduces secondary care referrals and associated diagnostic healthcare utilisation.

Extracorporeal photopheresis in the treatment of graft-versus-host disease: evidence and opinion

Despite significant advances in prevention and treatment strategies, graft-versus-host disease remains the most significant cause of morbidity and nonrelapse mortality after allogeneic hematopoietic cellular transplantation. Corticosteroids remain the standard frontline therapy for graft-versus-host disease; however, a considerable number of patients will not respond adequately and others will be significantly affected by adverse effects. Extracorporeal photopheresis is one of several secondary therapies which have shown promise in the clinical setting. While the procedure itself has been around for over 20 years, our understanding of the mechanisms from which therapeutic benefits are seen, and the population they are seen in, remains limited. In this article, we review the use of extracorporeal photopheresis for the treatment of graft-versus-host disease including details covering the procedure's mechanism of action, safety profile and clinical efficacy data.

Measured versus predicted energy expenditure in children with inactive Crohn's disease

INTRODUCTION

The aim of the study was to assess if the estimated average requirements for energy for normal children (EAR) and the Schofield equation could reliably predict energy requirements in children with inactive Crohn's disease (CD).

METHODS

Twenty-three children with inactive CD were studied, median age 14.3 years (range 7.8-16.9). Resting energy expenditure (REE) was measured by indirect calorimetry and compared with that predicted using the Schofield equation (BMR). Total energy expenditure (TEE) was measured using REE and a 3-day activity diary and compared with EAR.

RESULTS

REE ranged from 79% to 136% of BMR. Mean REE was not significantly greater than mean BMR (P=0.25 2-tailed t-test). TEE ranged from 72% to 163% of estimated average requirements for energy for children of that weight (EARw). EARw tended to underestimate TEE in large children and overestimate TEE in small children (Bland-Altman plot R=0.5, P=0.002). EARw was a poor predictor of TEE (R=0.35, P=0.1). EAR underestimated energy requirements by >500 kcal/day in 40% of the children.

CONCLUSIONS

The Schofield equation and EAR are unreliable methods of predicting total energy requirements in children with inactive CD with a significant potential to underestimate energy needs. When energy requirements were greater than EAR it was due to physical activity and body habitus rather than raised REE.

Integrated risk assessment or integrated risk management?

Problems of hazard assessment and risk assessment are at the present time the subjects of considerable discussion in the context of the Organisation for Economic Cooperation and Development (OECD) chemical management programs, within the European Community (EEC) and at national levels. A previous article (J. W. Hart and N. J. Jensen, 1990, Regul. Toxicol. Pharmacol. 11, 123-131) discussed the inherent limitations of the hazard assessment of chemicals. The elements of hazard and risk assessment have been described by Bro-Rasmussen (In Risk Assessment of Chemicals in the Environment, M. L. Richardson, Ed., Chap. 24, pp. 437-450, Royal Society of Chemistry, London, 1988). This article is an attempt to illustrate the different elements in hazard and risk assessments in specific risk management areas and to indicate the limitations in these processes. This analysis indicates that there are different requirements for a risk assessment, which depend on its specific purpose. In particular, problems related to the integration of different approaches--and the stage at which integration is possible--are discussed. While the principle subject of the discussion is risk assessment, many of the elements concerned are also a part of priority setting, and this subject is also discussed briefly.

The myth of the final hazard assessment

Hazard assessment is a basic tool used in the evaluation and regulation of chemicals, but in spite of this there are many different interpretations of the scope and function of a hazard assessment. Starting from a discussion of the essential elements and conceptual frames involved, an attempt is made to identify the sources of uncertainty that are inherent in a hazard assessment. Problems identified include unambiguous identification of the chemical source, the routes of exposure, and the possible targets to be considered. Inadequacies in effects data are frequent, but unlike many of the other sources of uncertainty, these are often compensated for by the use of safety factors when setting quantitative limits for human or environmental exposure. The inherent uncertainties in the process make periodic revisions of any hazard assessment process inevitable, as new knowledge on routes of exposure and targets becomes available.

New light on the cholodny-went theory

The existence of different auxin sensitivities in epidermal and subepidermal tissues (KV Thimann, CL Schneider 1938 Plant Physiol 25: 627-641) suggests a refinement to the Cholodny-Went theory which overcomes some of the difficulties associated with it. A model is presented to account for the inverse tropic responses of shoots and roots through differences in the respective locations of the auxin-sensitive tissues.

The role of the apex in normal and tropic growth of sunflower hypocotyls

Regional growth in vertical and horizontal etiolated sunflower hypocotyls from which the apical hook tissue had been either partly or wholly excised, was measured 24 h later, the regions having been demarcated with resin beads. Removal of the cotyledons (an excision which included the distal end of the shoot apex) had little effect on growth during this period but excision of the apical hook significantly reduced growth. In vertically orientated seedlings, removal of half of the hook severely reduced growth in all other growing regions and removal of the entire hook totally inhibited growth. This inhibition of growth was not a consequence of the removal of the region of growth but a consequence of the removal of a region on which growth was dependent. In horizontal seedlings, the situation was more complex inasmuch as a horizontal orientation itself induced growth in previously non-growing regions. This new growth was localised in its extent and was not as severely affected by progressive excision of the hook as was growth in vertical seedlings. The results are discussed in terms of overall growth co-ordination in the hypocotyl.

Image Analysis of Geo-Induced Inhibition, Compression, and Promotion of Growth in an Inverted Helianthus annuus L. Seedling

The growth responses of a sunflower seedling (Helianthus annuus L.), subjected to repeated inversion, were characterized by time-lapse recording in conjunction with video image analysis. The investigation revealed a characteristic response pattern and established that the directional movement of the seedling is achieved by both inhibition and stimulation of growth in the normal growing regions. The complex growth changes in contiguous regions of the hypocotyl are such as seem to be inexplicable in terms of an environmentally imposed gradient of a single growth substance.

Is there a role for the apex in shoot geotropism?

Experiments with horizontal etiolated sunflower (Helianthus annuus L.) seedlings supported centrally such that both apical and basal ends are free to react to geostimulus, revealed that the apical end commences curvature 1 to 2 hours earlier than the basal end. The later curvature in the basal region is a consequence of the absence of growth in the initial period rather than merely slower growth. A comparison of zonal growth rates in a vertical and a horizontal seedling confirmed that geostimulus induces a renewal of growth in a region where growth had ceased. Removing the apical half of the hypocotyl showed that the curvature resulting from this growth initiation in the basal region is dependent on attachment to the apical region. Evidence that this dependence is unlikely to be due to energy deficiency is adduced. The prior response of the apical end to geostimulus and the apically dependent later initiation of new growth in the basal region are compatible with the delay inherent in message transport from apex to base and are considered as evidence for apical involvement in the totality of the seedling's georesponse.

Statistics of the mouse bone-marrow micronucleus test: counting, distribution and evaluation of results

The distribution of historical control results from male mice tested in the bone-marrow micronucleus test was used to optimize counting procedures and to develop decision rules for evaluating test results. The ratio of normochromatic to polychromatic erythrocytes followed a normal distribution, while the incidence of micronucleated polychromatic and normochromatic erythrocytes followed a binomial distribution. Recommendations for the number of cells to be scored per animal and for the evaluation of results are based on these distributions and the two-hypothesis multiple-decision approach of Selby and Olsen (1981).

The positive hook: the role of gravity in the formation and opening of the apical hook

Photographic observations on germinating seedlings of Lepidium sativum L., Cucumis sativus L., and Helianthus annuus L. showed that the hypocotyl hook is not present in the seed but forms during the early stages of growth. Evidence that gravity plays a major role in inducing curvature of the hypocotyl, and in maintaining the hook once it has been formed, was obtained from clinostat experiments, from the use of morphactin to remove geotropic sensitivity and from inversion of seedlings to change the direction of the geostimulus. In L. sativum and H. annuus gravity perception seemed to be the only mechanism responsible for hook formation. In C. sativus hook formation was additionally aided by the mode of emergence of the cotyledons from the seed coat but gravity played an indirect role in regulating such emergence. Further evidence that hook formation is linked to a georesponse was derived from a comparison of hypocotyl development in wild-type Arabidopsis thaliana seedlings with that of an ageotropic mutant, hook formation being found to occur only in the wild type. Hook formation and maintenance is discussed in terms of contrasting geosensitivity between the apical and basal ends of the hypocotyl and it is suggested that light-induced hook opening is a reversal to a condition of uniformly negative georesponse throughout the hypocotyl.

Induction of micronuclei in the mouse. Revised timing of the final stage of erythropoiesis

The early effects of X-rays, vincristine, cyclophosphamide, quinacrine dihydrochloride, cycloheximide, actinomycin D and hydroxyurea on the induction of micronuclei in mouse bone-marrow erythrocytes were studied. A significant increase in the incidence of micronuclei in polychromatic erythrocytes was seen as early as 5 h after a single treatment with vincristine, 6 h after treatment with X-rays and 10 h after treatment with cyclophosphamide. The cell kinetics of the mouse erythropoietic system described by Cole et al. (1981) can be modified to fit these results. According to this revised model, the final mitosis takes place only 5 h before the expulsion of the nucleus.

Pharmacokinetics and distribution of the new antihypertensive agent pinacidil in rat, dog and man

1. The antihypertensive agent pinacidil was rapidly, and almost completely, absorbed following oral administration of 0.5 mg/kg of the [14C]pinacidil monohydrate to rats and dogs. The half-life was about 1 and 2 h in the two species, respectively. A bioavailability of 80% of unchanged pinacidil in the rat suggests a first-pass effect in this species. 2. After oral and intravenous administration of [14C]pinacidil about 85% of the radioactivity was recovered in the urine and 15% in the faeces in rats and dogs; 80-90% was excreted during the first 24 h. Autoradiographic studies in the rat showed similar distributions after oral and intravenous administration. 3. An oral dose of 5 or 10 mg pinacidil monohydrate was rapidly absorbed in healthy volunteers and had a pharmacokinetic profile very similar to that found in rats and dogs. Concomitant food ingestion did not change the bioavailability of the drug.

Calcium-binding protein in sieve tube exudate

A calcium-binding macromolecule, with an estimated molecular weight greater than 100,000, was detected in phloem exudate from Cucurbita maxima and related species. The macromolecule was a component of sieve tube sap, rather than a contaminant leached from cell walls or cut parenchyma cells during exudate collection. The protein nature of this macromolecule was deduced from its size, lability, susceptibility to proteolytic digestion, and by the dependence of calcium-binding activity on thiol-protecting agents. This protein is distinct from the major proteins of exudate and does not appear to be related to calmodulin.

Heterogeneity in phloem protein complements from different species : Consequences of hypotheses concerned with P-protein function

Protein subunits present in phloem exudate from 17 cultivars, 5 species and 3 genera of the Cucurbitaceae have been fractionated by SDS-gel electrophoresis. The degree of difference in the phloem protein patterns appears to reflect the taxonomic relationships of the plants: there were major differences among genera, significant differences and similarities among species, and relatively few differences among cultivars of a single species. A representative of another family (Acer pseudoplatanus; Aceraceae) provided a completely different electrophoretic pattern. Each plant displayed a consistent protein pattern, irrespective of the organ from which exudate was obtained or the age and physiological status of the plant. Neither complete etiolation nor transition to the flowering phase effected any change in phloem proteins. The differences in phloem proteins between plants and the unusual properties of major subunits from different protein complements, render improbable many of the present ideas concerning the origin and function of P-protein.

A study of three preventive approaches to low back injury

The prevention of low back injuries in industry has traditionally been attempted by (1) careful selection of workers, (2) good training in safe lifting, and (3) designing the job to fit the worker (ergonomics). One hundred ninety-one low back injuries were analyzed to determine the effectiveness of each preventive approach. The results indicate that the common selection techniques, as they are being used today, are not an effective control for low back injuries. Similarly, training on safe lifting procedures, as it is being administered today, is not an effective control for low back injuries. It was determined that a worker is three times more susceptible to low back injury if exposed to excessive manual handling tasks. The ergonomic redesign of these tasks to reduce the manual handling exposure represents a partial control for low back injuries.

The isolation and some properties of a lectin (Haemagglutinin) from Cucurbita phloem exudate

The occurrence of high haemagglutinating (lectin) activity in phloem exudate from three cucurbit species is reported. The protein responsible for this lectin activity in Cucurbita maxima Duch. has been isolated by cation exchange chromatography on Sepharose and identified by gel electrophoresis. The lectin showed agglutinating activity at concentrations as low as 0.1 μg/ml. No sugar, including those transported in the phloem of these species, interacted with agglutination. The lectin could not be extracted from cucurbit seed, but appeared in 5-day old seedlings. The possible role of a lectin in the sieve element is discussed.

The heterogeneity of phloem exudate proteins from different plants: A comparative survey of ten plants using polyacrylamide gel electrophoresis

Proteins in sieve tube exudate from Ricinus communis L., Acer pseudoplatanus L., Aesculus hippocastanum L., Cucumis melo L., and two cultivars each of Cucumis sativus L., Cucurbita pepo L. and Cucurbita maxima Duchesne were fractionated and compared using polyacrylamide gel electrophoresis. Striking differences in major exudate proteins were displayed among the genera and species examined. Even cultivars within a single species, although showing general similarities, differed in some prominent proteins. Estimated molecular weights of the major exudate proteins from each plant are presented. The effects of reducing and chaotropic agents on the aggregation and subunit composition of exudate proteins from Cucumis sativus have been investigated. The problems involved in relating structure, function and biochemistry of P-protein are discussed.

A comparative analysis of phloem exudate proteins from Cucumis melo, Cucumis sativus and Cucurbita maxima by polyacrylamide gel electrophoresis and isoelectric focusing

Proteins in sieve tube exudate from Cucumis melo L., Cucumis sativus L. and Cucurbita maxima Duch. were analysed by gel electrophoresis and isoelectric focusing. Estimated molecular weights and isoelectric points for the major and minor proteins from each plant species are presented. Electrophoresis revealed striking differences between the protein complements of exudatc from the two genera investigated. Similarly, although a few exudate proteins from the two species of Cucumis possessed identical molecular weights, several major proteins were peculiar to each species. Isoelectric focusing of proteins in exudate samples from the three plants confirmed the marked differences in their protein complements. Furthermore, focusing also revealed differences between cultivars of Cucumis sativus. Both Cucumis sativus and Cucurbita maxima possessed relatively large amounts of basic proteins; these were absent in exudate from Cucumis melo. The implications of these results are discussed in relation to present concepts regarding the interrelationships and possible functional roles of P-proteins.

Studies on the possible occurrence of actomyosin-like proteins in phloem

Extracts of large quantities of petioles and of isolated vascular tissues of Heracleum mantegazzianum have been analysed for actomyosin-like contractile proteins. Concentrated preparations, subjected to a standard isolation and purification procedure for actomyosin, failed to demonstrate either superprecipitation or viscosity changes in response to the addition of ATP and divalent cations. In addition, ATPase activities in phloem and xylem extracts have been fractionated by gel electrophoresis and characterised with regard to their substrate specificity, pH optima and ion requirements. Phloem extracts provide two phosphatases: one is non-specific in its substrate requirements; the other is a nucleoside triphosphatase but is stimulated only by monovalent cations and is also present in xylem extracts. All the enzymes are strongly inhibited by divalent cations and do not possess any of the characteristics of ATPases associated with contractile systems. The results are discussed in relation to the postulated involvement of contractile proteins in the translocation of sugars in phloem.

P-Protein in sieve elements : I. Ultrastructure after treatment with vinblastine and colchicine

The ultrastructure of P1 and P2 proteins in the sieve elements of Heracleum mantegazzianum is described. P1-protein tubules are closely associated with stacks of membranes, are often linked by short cross-bridges, and occasionally display a hexagonal packing. Incubation with the alkaloids vinblastine and colchicine had no discernible effects on the ultrastructure of the sieve elements at various stages during differentiation. Evidence for and against any similarities between P1-protein tubules and cytoplasmic microtubules is discussed.

Colchicine-binding protein from phloem and xylem of a higher plant

Colchicine has been demonstrated by ion-exchange and by gelfiltration assay to bind to a protein fraction derived from the higher plant Heracleum mantegazzianum. Colchicine-binding protein from a plant source was much more unstable than tubulin from animal preparations. The tissues of Heracleum vary in their content of colchicine-binding activity. No activity was obtained from non-vascular tissue. Phloem has at most, twice as much activity as xylem. The significance of these results is discussed in relation to a proposed degree of homology between P protein of phloem and microtubule protein.

Regulation of sulfate uptake by amino acids in cultured tobacco cells

The sulfur requirements of tobacco (Nicotiana tabacum L. var. Xanthi) XD cells grown in chemically defined liquid media can be satisfied by sulfate, thiosulfate, l-cyst(e)ine, l-methionine or glutathione, and somewhat less effectively by d-cyst (e) ine, d-methionine or dl-homocyst (e)ine. Sulfate uptake is inhibited after a 2 hr lag by l-cyst (e)ine, l-methionine, l-homocyst(e)ine or l-isoleucine, but not by any of the other protein amino acids, nor by d-cyst(e)ine. l-cyst(e)ine is neither a competitive nor a non-competitive inhibitor of sulfate uptake. Its action most closely resembles apparent uncompetitive inhibition. Inhibition of sulfate uptake by l-cyst(e)ine can be partially prevented by equimolar l-arginine, l-lysine, l-leucine, l-phenylalanine, l-tyrosine or l-tryptophan, but is little affected by any of the other protein amino acids. The effective amino acids are apparent competitive inhibitors of l-cyst(e)ine uptake after a 2 hr lag. Inhibition of sulfate uptake by l-methionine cannot be prevented, nor can uptake of l-methionine be inhibited by any single protein amino acid. The results suggest the occurrence of negative feedback control of sulfate assimilation by the end products, the sulfur amino acids, in cultured tobacco cells.