Working while unwell: Workplace impairment in people with severe asthma.

BACKGROUND: Severe asthma affects quality of life; however, its impact on workplace productivity is poorly understood. OBJECTIVE: To compare workplace productivity-absenteeism and presenteeism-and impairment in daily activities in severe and non-severe asthma over time and identify characteristics associated with presenteeism in severe asthma. METHODS: The Severe Asthma Web-based Database is an ongoing observational registry from Australia, New Zealand and Singapore. At April 2017, 434 patients with severe asthma and 102 with non-severe asthma were enrolled (18-88 years; 59% female). Participants provided comprehensive clinical and questionnaire data at baseline and were followed-up every 6 months for 24 months. Absenteeism (percentage of time not at work), presenteeism (self-reported impairment at work) and impairment in daily activities outside work due to health problems in the last week were calculated. RESULTS: At baseline, 61.4% of participants with severe asthma and 66.2% with non-severe asthma under 65 years were employed. At younger ages (30-50 years), fewer severe asthma participants were employed (69% vs 100%). Presenteeism and impairment in daily activity were more frequently reported in severe asthma and in participants with poorer asthma control, poorer lung function and more past-year exacerbations (P < .01). Over time, deteriorating asthma control was associated with increasing presenteeism. Although absenteeism was not different between severe and non-severe asthma, worse asthma control was associated with absenteeism (P < .001). In participants with severe asthma, presenteeism was reported more frequently in those with poorer asthma control, poorer asthma-related quality of life and symptoms of depression or anxiety (P < .01). CONCLUSION AND CLINICAL RELEVANCE: Severe asthma was associated with impairment at work and outside the workplace. Improving asthma control and mental health may be important targets for optimizing workplace productivity in severe asthma. Presenteeism and absenteeism may represent key metrics for assessing intervention efficacy in people with severe asthma of working age.

Multiple centre evaluation study of ADAMTS13 activity and inhibitor assays.

INTRODUCTION: Accurate evaluation of ADAMTS13 activity is required for the diagnosis and clinical management of thrombotic microangiopathies, and commercial kits are available for routine laboratory use. METHODS: Our study compares the results from Technoclone (Technoclone GmbH, Austria) activity and Inhibitor kits with specialist laboratory reference methods (FRETS and ELISA IgG) and the impact of transporting frozen samples and comparison of results. RESULTS: This multicentre study identified differences in Technoclone activity results compared to specialist testing, which could potentially impact diagnosis. A change in the commercial kit during the study period appears to have rectified the detection levels. Frozen samples provided comparable results between sites. CONCLUSION: With close attention to normal ranges, commercial kits are suitable for use in the clinical diagnosis of thrombotic microangiopathies and frozen transportation of samples between sites is a suitable approach. However, a robust external quality control system is essential to provide an independent evaluation of changes in kit production.

Real-life effectiveness of omalizumab in severe allergic asthma above the recommended dosing range criteria.

BACKGROUND: Omalizumab (Xolair) dosing in severe allergic asthma is based on serum IgE and bodyweight. In Australia, patients eligible for omalizumab but exceeding recommended ranges for IgE (30-1500 IU/mL) and bodyweight (30-150 kg) may still receive a ceiling dose of 750 mg/4 weeks. About 62% of patients receiving government-subsidized omalizumab are enrolled in the Australian Xolair Registry (AXR). OBJECTIVES: To determine whether AXR participants above the recommended dosing ranges benefit from omalizumab and to compare their response to within-range participants. METHODS: Data were stratified according to dose range status (above-range or within-range). Further sub-analyses were conducted according to the reason for being above the dosing range (IgE only vs. IgE and weight). RESULTS: Data for 179 participants were analysed. About 55 (31%) were above recommended dosing criteria; other characteristics were similar to within-range participants. Above-range participants had higher baseline IgE [812 (IQR 632, 1747) IU/mL vs. 209 (IQR 134, 306) IU/mL] and received higher doses of omalizumab [750 (IQR 650, 750) mg] compared to within-range participants [450 (IQR, 300, 600) mg]. At 6 months, improvements in Juniper 5-item Asthma Control Questionnaire (ACQ-5, 3.61 down to 2.01 for above-range, 3.47 down to 1.93 for within-range, P < 0.0001 for both) and Asthma Quality of Life Questionnaire (AQLQ mean score (3.22 up to 4.41 for above-range, 3.71 up to 4.88 for within-range, P < 0.0001) were observed in both groups. Forced expiratory volume in one second (FEV1 ) improved among above-range participants. There was no difference in response between above-range and within-range participants. Above-range participants due to either IgE alone or IgE and weight had similar improvements in ACQ-5, AQLQ and FEV1 . CONCLUSIONS AND CLINICAL RELEVANCE: Patients with severe allergic asthma above recommended dosing criteria for omalizumab have significantly improved symptom control, quality of life and lung function to a similar degree to within-range participants, achieved without dose escalation above 750 mg.

Effectiveness and response predictors of omalizumab in a severe allergic asthma population with a high prevalence of comorbidities: the Australian Xolair Registry.

BACKGROUND: Severe asthma is a high impact disease. Omalizumab targets the allergic inflammatory pathway; however, effectiveness data in a population with significant comorbidities are limited. AIMS: To describe severe allergic asthma, omalizumab treatment outcomes and predictors of response among the Australian Xolair Registry participants. METHODS: A web-based post-marketing surveillance registry was established to characterise the use, effectiveness and adverse effects of omalizumab (Xolair) for severe allergic asthma. RESULTS: Participants (n = 192) (mean age 51 years, 118 female) with severe allergic asthma from 21 clinics in Australia were assessed, and 180 received omalizumab therapy. They had poor asthma control (Asthma Control Questionnaire, ACQ-5, mean score 3.56) and significant quality of life impairment (Asthma-related Quality of Life Questionnaire score 3.57), and 52% were using daily oral corticosteroid (OCS). Overall, 95% had one or more comorbidities (rhinitis 48%, obesity 45%, cardiovascular disease 23%). The omalizumab responder rate, assessed by an improvement of at least 0.5 in ACQ-5, was high at 83%. OCS use was significantly reduced. The response in participants with comorbid obesity and cardiovascular disease was similar to those without these conditions. Baseline ACQ-5 ≥ 2.0 (P = 0.002) and older age (P = 0.05) predicted the magnitude of change in ACQ-5 in response to omalizumab. Drug-related adverse events included anaphylactoid reactions (n = 4), headache (n = 2) and chest pains (n = 1). CONCLUSION: Australian patients with severe allergic asthma report a high disease burden and have extensive comorbidity. Symptomatic response to omalizumab was high despite significant comorbid disease. Omalizumab is an effective targeted therapy for severe allergic asthma with comorbidity in a real-life setting.

Sputum ADAM8 expression is increased in severe asthma and COPD.

BACKGROUND: Severe asthma and chronic obstructive pulmonary disease (COPD) are chronic inflammatory airway diseases in which the mechanisms are not fully understood. A disintegrin and metalloproteinase domain 8 (ADAM8) is an enzyme expressed on most leucocytes and may be important for facilitating leucocyte migration in respiratory disease. OBJECTIVE: To investigate ADAM8 mRNA and protein expression in asthma and COPD and its relationship between asthma severity and inflammatory phenotypes. METHODS: Induced sputum was collected from 113 subjects with asthma (severe n = 31, uncontrolled n = 39 and controlled n = 35), 20 subjects with COPD and 21 healthy controls. Sputum ADAM8 mRNA expression was measured by qPCR, and soluble ADAM8 (sADAM8) protein was measured in the sputum supernatant by validated ELISA. RESULTS: ADAM8 mRNA correlated with ADAM8 protein levels (r = 0.27, P < 0.01). ADAM8 mRNA (P = 0.004) and sADAM8 protein (P = 0.014) levels were significantly higher in both asthma and COPD compared with healthy controls. ADAM8 mRNA (P = 0.035) and sADAM8 protein (P = 0.002) levels were significantly higher in severe asthma compared with controlled asthma. Total inflammatory cell count (P < 0.01) and neutrophils (P < 0.01) were also elevated in severe asthmatic sputum. Although ADAM8 mRNA was significantly higher in eosinophilic and neutrophilic asthma (P < 0.001), sADAM8 did not differ between asthma inflammatory phenotypes. ADAM8 expression positively correlated with sputum total cell count and sputum neutrophils. CONCLUSIONS AND CLINICAL RELEVANCE: ADAM8 expression is increased in both severe asthma and COPD and associated with sputum total cell count and neutrophils. ADAM8 may facilitate neutrophil migration to the airways in severe asthma and COPD.

Rituximab for thrombotic thrombocytopenic purpura: benefit of early administration during acute episodes and use of prophylaxis to prevent relapse.

BACKGROUND: Rituximab has been documented in the treatment of acute (≤ 3 days from admission), relapsed/refractory thrombotic thrombocytopenic purpura (TTP) and given as prophylaxis in selected cases to prevent acute relapse. The precise timing of rituximab in acute TTP has not been determined. OBJECTIVE: To perform a retrospective analysis of rituximab use in a large TTP referral center over an 8-year period. PATIENTS/METHODS: We assessed response to treatment and outcome for all patients treated with rituximab, including 91 patients presenting with 104 episodes of acute TTP and 15 patients given rituximab as prophylaxis to prevent relapse. In the acute TTP group we assessed the benefit of giving early (≤ 3 days from admission) vs. later (> 3 days) rituximab. RESULTS: In acute de novo TTP, previously untreated with rituximab, rituximab was given ≤ 3 days from admission to 54 patients and > 3 days from admission to 32 patients. Earlier administration (≤ 3 days) was associated with faster attainment of remission (12 vs. 20 days, P < 0.001), fewer plasma exchanges (16 vs. 24, P = 0.03) and shorter hospital stay (16 vs. 23 days, P = 0.01). Eighty-two patients (95%) achieved complete remission within 14 days (4-52 days); four patients died acutely. Eleven out of 82 (13.4%) relapsed at a median of 24 months (4-49 months). Rituximab prophylaxis was associated with normalization of ADAMTS13 levels within 3 months in all but one case, with only one acute relapse at follow-up. CONCLUSIONS: Although limited by being retrospective and non-randomized, this study demonstrates the potential benefit of early administration of rituximab in acute TTP, and prophylactic use to prevent acute relapse.

Innate immune responses against Cryptosporidium parvum infection.

Cryptosporidium parvum infects intestinal epithelial cells and is commonly the parasite species involved in mammalian cryptosporidiosis, a major health problem for humans and neonatal livestock. In mice, immunologically mediated elimination of C. parvum requires CD4+ T cells and IFN-γ. However, innate immune responses also have a significant protective role in both adult and neonatal mice. NK cells and IFN-γ have been shown to be important components in immunity in T and B cell-deficient mice, but IFN-γ-dependent resistance has also been demonstrated in alymphocytic mice. Epithelial cells may play a vital role in immunity as once infected these cells have increased expression of inflammatory chemokines and cytokines and demonstrate antimicrobial killing mechanisms, including production of NO and antimicrobial peptides. Toll-like receptors facilitate the establishment of immunity in mice and are involved in the development of inflammatory responses of infected epithelial cells and also dendritic cells.

Effect of Fungicide Application on the Management of Avocado Branch Canker (Formerly Dothiorella Canker) in California.

Members of the Botryosphaeriaceae family have been associated with branch cankers of avocado trees (Persea americana) in California. Canker infections are initiated by spores entering the host plant through fresh wounds such as pruning wounds. With high-density planting becoming more common in the California avocado industry, more intensive pruning may increase the occurrence of branch canker. The objective of this study was to evaluate the preventive ability of some commercial fungicides belonging to different chemical families against fungal pathogens associated with avocado branch canker. Initially, 12 fungicides were tested in vitro for their effect on the inhibition of mycelial growth of three isolates of Dothiorella iberica and isolates (five per species) of Neofusicoccum australe, N. luteum, N. parvum, and Phomopsis sp. Subsequently, azoxystrobin, fludioxonil, metconazole, and pyraclostrobin, selected because of their low effective concentrations that reduce 50% of mycelial growth (EC50 values), and myclobutanil, selected for its high EC50 value, were tested in two field experiments. Azoxystrobin and fludioxonil were used in a premix with propiconazole and cyprodinil, respectively, in field trials. Significant differences (P < 0.05) were observed among fungicides in field trials. Azoxystrobin + propiconazole had the highest percent inhibition at 52 and 62% (internal lesion length) in trial 1 and trial 2, respectively, although this level of inhibition was not significantly different from that of metconazole. A significant correlation (r = 0.51, P < 0.05) was observed between internal lesion length data in the field experiment and EC50 data from in vitro fungicide screening. Application of azoxystrobin + propiconazole and metconazole can play a key role in protecting Californian avocado against fungi causing avocado branch canker.

Identification and Pathogenicity of Fungal Pathogens Associated with Stem-End Rot of Avocado in California.

Stem-end rot of harvested avocado fruit commonly occurs wherever the crop is cultivated. Multiple fungal species have been described as causal agents. To determine the causal pathogens of stem-end rot in California, fungal isolations were conducted from symptomatic fruit, and fungi were identified by morphological and molecular techniques. In 2010 and 2011, a total of 177 isolates were recovered from 290 avocado fruit collected from seven orchards in one of the major avocado growing areas in Southern California. The majority of isolates was identified as Neofusicoccum luteum (65%), with the remainder either as Colletotrichum gloeosporioides (33%) or Phomopsis sp. (2%). In a pathogenicity test, N. luteum caused significantly (P < 0.05) more severe stem-end rot than either C. gloeosporioides or Phomopsis sp. No significant (P > 0.05) differences in stem-end rot severity were observed between inoculations with N. luteum isolated from fruit stem-end rot and N. luteum or N. parvum isolated from branch cankers. This confirms that stem-end rot of avocado can be initiated by fungi causing branch cankers. Although low humidity and rainfall during much of the growing and harvest seasons in California are considered unfavorable conditions for the development of avocado stem-end rot, the identification of the causal pathogens is of value when decays have to be managed during outbreaks, and it stresses the importance of managing branch cankers.

Exacerbations of severe asthma.

Exacerbations occur frequently in severe asthma. They result in significant morbidity and can lead to hospitalization and death. Severe exacerbations can also lead to an accelerated decline in lung function. Phenotyping severe asthma can aid with both prognostication of exacerbation risk and maintenance treatment selection to minimize future risks of exacerbations in severe asthma. The rate of exacerbations differs by phenotype, and is most frequent in refractory eosinophilic asthma and early onset allergic asthma. Phenotype specific therapy can reduce exacerbations in both these forms of severe asthma. Exacerbations are multi-component events. Each exacerbation represents an opportunity to assess and target treatment to the domains of airway pharmacotherapy, self-management behaviour, risk factors, and relevant co-morbidities.

Soluble RAGE is deficient in neutrophilic asthma and COPD.

The receptor for advanced glycation end-products (RAGE) is a pattern-recognition receptor involved in the host response to injury, infection and inflammation. It is a membrane receptor, but also has soluble forms (sRAGE). Deficiencies in sRAGE are linked to heightened inflammation in various chronic conditions. We determined whether airway and systemic levels of sRAGE and the RAGE ligands HMGB1 (high-mobility group box-1) and serum amyloid A (SAA) are related to neutrophilic inflammation in asthma and chronic obstructive pulmonary disease (COPD). Bronchial lavage fluid from subjects with moderate-to-severe persistent asthma (n = 16) or COPD (n = 37), or from healthy controls (n = 18), was analysed for neutrophils, total sRAGE, endogenous secretory RAGE (esRAGE), HMGB1 and SAA. We also determined systemic levels of sRAGE in a separate group of asthmatic (n = 101) and COPD (n = 34) subjects. Subjects with neutrophilic asthma or COPD had undetectable levels of lung sRAGE, while levels of sRAGE in asthma/COPD without neutrophilia were similar to those in controls. Systemic sRAGE was significantly decreased in subjects with neutrophilic asthma or COPD compared with those without airway neutrophilia. There was significant positive correlation between total sRAGE and esRAGE in the lung and systemically. HMGB1 levels were similar in all subject groups, while SAA was below detectable levels. Neutrophilic airway inflammation in asthma and COPD is associated with reduced sRAGE.

Multicentre audit of inpatient management of acute exacerbations of chronic obstructive pulmonary disease: comparison with clinical guidelines.

BACKGROUND AND OBJECTIVE: Chronic obstructive pulmonary disease (COPD) exacerbations are a major cause of hospital admission and clinical guidelines for optimised management are available. However, few data assessing concordance with these guidelines are available. We aimed to identify gaps and document variability in clinical practices for COPD admissions. METHODS: Medical records of all admissions over a 3-month period as COPD with non-catastrophic or severe comorbidities or complications at eight acute-care hospitals within the Hunter New England region were retrospectively audited. RESULTS: Mean (SD) length of stay was 6.3 (6.1) days for 221 admissions with mean age of 71 (10), 53% female and 34% current smokers. Spirometry was performed in 34% of admissions with a wide inter-hospital range (4-58%, P < 0.0001): mean FEV1 was 36% (18) predicted. Arterial blood gases were performed on admission in 54% of cases (range 0-85%, P < 0.0001). Parenteral steroids were used in 82% of admissions, antibiotics in 87% and oxygen therapy during admission in 79% (with oxygen prescription in only 3% of these). Bronchodilator therapy was converted from nebuliser to an inhaler device in 51% of cases early in admission at 1.6 (1.7) days. Only 22% of patients were referred to pulmonary rehabilitation (inter-hospital range of 0-50%, P = 0.002). Re-admission within 28 days was higher in rural hospitals compared with metropolitan (27% vs 7%, P < 0.0001). CONCLUSIONS: We identified gaps in best practice service provision associated with wide inter-hospital variations, indicating disparity in access to services throughout the region.

First Report of Raffaelea canadensis Causing Laurel Wilt Disease Symptoms on Avocado in California.

Laurel wilt disease is a newly described vascular disease of redbay (Persea borbonia (L.) Spreng.) and other members of the Lauraceae family in the southeastern United States. The disease, caused by the fungus Raffaelea lauricola and vectored by a nonnative redbay ambrosia beetle (Xyleborus glabratus Eichhoff), was first detected in Georgia in 2003 (1). Laurel wilt has caused extensive mortality of native redbay in Georgia, Florida, South Carolina, and recently, Mississippi. The avocado, Persea americana, is in the Lauraceae family and has been shown to be susceptible to the laurel wilt pathogen in Florida (3). The potential spread of this pathogen into California is of concern to the commercial avocado industry. During a survey in 2010 in a Temecula, CA avocado orchard with a history of root rot, an avocado (cv. Hass) tree with a diameter at breast height (DBH) of 45 cm was found to be showing typical laurel wilt disease symptoms. The crown was approximately 80% declined and exhibited dead branches without leaves. Black-to-brown discolored sapwood under the bark and many ambrosia beetle exit holes within 1 to 1.5 m up the bole were also observed. A Raffaelea sp. was consistently isolated from symptomatic branch tissue (from two different branches) plated onto cycloheximide-streptomycin malt agar (2) and incubated at room temperature for 2 weeks. Small subunit (18S) sequences of rDNA (approximately 1,150 bp) of three Raffaelea isolates were amplified using primers NS1 and NS4 (4) and deposited into GenBank under Accession Nos. JF327799, JF327800, and JF327801. A BLASTn search of all three sequences revealed high homology (98, 99, and 98% respectively) to an accession of R. canadensis associated with a species of ambrosia beetle (GenBank Accession No. AY858665). Pathogenicity testing was conducted by pipetting 50 µl of a 105 conidia per ml suspension of each of two isolates (UCR1080 and UCR1081) into five 2-mm-diameter holes on each of two avocado (cv. Hass) trees (10 to 15 cm DBH). Isolate UCR1080 was inoculated into three holes on Tree 1 and two holes on Tree 2. Isolate UCR1081 was inoculated into two holes on Tree 1 and three holes on Tree 2. Sterile water was used as a control in five 2-mm-diameter holes on each tree. Holes were drilled to the cambium within 1 to 2 m up the bole using a 0.157-cm electric drill. Four months later, phloem tissue was peeled back, lesion lengths were measured, and pieces of necrotic tissue were cultured for completion of Koch's postulates. R. canadensis was consistently reisolated from necrotic tissue but not from control treatments. To our knowledge, this is the first report of R. canadensis associated with wilt on avocado in California. R. canadensis is closely related to R. lauricola, however, its impact on the California avocado industry is unknown at this time. References: (1) S. W. Fraedrich et al. Plant Dis. 92:215, 2008. (2) T. C. Harrington et al. Mycotaxon 111:337, 2010. (3) A. E. Mayfield et al. Plant Dis. 92:976, 2008. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

Prophylactic penicillin by the full moon: a novel approach in Central Australia that may help to reduce the risk of rheumatic heart disease.

INTRODUCTION: Uptake of penicillin prophylaxis to prevent recurrent rheumatic fever and its sequela rheumatic heart disease (RHD) is not optimal in the Northern Territory of Australia. The Full Moon Strategy (the Strategy) was introduced in the Central Australian region in June 2006 to improve the uptake of prophylactic penicillin: clients and healthcare workers were encouraged to use the full moon as a cue for the timing of the 4 weekly prophylactic penicillin injection. OBJECTIVE: To determine the impact and effectiveness of the Strategy on knowledge and uptake of benzathine penicillin prophylaxis for clients at risk of RHD, and for primary healthcare workers in Central Australia. METHODS: Clients at risk of RHD in four remote Aboriginal communities and the town camps of Alice Springs were identified from the RHD database. Consenting clients or their carers were interviewed about their knowledge of the Strategy and the health promotional tools used. Their healthcare records were then reviewed for prophylaxis uptake 2 years prior to and 2 years following the introduction of the Strategy. Primary healthcare workers in the four remote communities who were available at the time of the study visit were interviewed about their knowledge and use of the Strategy and the health promotional tools. RESULTS: Fifty RHD clients and 19 healthcare workers were interviewed. Most were aware of the flipchart but less than half knew of the calendar poster, hand-held card or radio advertisement. Prophylaxis uptake increased significantly from 47% in the 2 years prior to the introduction of the Strategy, to 57% 2 years after the Strategy was introduced. CONCLUSION: Introduction of the Strategy coincided with an improvement in uptake of prophylaxis but not around the time of the full moon. Uptake of benzathine penicillin remains inadequate and further innovative measures are needed to control rheumatic fever and its sequela in Aboriginal and Torres Strait Islander people.

Rituximab pharmacokinetics during the management of acute idiopathic thrombotic thrombocytopenic purpura.

BACKGROUND: Increasingly, patients with acute, idiopathic, antibody mediated thrombotic thrombocytopenic purpura (TTP) are being treated with rituximab to achieve a durable remission, however, there is the potential that it is removed by plasma exchange (PEX). OBJECTIVES: To look at the pharmacokinetics and pharmacodynamics of rituximab in patients with acute idiopathic TTP undergoing PEX. PATIENTS AND METHODS: Patients who received rituximab for acute idiopathic TTP (group 1, n = 30) and a control group (group 2, n = 3) of TTP patients in remission receiving rituximab electively as maintenance were included. Rituximab levels were measured before/after each infusion, before/after PEX and in follow-up. ADAMTS-13 activity, anti-ADAMTS-13 IgG and CD19% were measured to assess response. RESULTS: The median number of PEX to remission after rituximab was 10 (range 4-25). In group 1 there was no significant incremental rise in the peak serum rituximab level until dose 4. Trough levels were lower in patients who had had PEX since their last rituximab infusion. In the control group, there was an incremental rise in the peak serum rituximab level and all patients had detectable trough levels. The median fall in rituximab per PEX was 65%. All patients achieved CD19 < 1%. In group 1, the median time to undetectable rituximab was 5 months (range 0-12 months) and to B cell return was 7 months (range 3-24 months). ADAMTS-13 increased and anti-ADAMTS-13 fell after therapy. There were three deaths and two relapses in group 1. Relapse was not temporally related to B cell return.

Human leukocyte antigen association in idiopathic thrombotic thrombocytopenic purpura: evidence for an immunogenetic link.

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a rare, acute, life-threatening disorder, associated with a deficiency in ADAMTS 13. The majority of acute, idiopathic, adult TTP cases are associated with anti-ADAMTS 13 IgG antibodies. However, the factor(s) precipitating an acute TTP episode are not always obvious; indeed, a multifactorial etiology is likely. OBJECTIVES AND METHODS: DNA was used for human leukocyte antigen (HLA) class II typing, using polymerase chain reaction (PCR)-sequence-specific primer and PCR-sequence-specific oligonucleotide probe to methodology to investigate 50 European acquired idiopathic TTP cases. RESULTS: There was an increase in the frequency of HLA-DQB1*0301 (HLA-DQ7) in patients with TTP as compared with controls [58.0% vs. 34.5% (P=0.048)]. The frequencies of HLA-DRB1*11 and HLA-DRB3* were also significantly increased in TTP patients as compared with controls [44.0% vs. 12.0% (P=0.0024) and 84.0% vs. 58.0% (P=0.024)], although it remains uncertain whether susceptibility is influenced by HLA-DQ or HLA-DR molecules or other genes in this haplotype. The frequencies of HLA-DRB1*04 and HLA-DRB4 (HLA-DR53) were significantly decreased in the patient group as compared with controls [10.0% vs. 35.0% and 26.0% vs. 61.5% (P=0.0096 and P=0.0024, respectively)], and may have a protective effect against the development of TTP. CONCLUSION: Analysis identified HLA class II types associated with susceptibility to and a protective effect against the development of acute acquired TTP in European patients. This provides the first description of a genetic factor predicting the risk of developing acquired antibody-mediated TTP.

Past and future: vaccination against Eimeria.

Eimeria spp. are the causative agents of coccidiosis, a major disease affecting many intensively-reared livestock, especially poultry. The chicken is host to 7 species of Eimeria that develop within intestinal epithelial cells and produce varying degrees of morbidity and mortality. Control of coccidiosis by the poultry industry is dominated by prophylactic chemotherapy but drug resistance is a serious problem. Strongly protective but species-specific immunity can be induced in chickens by infection with any of the Eimeria spp. At the Institute of Animal Health in Houghton, UK in the 1980s we showed that all 7 Eimeria spp. could be stably attenuated by serial passage in chickens of the earliest oocysts produced (i.e. the first parasites to complete their endogenous development) and this process resulted in the depletion of asexual development. Despite being highly attenuated, the precocious lines retained their immunizing capacity. Subsequent work led to the commercial introduction of the first live attenuated vaccine, Paracox, that has now been in use for 20 years. As much work still remains to be done before the development of recombinant vaccines becomes a reality, it is likely that reliance upon live, attenuated vaccines will increase in years to come.

Steady-state migrating intestinal dendritic cells induce potent inflammatory responses in naive CD4+ T cells.

Steady-state dendritic cells (DCs) migrating in the lymph from the intestine induce tolerance to harmless intestinal antigens, preventing inflammatory responses. To determine if such DCs are inherently tolerogenic we collected intestinal lymph DCs (L-DCs) by cannulation of the thoracic duct of rats after mesenteric lymphadenectomy, and examined their capacity to activate naive CD4+ lymphocytes in an allogeneic mixed leucocyte reaction. L-DCs stimulated strong proliferative responses, induced secretion of inflammatory cytokines including interferon-gamma, and induced FoxP3-positive lymphocytes to divide. To determine if the activated CD4+ T cells had been tolerized, they were rested and restimulated with irradiated splenocytes. The restimulated CD4+ T cells again proliferated and secreted inflammatory cytokines. These data demonstrate that the DCs, which migrate from the intestine in the steady state, are paradoxically able to induce strong inflammatory responses from naive T cells, despite their role in the maintenance of oral tolerance.

Interferon-gamma-mediated activation of enterocytes in immunological control of Encephalitozoon intestinalis infection.

The microsporidian Encephalitozoon intestinalis develops within intestinal epithelial cells (enterocytes) and is an important opportunistic diarrhoeal pathogen associated with AIDS. Little is known about the protective immune response against the parasite although in mice IFN-gamma is involved and is required to prevent dissemination of the infection to other organs. The present study was designed to establish a suitable short-term in vitro culture technique for E. intestinalis that would enable studies of the role of cytokines such as IFN-gamma in the effector phase of immunity. Encephalitozoon intestinalis reproduced considerably better in the murine enterocyte cell line CMT-93 than in the three human enterocyte cell lines Caco-2, HT29 and HCT-8. Treatment of CMT-93 cells with IFN-gamma significantly reduced parasite reproduction in a dose- and time-dependent manner. IFN-gamma also inhibited development of the parasite in Caco-2 cells. Neither production of NO nor Fe deprivation appeared to be involved in IFN-gamma-mediated parasite killing. However studies suggested that tryptophan catabolism by indoleamine 2,3-dioxygenase played an important part in inactivation of E. intestinalis.

Thrombotic thrombocytopenic purpura precipitated by acute pancreatitis: a report of seven cases from a regional UK TTP registry.

Thrombotic thrombocytopenic purpura (TTP) may be idiopathic or secondary. We report seven TTP cases precipitated by pancreatitis. The patients were admitted with acute pancreatitis and at that time had no clinical or laboratory features of TTP. The median time to develop TTP after pancreatitis was 3 d. The patients had moderately reduced ADAMTS13 activity (mean activity 49%; normal range 66-126%) with no evidence of anti-ADAMTS13 inhibitory autoantibodies. The median number of plasma exchanges to remission was 10 (range 7-14) and no additional treatment with immunosuppression was required to maintain remission. There have been no relapses to date.