Mamidipudi T. Krishna

Diagnosis and management of hymenoptera venom allergy: British Society for Allergy and Clinical Immunology (BSACI) guidelines

This guidance for the management of patients with hymenoptera venom allergy has been prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI). The guideline is based on evidence as well as on expert opinion and is for use by both adult physicians and pediatricians practising allergy. During the development of these guidelines, all BSACI members were included in the consultation process using a web‐based system. Their comments and suggestions were carefully considered by the SOCC. Where evidence was lacking, consensus was reached by the experts on the committee. Included in this guideline are epidemiology, risk factors, clinical features, diagnostic tests, natural history of hymenoptera venom allergy and guidance on undertaking venom immunotherapy (VIT). There are also separate sections on children, elevated baseline tryptase and mastocytosis and mechanisms underlying VIT. Finally, we have made recommendations for potential areas of future research.

Diagnostic role of tests for T cell receptor (TCR) genes.

Rapid advances in molecular biological techniques have made it possible to study disease pathogenesis at a genomic level. T cell receptor (TCR) gene rearrangement is an important event in T cell ontogeny that enables T cells to recognise antigens specifically, and any dysregulation in this complex yet highly regulated process may result in disease. Using techniques such as Southern blot hybridisation, polymerase chain reaction, and flow cytometry it has been possible to characterise T cell proliferations in malignancy and in diseases where T cells have been implicated in the pathogenesis. The main aim of this article is to discuss briefly the process of TCR gene rearrangement and highlight the disorders in which expansions or clonal proliferations of T cells have been recognised. It will also describe various methods that are currently used to study T cell populations in body fluids and tissue, their diagnostic role, and current limitations of the methodology.

Management of allergy to penicillins and other beta‐lactams

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non‐immediate allergic reactions to penicillins and other beta‐lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web‐based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta‐lactams, molecular structure, formulations available in the UK and a description of known beta‐lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross‐reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta‐lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

The United Kingdom Primary Immune Deficiency (UKPID) Registry: report of the first 4 years' activity 2008-2012

This report summarizes the establishment of the first national online registry of primary immune deficency in the United Kingdom, the United Kingdom Primary Immunodeficiency (UKPID Registry). This UKPID Registry is based on the European Society for Immune Deficiency (ESID) registry platform, hosted on servers at the Royal Free site of University College, London. It is accessible to users through the website of the United Kingdom Primary Immunodeficiency Network (www.ukpin.org.uk). Twenty‐seven centres in the United Kingdom are actively contributing data, with an additional nine centres completing their ethical and governance approvals to participate. This indicates that 36 of 38 (95%) of recognized centres in the United Kingdom have engaged with this project. To date, 2229 patients have been enrolled, with a notable increasing rate of recruitment in the past 12 months. Data are presented on the range of diagnoses recorded, estimated minimum disease prevalence, geographical distribution of patients across the United Kingdom, age at presentation, diagnostic delay, treatment modalities used and evidence of their monitoring and effectiveness.

Multi-centre retrospective analysis of anaphylaxis during general anaesthesia in the United Kingdom: aetiology and diagnostic performance of acute serum tryptase

This is the first multi‐centre retrospective survey from the United Kingdom to evaluate the aetiology and diagnostic performance of tryptase in anaphylaxis during general anaesthesia (GA). Data were collected retrospectively (2005–12) from 161 patients [mean ± standard deviation (s.d.), 50 ± 15 years] referred to four regional UK centres. Receiver operating characteristic curves (ROC) were constructed to assess the utility of tryptase measurements in the diagnosis of immunoglobulin (Ig)E‐mediated anaphylaxis and the performance of percentage change from baseline [percentage change (PC)] and absolute tryptase (AT) quantitation. An IgE‐mediated cause was identified in 103 patients (64%); neuromuscular blocking agents (NMBA) constituted the leading cause (38%) followed by antibiotics (8%), patent blue dye (6%), chlorhexidine (5%) and other agents (7%). In contrast to previous reports, latex‐induced anaphylaxis was rare (0·6%). A non‐IgE‐mediated cause was attributed in 10 patients (6%) and no cause could be established in 48 cases (30%). Three serial tryptase measurements were available in 34% of patients and a ROC analysis of area under the curve (AUC) showed comparable performance for PC and AT. A ≥ 80% PPV for identifying an IgE‐mediated anaphylaxis was achieved with a PC of >141% or an AT of >15·7 mg/l. NMBAs were the leading cause of anaphylaxis, followed by antibiotics, with latex allergy being uncommon. Chlorhexidine and patent blue dye are emerging important health‐care‐associated allergens that may lead to anaphylaxis. An elevated acute serum tryptase (PC >141%, AT >15·7 mg/l) is highly predictive of IgE‐mediated anaphylaxis, and both methods of interpretation are comparable.

Compromised concentrations of ascorbate in fluid lining the respiratory tract in human subjects after exposure to ozone.

OBJECTIVES: Ozone (O3) imposes an oxidative burden on the lung in two ways. Firstly, directly as a consequence of its oxidising character during exposure, and secondly, indirectly by engendering inflammation. In this study the second pathway was considered by ascertaining the impact of O3 on the redox state of the fluid lining the respiratory tract 6 hours after challenge. METHODS: Nine subjects were exposed in a double blind crossover control trial to air and 200 ppb O3 for 2 hours with an intermittent exercise and rest protocol. Blood samples were obtained and lung function (forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1)) assessed before, immediately after, and 6 hours after exposure. Bronchoalveolar lavage (BAL) was performed 6 hours after challenge. Inflammation was assessed in BAL fluid (total and differential cell counts, plus myeloperoxidase concentrations), and plasma and BAL fluid redox state were determined by measuring concentrations of antioxidants and markers of oxidative damage. RESULTS: Neutrophil numbers in BAL fluid increased 2.2-fold (p = 0.07) 6 hours after exposure and this was accompanied by increased myeloperoxidase concentrations in BAL fluid (p = 0.08). On the other hand, BAL fluid macrophage and lymphocyte numbers decreased 2.5-fold (p = 0.08) and 3.1-fold (p = 0.08), respectively at this time. Of the antioxidants examined, only ascorbate in BAL fluid was affected by O3, falling in all subjects relative to air values (0.1 (0.0-0.3) v 0.3 (0.2-1.2) mumol/l (p = 0.008)). A marginal decrease in plasma ascorbate was also detected at this time (p < 0.05). Although the decrease in macrophage numbers seemed to be causally related to the increase in neutrophils (R = -0.79), myeloperoxidase concentrations (R = -0.93) and ascorbate concentrations (R = 0.6), no clear associations were apparent between ascorbate changes and neutrophils or myeloperoxidase concentration after O3. CONCLUSIONS: Ascorbate in the fluid lining the respiratory tract is depleted as a consequence of O3 exposure at 6 hours after exposure. This was contemporaneous with, although not quantitatively related to the increase in neutrophil numbers and myeloperoxidase concentrations. Decreased macrophage numbers 6 hours after O3 related to the degree of neutrophilic inflammation with populations conserved where ascorbate concentration in the fluid lining the respiratory tract were high after exposure. These results imply that ascorbate has a critical protective role against inflammatory oxidative stress induced by O3.

Does rituximab aggravate pre-existing hypogammaglobulinaemia?

Rituximab, an anti-CD20 chimeric antibody, is the first monoclonal agent to be used in the therapy of cancer. It has been hailed as one of the most important therapeutic developments of the decade. While transient peripheral B cell depletion is common after rituximab therapy, immunoglobulin levels are generally not affected. This is because CD20 is expressed on pre-B and mature B lymphocytes but not on stem cells or plasma cells. Two adult patients with pre-existing primary antibody deficiency who presented with recurrent infections immediately following rituximab use for the treatment of refractory idiopathic thrombocytopenic purpura (ITP) are described. Both were previously treated with various immunosuppressive agents without any notable infective problems. However, a few weeks after treatment with rituximab, these patients presented with clinically significant immunodeficiency requiring intravenous immunoglobulin replacement therapy. This striking temporal relationship between rituximab administration and onset of infections suggests that rituximab has accelerated the presentation of immune deficiency in these patients. Increased vigilance around the use of newer immunomodulatory agents such as rituximab is recommended.

Repeated daily exposure to 2 ppm nitrogen dioxide upregulates the expression of IL-5, IL-10, IL-13, and ICAM-1 in the bronchial epithelium of healthy human airways

Background: Repeated daily exposure of healthy human subjects to NO2 induces an acute airway inflammatory response characterised by neutrophil influx in the bronchial mucosa Aims: To assess the expression of NF-κB, cytokines, and ICAM-1 in the bronchial epithelium. Methods: Twelve healthy, young non-smoking volunteers were exposed to 2 ppm of NO2/filtered air (four hours/day) for four successive days on separate occasions. Fibreoptic bronchoscopy was performed one hour after air and final NO2 exposures. Bronchial biopsy specimens were immunostained for NF-κB, TNF-α, eotaxin, Gro-α, GM-CSF, IL-5, -6, -8, -10, -13, and ICAM-1 and their expression was quantified using computerised image analysis. Results: Expression of IL-5, IL-10, IL-13, and ICAM-1 increased following NO2 exposure. Conclusion: Upregulation of the Th2 cytokines suggests that repeated exposure to NO2 has the potential to exert a “pro-allergic” effect on the bronchial epithelium. Upregulation of ICAM-1 highlights an underlying mechanism for leucocyte influx, and could also explain the predisposition to respiratory tract viral infections following NO2 exposure since ICAM-1 is a major receptor for rhino and respiratory syncytial viruses.

A real-time prospective evaluation of clinical pharmaco-economic impact of diagnostic label of ‘penicillin allergy’ in a UK teaching hospital

Aims To perform a pharmaco-economic analysis of prescribing alternative antibiotics in patients with a diagnostic label of ‘penicillin allergy’ and assess whether collation of information from a structured history and liaison with the family physician could reduce costs. Methods A prospective pro-forma-based interview of randomly selected in-patients and their family physician was used to assess the validity of the diagnostic label of ‘penicillin allergy’. Cost analysis of prescription of alternative antibiotics was performed and compared with first-line agents. Results 102 patients were assessed and only 40% (n=41) were found to have a history consistent with penicillin hypersensitivity, 40% (n=41) were likely ‘not allergic’ and 20% (n=20) had ‘indeterminate’ reactions. Total cost of antibiotics prescribed for patients with penicillin allergy was 1.82–2.58-fold higher than for first-line antibiotics. Conclusions Obtaining a structured history from the patient and family physician alone can enable an accurate identification of penicillin allergy status. Total acquisition cost of second-line antibiotics is higher than if these patients were prescribed first-line antibiotics.

Risk factors for systemic reactions to bee venom in British beekeepers

BACKGROUND There is a high incidence of systemic reactions (SRs) to bee stings in beekeepers, but the factors predisposing individuals to such responses are not well understood. OBJECTIVES To identify factors that predispose British beekeepers to SRs and to investigate how beekeepers access specialist services after SRs to bee venom. METHODS A link to an online survey was published in the bimonthly magazine and on the Web site of the British Beekeepers Association. The demographic results are presented using descriptive analysis, and a logistic regression model was used to determine risk factors for SRs. RESULTS There were 852 responses to the questionnaire of which 63% were from male beekeepers; the most common age range was 51 to 60 years. Twenty-eight percent of all responders had experienced a large local reaction and 21% had experienced a SR. Factors that predisposed beekeepers to SRs included female sex, having a family member with bee venom allergy, more than 2 years of beekeeping before a SR, and premedication with an antihistamine before attending the hives. A total of 44% of beekeepers with SRs attended the emergency department because of their symptoms, 16.6% were reviewed by an allergy specialist, and only 18% carried an adrenaline autoinjector. CONCLUSIONS Logistic regression analysis identified a number of novel factors to be associated with the development of SRs. Rates of attendance at the emergency department, allergy specialist review, and carriage of adrenaline were low, highlighting a need for education in the beekeeping community and among health care professionals.