Sally Kilburn

An evaluation of the sensitivity of subjects with peanut allergy to very low doses of peanut protein: A randomized, double-blind, placebo-controlled food challenge study☆☆☆★

BACKGROUND The minimum dose of food protein to which subjects with food allergy have reacted in double-blind, placebo-controlled food challenges is between 50 and 100 mg. However, subjects with peanut allergy often report severe reactions after minimal contact with peanuts, even through intact skin. OBJECTIVE We sought to determine whether adults previously proven by challenge to be allergic to peanut react to very low doses of peanut protein. METHODS We used a randomized, double-blind, placebo-controlled food challenge of 14 subjects allergic to peanuts with doses of peanut ranging from 10 microg to 50 mg, administered in the form of a commercially available peanut flour. RESULTS One subject had a systemic reaction to 5 mg of peanut protein, and two subjects had mild objective reactions to 2 mg and 50 mg of peanut protein, respectively. Five subjects had mild subjective reactions (1 to 5 mg and 4 to 50 mg). All subjects with convincing objective reactions had short-lived subjective reactions to preceding doses, as low as 100 microg in two cases. Five subjects did not react to any dose up to 50 mg. CONCLUSION Even in a group of well-characterized, highly sensitive subjects with peanut allergy, the threshold dose of peanut protein varies. As little as 100 microg of peanut protein provokes symptoms in some subjects with peanut allergy.

Clinical characteristics of peanut allergy

Background Current clinical advice regarding peanut allergy is based on small series of patients.

Does severity of low‐dose, double‐blind, placebo‐controlled food challenges reflect severity of allergic reactions to peanut in the community?

Background The severity of allergic reactions to food appears to be affected by many interacting factors. It is uncertain whether challenge‐based reactions reflect the severity of past reactions or can predict future risk.

Serological characteristics of peanut allergy

Peanut is the most common cause of severe or fatal food‐associated anaphylaxis. Studies indicate that peanut extracts contain many allergenic proteins. The identification of major and minor allergenic components is necessary for standardization of experimental and diagnostic extracts.

Breast cancer follow up: a randomised controlled trial comparing point of need access versus routine 6-monthly clinical review.

AIM To examine a model of care for breast cancer patients based on the concept of point of need access and investigate the effectiveness of this model compared to routine 6-monthly clinical reviews. DESIGN A parallel randomised controlled trial was used to examine point of need access to specialist care via the nurse specialist, compared to routine hospital based 6-monthly clinical review at year two post breast cancer diagnosis. A total of 237 patients were recruited to the study. METHODS Outcome measures at baseline, 9 and 18 months included psychological morbidity using the GHQ12 questionnaire, quality of life using the FACT-B plus endocrine subscale, fear and isolation. An analysis of covariance was used to detect changes over time. Recurrences and methods of detection were recorded as secondary outcome measures. RESULTS Two hundred and fourteen patients completed the study. Overall patients were not exposed to risks of increased psychological morbidity (p=0.767) or decline of quality of life (p=0.282) when routine review was discontinued and no significant differences were detected during an 18-month period. Patients not receiving regular review did not feel isolated, and at the end of 18 months did not wish to return to 6-monthly clinical reviews. The presentation of recurrences and short symptom history demonstrate that the recurrences observed were unlikely to have been detected at a routine visit. CONCLUSIONS Point of need access is acceptable to the majority of patients. Although a third of patients may wish to maintain a regular review, patient choice is important. Findings suggest that after 2 years following the diagnosis of breast cancer there is no evidence to support the view that regular clinical review improves psychological morbidity or quality of life. Patients do not appear to be compromised in terms of early detection of recurrence. Point of need access can be provided by suitably trained specialist nurses and provides a fast, responsive management system at a time when patients really need it.

Pre-natal sensitization in humans

Allergy has a very strong hereditary component but even in identical twins, concordance for the development of allergic disease can be as low as 50%. This suggests that there is a very strong environmental influence on manifestations of sensitization. To what extent environment might have an influence on the ontogeny of sensitization antenatally has hitherto not been a focus of much research. However, circumstantial evidence suggests that this may be important.

A critical assessment of two real-time PCR assays targeting the (SSU) rRNA and gdh genes for the molecular identification of Giardia intestinalis in a clinical laboratory.

Introduction Giardiasis is an intestinal diarrhoeal illness caused by the flagellate protozoan parasite Giardia intestinalis. Molecular techniques for the identification of G. intestinalis have generally been shown to offer a better detection rate of the parasite than the traditional faecal concentration and microscopy techniques. Aim The aim of this study was to critically assess the performance of a commercial and a published real-time PCR assay for their potential use as frontline tests for the diagnosis of giardiasis. Methods A composite reference standard of enzyme immunoassay and rapid membrane test was used in a diagnostic accuracy study to assess the performance of Primerdesigns, and Verweij et al G. intestinalis real-time PCR assays, comparing them with the traditional ova, cysts and parasite microscopy test (OCP-M). Results The Verweij real-time PCR used primers for the (SSU) rRNA gene, and produced a diagnostic sensitivity of 93.4% (95% CI 88.30% to 98.50%) and an efficiency of 100%. Primerdesigns real-time PCR used primers for the glutamate dehydrogenase gene and produced a diagnostic sensitivity of 61.5% (95% CI 51.50% to 71.50%) and an efficiency of 203%. The OCP-M sensitivity was 83.5% (95% CI 75.87% to 91.13%). Conclusions The Verweij real-time PCR was robust and the most sensitive assay suited for use as a first-line diagnostic test for giardiasis.

Prevalence Of Fish and Shellfish Allergy- A Systematic Review

BACKGROUND Accurate information on the prevalence of food allergy facilitates a more evidence-based approach to planning of allergy services and can identify important geographic variations. OBJECTIVE To conduct a systematic review to assess the age-specific prevalence of fish and shellfish allergy worldwide. METHODS Searches were conducted using Web of Science and PubMed. Population-based cross-sectional studies and cohort studies that examined the prevalence of fish and shellfish allergy (IgE mediated and non-IgE mediated) at an identifiable point in time were eligible for inclusion in the study. Reviewers extracted general study information and study design, type of food allergy considered, food(s) assessed, method of diagnosis, sampling strategy, and sample characteristics. Raw data were extracted and percentage prevalence and 95% confidence intervals calculated. RESULTS A total of 7,333 articles were identified of which 61 studies met the inclusion criteria and were included in this review. The prevalence of fish allergy ranged from 0% to 7% and the prevalence of shellfish allergy from 0% to 10.3%, depending on the method of diagnosis. Where food challenges were used, the prevalence for fish allergy was found to be 0% to 0.3% and for shellfish allergy was 0% to 0.9%. CONCLUSION Few studies have established the prevalence of fish or shellfish allergy using the gold standard double-blind, placebo-controlled challenge criteria, with most instead relying on self-reported questionnaire-based methods. The limited data available suggest that fish allergy prevalence is similar worldwide; however, shellfish allergy prevalence may be higher in the Southeast Asia region.

Validation of the sperm class analyser CASA system for sperm counting in a busy diagnostic semen analysis laboratory.

Abstract Sperm counts have been linked to several fertility outcomes making them an essential parameter of semen analysis. It has become increasingly recognised that Computer-Assisted Semen Analysis (CASA) provides improved precision over manual methods but that systems are seldom validated robustly for use. The objective of this study was to gather the evidence to validate or reject the Sperm Class Analyser (SCA) as a tool for routine sperm counting in a busy laboratory setting. The criteria examined were comparison with the Improved Neubauer and Leja 20-μm chambers, within and between field precision, sperm concentration linearity from a stock diluted in semen and media, accuracy against internal and external quality material, assessment of uneven flow effects and a receiver operating characteristic (ROC) analysis to predict fertility in comparison with the Neubauer method. This work demonstrates that SCA CASA technology is not a standalone ‘black box’, but rather a tool for well-trained staff that allows rapid, high-number sperm counting providing errors are identified and corrected. The system will produce accurate, linear, precise results, with less analytical variance than manual methods that correlate well against the Improved Neubauer chamber. The system provides superior predictive potential for diagnosing fertility problems.

Allergens in mother's milk: Tolerisation or sensitization

The perinatal period has been described as a window of increased susceptibility for allergic sensitization. Avoidance of allergenic proteins by extended breast feeding and delayed onset of weaning is generally agreed to be beneficial. Case reports indicate however that dietary proteins may be transferred to the mothers milk and cause atopic symptoms. This study looked at the effect of a maternal allergen exclusion diet during lactation alone on the development of atopy in infants with a similar weaning regimen. Families were recruited when one or both parents was atopic. The maternal exclusion diet group (n=15) and the normal diet group (n=96) were self selected. Infants were assessed at 3,6,12 and 18 months and skin prick tests performed at 6,12 and 18 months. Eczema and eczema associated with food sensitivity tended to be more frequent in the maternal diet group, although the differences did not reach statistical significance. Despite the advice that infants should not be given egg before 12 months of age 40% of the infants with eczema had positive skin prick test results to egg at 6 months and 33% at 12 months. In the whole study group the frequency of food associated eczema was higher in first born infants (p=0.04) at 6 months of age. This pilot study indicates that maternal elimination diet during lactation alone is not beneficial. This may be due to the importance of genetic factors, in utero sensitization or post birth sensitization through inhalation or ingestion.