American Academy of Allergy, Asthma & Immunology Work Group Report: allergy diagnosis in clinical practice

Comparison of commercial allergen extract with various milk products of skin prick tests in diagnosing cow's milk protein allergy

Introduction: In this study, we aimed to solve the incompatibilities between the skin prick test (SPT) result and the clinical picture encountered among patients. Thus, we used various milk products (raw, ultrahigh temperature [UHT], and pasteurized cow's milk) with commercial milk allergen extract in patients we think may have cow's milk protein allergy (CMPA) and made a comparison among the milk types. Methods: This study was conducted retrospectively between February 1, 2019, to June 1, 2019, at a pediatric allergy polyclinic of the university training/research hospital. A pair of 79 individuals, as control and patient groups, ages between 1 month and 21 years who were presented with a suspicion of CMPA and defined with SPT and/or allergen-specific immunoglobulin E (IgE) levels were included in the study. Allergen-specific IgE tests (specific IgE cow's milk, β-lactoglobulin, α-lactalbumin, casein) were evaluated. SPT was performed with fresh/raw, UHT, and pasteurized (daily) cow's milk besides the standard used commercial extract. Results: In the group included in the study and defined as IgE-mediated CMPA, 52.9% of the 79 patients were boys (n = 46), 47.1% were girls (n = 33), and the median age was 6 months (5.0-8.0 months). In the group of specific IgE cow's milk reaction that was sought, frequency and wheal (induration) size of SPT reaction to fresh/raw milk was also found to be statistically significant between positive- and negative-reaction groups, not detected against other milk products. The area under the curve for the diagnostic value of fresh milk was 93.1%. For the cutoff value of 2.50 mm, 88.1% sensitivity and 90.8% specificity were determined. In the group of specific IgE β-lactoglobulin reaction searched, there was a statistically significant difference in the frequency of SPT positivity and wheal size against UHT, fresh, and daily/pasteurized milk between positive and negative reaction groups. When the correlations of the mean induration axis in the tests were examined, it was found that, among raw milk, daily milk, cow's milk allergen extract, and UHT milk, a strong positive correlation was also statistically significant. Conclusion: The positivity that could not be detected with SPT when using allergen extract in a patient with positive specific IgE cow's milk result in the clinic can be detected with SPT made with fresh (raw) milk, which can be an alternative. In addition, specific IgE β-lactoglobulin seems to be the most compatible with the SPT wheal size (induration) of other milk types rather than extract. Comparative studies of SPT allergen extracts and various milk types used in the diagnosis of CMPA are very scarce in the literature, and more studies are needed on this subject.

Arginase Isoform Expression in Chronic Rhinosinusitis

Nitric oxide (NO) has emerged as an important regulator of upper airway inflammation, mainly as part of the local naso-sinusal defense mechanisms. Increased arginase activity can reduce NO levels by decreasing the availability of its precursor, L-arginine. Chronic rhinosinusitis (CRS) has been associated with low levels of nasal nitric oxide (nNO). Thus, the present study investigates the activity of arginase I (ARG1) and II (ARG2) in CRS and its possible involvement in the pathogenesis of this disease. Under endoscopic view, tissue samples of pathologic (n = 36) and normal (n = 29) rhinosinusal mucosa were collected. Arginase I and II mRNA levels were measured using real-time PCR. Our results showed low arginase I activity in all samples. The levels of ARG2 were significantly higher in patients with chronic rhinosinusitis compared to the control group (fold regulation (FR) 2.22 ± 0.42 vs. 1.31 ± 0.21, p = 0.016). Increased ARG2 expression was found in patients with CRS without nasal polyposis (FR 3.14 ± 1.16 vs. 1.31 ± 0.21, p = 0.0175), in non-allergic CRS (FR 2.55 ± 0.52 vs. 1.31 ± 0.21, p = 0.005), and non-asthmatic CRS (FR 2.42 ± 0.57 vs. 1.31 ± 0.21, p = 0.028). These findings suggest that the upregulation of ARG2 may play a role in the pathology of a distinctive phenotype of CRS.

Evaluation of 563 children with chronic cough accompanied by a new clinical algorithm

BACKGROUND

This study aims to evaluate the children with chronic cough and to analyze their etiological factors according to the age groups.

METHOD

Five hundred sixty-three children with chronic cough were included. The last diagnosis were established and were also emphasized according to the age groups.

RESULTS

The mean age was 5.4 ± 3.8 years (2-months-17-years) and 52 % of them were male. The most common final diagnosis from all the participants were: asthma (24.9 %), asthma-like symptoms (19 %), protracted bacterial bronchitis (PBB) (11.9 %), and upper airway cough syndrome (9.1 %). However, psychogenic cough was the second most common diagnosis in the subjects over 6 years of age.

CONCLUSION

Asthma and asthma-like symptoms were the most common diagnosis in children. Different age groups in children may have a different order of frequencies. Psychogenic cough should be thought of in the common causes especially in older children.

Assessment of allergen-induced respiratory hyperresponsiveness before the prescription of a specific immunotherapy

BACKGROUND

Asymptomatic sensitization is a frequent condition that must be considered before the indication of allergic-specific immunotherapy.

OBJECTIVE

The aim of this study was to appreciate and correlate the local and spirometric changes elicited by the allergen-specific nasal provocation test (NPT) to define practical and feasible guidelines for the allergist/immunologist to demonstrate specific respiratory hyperresponsiveness before the indication of allergic-specific immunotherapy.

METHODS

A total of 172 subjects (children and adults) with a diagnosis of allergic rhinitis were submitted to flow-volume spirometry immediately before and after the NPT performed with Dermatophagoides antigens. The differences between the pre- and postspirometric estimated values of peak expiratory flow rate (PEFdif%), forced expiratory volume in 1 second (FEV1dif%), and forced vital capacity (FVCdif%) were correlated with the results of the nasal provocation test symptom score (NPT-SS).

RESULTS

There were 119 subjects (69%) with NPT-SS > 2. Among these patients who were reactive, the mean NPT-SS was 6.3. The Spearman's correlation between PEFdif% and NPT-SS was r = -0.44 (p = 0.01); the Spearman's correlation between FEV1dif% and NPT-SS was r = -0.22 (p = 0.01), and the Spearman's correlation between FVCdif% and NPT-SS was r = -0.21 (p = 0.04).

CONCLUSION

The combined utilization of the allergen-specific NPT-SS with the spirometry (or PEF meter) is a safe methodology to evaluate allergen-specific nasal and bronchial hyperresponsiveness (which sometimes acts as a bronchial provocation test) in patients with allergic rhinitis and asthma due to hypersensitivity who are candidates for allergen-specific immunotherapy.

Allergy Diagnosis in Children and Adults: Performance of a New Point-of-Care Device, ImmunoCAP Rapid

BACKGROUND

: Allergy is a serious problem affecting approximately 1 of 4 individuals. The symptoms with and without allergy etiology are often difficult to distinguish from each other without using an IgE antibody test. The aim of this study was to investigate the performance of a new point-of-care (POC) test for IgE antibodies to relevant allergens in Europe.

METHODS

: IgE antibodies from children and adults with allergies recruited from allergy clinics in Sweden and Spain were analyzed for 10 allergens, suitable for the age groups, using the new POC test and ImmunoCAP laboratory test. The IgE antibody level best discriminating between positive and negative results (the cutoff point) for the different allergens of the POC test and the efficacy of the POC and the ImmunoCAP laboratory tests for diagnosing allergy compared with that of clinical diagnosis were investigated.

RESULTS

: The estimated cutoffs for the different allergens in the POC test ranged from 0.70 to 2.56 kUA/L. Taking into account all positive allergen results in a given patient, the POC test could identify 95% of the patients with allergies. Seventy-eight percent of the allergen-specific physicians' diagnoses were identified and 97% of the negative ones. Most allergens exhibited good performance, identifying about 80% of clinically relevant cases. However, dog, mugwort, and wall pellitory would benefit from improvement.

CONCLUSIONS

: The POC test will be a valuable adjunct in the identification or exclusion of patients with allergies and their most likely offending allergens, both in specialist and general care settings.

Diagnostic tests for human allergic disease

BACKGROUND

The diagnosis of human allergic disease begins with a thorough clinical history and physical examination. Once a temporal relationship has been identified between a patient's history of allergic symptoms and a defined allergen exposure, confirmatory analyses for IgE antibody involving skin or blood testing are performed to verify sensitization. Debate continues over the relative diagnostic utility of the in vivo and in vitro measures of IgE antibody.

OBJECTIVE

This overview examines the strengths and limitations of primary diagnostic confirmatory methods for in vivo detection (skin test, provocation test) and in vitro quantification of IgE antibody.

METHODS

A literature review was performed to examine diagnostic performance characteristics and variables that influence the accuracy of IgE antibody assays.

DISCUSSION

The clinical history and both in vivo and in vitro measures of IgE antibody are subject to variability and potential patient, clinician and technician-related bias. As such, in the absence of an absolute clinical history-based gold standard for defining the presence of allergic disease, the relative diagnostic performance (sensitivity, specificity) of in vivo versus in vitro assays of IgE antibody cannot be effectively determined. The review examines which allergic disease states and allergen specificities allow both groups of IgE antibody assays to produce comparable qualitative data for assessing the state of allergic sensitization. Skin testing has experienced few recent technological innovations, whereas an explosion has occurred in the improved performance (analytical sensitivity and specificity) of in vitro assays and enhanced quality of reagents for IgE antibody quantification. This review discusses the impact of point of care-testing assays, microarrays, the use of native and recombinant allergen molecules, automation, and disease prediction algorithms and the 2008 Clinical and Laboratory Standards Institute Guideline on IgE antibody methods, on the diagnosis of human allergic disease.