Evaluation of the phadiatop test in the diagnosis of allergic sensitization in a general adult population

BACKGROUND

Phadiatop is a commercially available qualitative serological test employed for screening of allergic sensitization in patients with suspected allergic diseases.

AIM

The study evaluated the diagnostic accuracy of Phadiatop for the diagnosis of allergic sensitization in a general adult population.

METHODS

A total of 469 subjects from the population of A-Estrada (Spain) were selected by age-stratified random sampling (age range, 18-92 years). Phadiatop test (Uni-CAP method) was performed in serum samples from 465 of these subjects. Skin prick tests to a panel of 13 relevant aeroallergens in the studied area (including mites, pollens, moulds, and animal dander) were employed as the reference diagnostic procedure. Subjects with at least a positive skin prick test (> or =4 mm, n= 120) were considered to have allergic sensitization.

RESULTS

Phadiatop sensitivity was 70.8% (95% CI 61.7-78.6%), specificity 90.7% (95% CI 87.0-93.5%), positive predictive value 72.6% (95% CI 63.5-80.3%), negative predictive value 89.9% (95% CI 86.2-92.8%), global accuracy 85.6% (95% CI 82.0-88.6%), negative likelihood ratio 0.3 (95% CI 0.2-0.4), and positive likelihood ratio 7.6 (95% CI 5.4-10.8). A high proportion of false-positive Phadiatop cases showed (a) increased total serum IgE levels, (b) significant alcohol consumption, and (c) small-sized (below the diagnostic cut-off) wheal reactions on SPT. A high proportion of false-negative Phadiatop cases showed exclusive storage mite sensitization. Sensitivity and positive predictive value of Phadiatop were somewhat higher among individuals with a history of nasal or bronchial symptoms.

CONCLUSIONS

Phadiatop is a valuable tool for the diagnosis of allergic sensitization in a general adult population. However, limitations of the test should be taken into account in similar surveys.

Association of hepatitis A virus infection with allergic sensitization in a population with high prevalence of hepatitis A virus exposure

BACKGROUND

An inverse association between allergic sensitization and markers of exposure to food-borne and orofecal infections (particularly hepatitis A virus, HAV) has been reported. The prevalence of HAV exposure and allergic sensitization vary widely in different areas, and vary along with age within a given area.

AIM

To investigate the association between HAV exposure and allergic sensitization in adults from a mostly rural area of Spain.

METHODS

An age-stratified random sample of 720 subjects was drawn from the population older than 18 years of A-Estrada, Spain. From 697 eligible subjects, 469 (67.2%, median age 54 years, range: 18-92) participated in the study. Positive skin prick tests to a panel of aeroallergens defined allergic sensitization. Positive serum HAV antibodies (assayed in 465 subjects) defined HAV exposure.

RESULTS

The prevalence of HAV exposure was 83.6% (95% CI: 80.7-86.5). The prevalence of allergic sensitization was lower in subjects with HAV exposure than in patients without it (25.0%vs 40.0%, OR 0.44, 95% CI: 0.25-0.77, P=0.004), but this association became substantially altered after adjusting for age, which was closely linked to both allergic sensitization and HAV exposure (adjusted OR 1.15, 95% CI: 0.60-2.19, P=0.66).

CONCLUSIONS

In a population with high prevalence of HAV exposure, no significant association between HAV exposure and allergic sensitization is observed after controlling for the confounding effect of age.

High prevalence of storage mite sensitization in a general adult population

BACKGROUND AND AIM

Occupational and nonoccupational storage mite (SM) allergy has received considerable attention in recent years. The study aimed to evaluate both the prevalence and factors associated with sensitization to SMs in a general adult population from a warm and humid area where mites are the predominant allergens.

PATIENTS AND METHODS

An age-stratified random sample of 720 subjects was drawn from the population older than 18 years of A-Estrada (Galicia, Spain). From 697 eligible subjects, 469 (67%, median age 54 years, range 18-92 years, 44% males, 75% of cases from a rural environment) agreed to participate. Skin prick tests to SMs (Lepidoglyphus destructor and Tyrophagus putrescentiae), house dust mite (Dermatophagoides pteronyssinus), pollens, moulds and animal danders were performed in all cases. Wheals >or= 4 mm were considered positive. Epidemiological data were assessed by questionnaire. A design-based analysis was performed and all calculations were weighted to give unbiased estimates.

RESULTS

Tyrophagus putrescentiae and L. destructor were the leading causes of allergic sensitization throughout all ages. SM sensitization was found in 104 cases (weighted value 24.4%, 95% CI 20.6-28.2). SM sensitization was inversely associated with age. Multivariate analysis showed that SM sensitization was not significantly associated with sex, smoking, educational level, farming profession, rural environment, indoor humidity, presence of pets, livestock or grain storage facilities near home.

CONCLUSIONS

SMs (T. putrescentiae and L. destructor) are major aeroallergens in adults in the region studied, even in subjects without occupational exposure.

Association of alcohol consumption with total serum immunoglobulin E levels and allergic sensitization in an adult population-based survey

BACKGROUND

Chronic alcoholism is associated with increased total serum IgE levels.

OBJECTIVE

The study aimed to investigate the relationship between alcohol intake and both total serum IgE levels and allergic sensitization in a general adult population.

MATERIALS AND METHODS

A total of 720 subjects was randomly selected (stratified by age) from the population older than 18 years of A-Estrada (Spain) and invited to participate in the study. From 697 eligible subjects, 469 (67%, median age 54 years, range 18 to 92 years, 44% males, 75% of cases from a rural environment) agreed to participate. A battery of 13 skin prick tests to common aeroallergens was performed in all subjects. Cases with at least one positive test (n = 121, 26%) were considered to have allergic sensitization. The most frequent sensitisers were mites and pollens (24% and 10% of subjects, respectively). Total serum IgE was measured in 465 subjects (99%). Alcohol consumption was registered as the number of standard (approximately 10 g) drinking units habitually consumed per week. A total of 244 subjects (52%) were alcohol consumers (median intake, 14 units/week, range 1 to 147 units/week). Abstainers (n = 225, 48%) constituted the reference category.

RESULTS

Alcohol consumption of more than 14 units/week was associated with an increase in serum IgE levels after adjusting for age, gender, allergic sensitization and smoking (P = 0.02). Alcohol consumption was not significantly associated with either overall allergic sensitization or mite sensitization after adjusting for age, gender and smoking. However, alcohol consumption of more than 14 units/week was associated with an increased prevalence of pollen sensitization (adjusted OR 3.15, 95% CI 1.19 to 8.34, P = 0.02).

CONCLUSION

Alcohol consumption above a certain threshold is associated with an increase in total serum IgE levels. Alcohol consumption may also be associated with an increased prevalence of pollen sensitization.