Characteristic features of cockroach hypersensitivity in Turkish asthmatic patients

Cockroach exposure and its allergy sensitization in asthma patients

Asthma is a heterogeneous disease with distinct phenotypes. Serum tIgE, SSIgE and SPT are the methods of evaluating allergen sensitization. The present study evaluates the exposure and sensitization to cockroach (Periplaneta americana) antigens in asthma patients in a metropolitan city of India. The study enrolled 200 consecutive bronchial asthma patients, diagnosed as per GINA guidelines. As per history of exposure to cockroaches, the patients are divided in two groups as exposed and non-exposed asthmatic. All the enrolled subjects underwent SPT against common aeroallergens including cockroach, spirometry and estimation of tIgE level and SSIgE against cockroach. Out of 200 asthma patients, a total of 114 (57%) asthmatic were found SPT positive against one of the common aeroallergens, of which 68 (34%) showed SPT sensitivity against cockroach. A total of 103 (51.5%) patients were found exposed to cockroaches. In the cockroach exposed group, the mean serum tIgE was found significantly higher than the non-exposed group (569.31±224.64 vs 479.29±237 IU/ml; p=0.007). The mean SSIgE against cockroach in exposed groups was found not significant than non-expose group (4.87±11.19 vs 4.11±8.39 KUA/L; p=0.589). The mean tIgE was also not significant in atopic compared to non-atopic asthmatic (553.25±218.12 IU/ml vs 489.1±251.16 IU/ml; p=0.056). The mean SSIgE against cockroach was 5.66±10.45 KUA/L for atopic and 2.96±8.98 KUA/L for non-atopic (p=0.054). The airway obstruction was almost the same in both groups.  Asthmatic patients who were exposed to cockroach and atopic had high tIgE, SSIgE levels and SPT positivity against cockroach antigen compared to non-exposed patients.

Minimum prick test panel for adult patients with asthma and rhinitis in Ankara, Turkey

OBJECTIVE

Determination of the number and type of allergens needed to be tested in epidemiological studies is important in order to identify most of the sensitized subjects with a cost-effective approach. This study aimed to investigate the minimum skin prick test panel for the identification of at least 95% of the sensitized subjects with symptoms of asthma and/or allergic rhinitis (AR) in Ankara, Turkey.

METHODS

Skin prick test results of 7492 patients who were referred to our outpatient clinic with clinical symptoms of asthma and/or AR between 1991 and 2005 were evaluated retrospectively. Seven allergens were tested in all and 13 allergens in 4202 patients. The allergen group needed for detection of 95% of the sensitized subjects was determined for both the 7 and 13 allergen panels. The study protocol was approved by the local ethics committee of Hacettepe University.

RESULTS

The atopy prevalences in the whole study population and in 4202 patients tested with the 13 allergen panel were calculated as 32.2% and 42.6%, respectively. Three allergens (Phleum pratense, Dermatophagoides pteronyssinus and Artemisia vulgaris) within the 7 allergen panel were adequate for the identification of at least 95% of the sensitized subjects. Olea europae was added to the previous three allergens when the 13 allergen panel was applied.

CONCLUSION

Three to four allergens are sufficient for identification at least 95% of sensitized subjects with asthma and/or AR in Ankara, Turkey.

Group 10 allergens (tropomyosins) from house-dust mites may cause covariation of sensitization to allergens from other invertebrates

Group 10 allergens (tropomyosins) have been assumed to be a major cause of cross-reactivity between house-dust mites (HDMs) and other invertebrates. Despite all of the published data regarding the epidemiology, percent IgE binding and level of sensitization in the population, the role of tropomyosin as a cross-reactive allergen in patients with multiple allergy syndrome still remains to be elucidated. Homology between amino acid sequences reported in allergen databases of selected invertebrate tropomyosins was determined with Der f 10 as the reference allergen. The 66.9 and 54.4% identities were found with selected crustacean and insect species, respectively, whereas only 20.4% identity was seen with mollusks. A similar analysis was performed using reported B-cell IgE-binding epitopes from Met e1 (shrimp allergen) and Bla g7 (cockroach allergen) with other invertebrate tropomyosins. The percent identity in linear sequences was higher than 35% in mites, crustaceans, and cockroaches. The polar and hydrophobic regions in these groups were highly conserved. These findings suggest that tropomyosin may be a major cause of covariation of sensitization between HDMs, crustaceans, and some species of insects and mollusks.

Occupational health risks due to shipboard cockroaches

OBJECTIVES

In various investigated populations, sensitization to cockroaches was observed in 8% of screened subjects from temperate climatic zones and in 36% of those from tropical zones. Because of the numerous hiding places and food storages aboard a ship the crews can be highly exposed to cockroaches. The aim of this study is to assess the prevalence of sensitization to cockroaches and potentially associated health risks in seafarers.

METHODS

In July 2005, a total of 145 seamen sailing under the German flag were recruited from a medical surveillance program for a cross-sectional study (response 95.4%). A standardized interview and a skin prick test (SPT) with nine common inhalant allergens and a cockroach extract (Blatella germanica) were performed. In cockroach-sensitized seafarers total and cockroach-specific IgE was measured and lung function tests conducted.

RESULTS

In total, 39 seamen (26.9%) were cockroach-sensitized according to SPT results. Presence of cockroach sensitization in seamen from the tropical zone (37.3%) was significantly higher than in seamen from the temperate zone (21.3%) (odds ratio 2.20, 95% confidence interval 1.04-4.66). The prevalence of sensitization to any of the other nine common allergen mixtures tested was lower (between 2.1 and 12.4%). Neither current or past cockroach exposure on board nor cumulative cockroach exposure and time since last cockroach exposure were associated with cockroach sensitization. Among cockroach SPT-positive seamen, cockroach-specific IgE was detected in 52.8%. Five out of 37 (13.5%) SPT-positive seamen exhibited an obstructive ventilation pattern. The prevalence of work-related atopic symptoms was 9.0% (n = 13). These symptoms were not related to cockroach sensitization.

CONCLUSION

The high prevalence of sensitization to cockroaches among seamen in the presented study emphasizes the strong sensitization potency of these insects. Longitudinal studies and bronchial cockroach challenge tests are necessary to assess the clinical relevance of cockroach sensitization aboard a ship in more detail.

Skin prick test results of child patients diagnosed with bronchial asthma

BACKGROUND

The pathogenesis of asthma is associated with both genetic and environmental factors. Allergen sensitization is an important risk factor in asthma development.

AIM

To evaluate sensitivity to allergens by using the skin prick test in patients with a diagnosis of bronchial asthma.

METHOD

Patients with a diagnosis of bronchial asthma followed-up at the Ministry of Health, Diskapi Children's Diseases Training and Research Hospital in Ankara (Turkey) between January 1995 and March 2000 were included. Sensitivity to allergens, as determined by the skin prick test, was evaluated retrospectively.

RESULTS

The files of a total of 3025 children (63.3 % boys) with bronchial asthma, aged 3 months to 16 years were evaluated. Of the total, 1667 patients with a diagnosis of bronchial asthma and 1358 with bronchial asthma plus allergic rhinitis were under follow-up. Of the 3025 asthmatic patients, 1902 had undergone the skin prick test and 60.3 % of these patients were atopic. The most common allergens were house dust mite [726 patients (63.3 %)], followed by pollens [565 patients (49.3 %)]. The most common allergen within this group was grass pollens [348 patients (30.3 %)].

CONCLUSIONS

Atopy was an important risk factor in our patients and the most common allergens were aeroallegens. The development of sensitization could be delayed by early precautions.

Evaluation of the relationship between cockroach sensitivity and house-dust-mite sensitivity in Turkish asthmatic patients

Exposure to cockroach has been identified as an important source of indoor allergens in patients with asthma and allergic rhinitis. We evaluated the relationship between cockroach sensitivity and other allergens in patients with asthma. A total of 114 patients, defined asthma according to GINA, were enrolled in this study. A questionnaire including age, sex, duration of asthma, history of cockroach presence at home, and total IgE, blood eosinophil count, pulmonary function tests, standard skin prick test additional cockroach and shrimp allergen were performed. There were 84 (73.7%) female and 30 (26.3%) male patients with a mean age of 38.1+10.1 years. The average duration of asthma was 7.7+7.2 years. Sixty five (57%) patients were determined atopic and 49 (43%) nonatopic. Pollen allergen was the most common allergen in 59 (51.8%) patients with asthma, and second common allergen was mite allergen in 43 (37.7%) patients. Cockroach sensitivity were detected in 23 (20.2%) of 114 all asthmatics and 23 (35%) of atopic asthmatics. High rates of house-dust-mite allergy (73.9%) was determined in patients with cockroach sensitivity (P<0.05), while we found no relationship with other allergens. There was no difference for cockroach sensitivity between rural and urban population. Cockroach sensitivity was more common in mild bronchial asthmatics and a female predominance was observed. In addition, there was no association between shrimp and cockroach sensitivity. As a result, a high rate of cockroach sensitivity alone or with mite sensitivity was seen in patients with bronchial asthma in Turkish population. Because of cross-reactivity between mites and cockroach, cockroach sensitivity should be investigated in patients with house-dust-mite allergy. In addition, a high rate of cockroach sensitivity, in terms of IgE sensitization, may be important for the development of new sensitizations.

Retrospective evaluation of epidermal skin prick tests in patients living in Aegean region

Sensitization to aeroallergens of Aegean region is not well decumented. In this study we evaluated the epidermal skin prick test results of the patients who applied to allergy outpatient department retrospectively. Epidermal skin prick test of the 5055 patients were evaluated. Of these patients 2638 (52 %) were female, 2417 (48 %) male, 1213 (24 %) adult and 3842 (76 %) pediatric patient, 1163 (23 %) patients were allergic rhinitis, 2477 (49 %) were bronchial asthma, 505 (10 %) were allergic rhinitis with bronchial asthma, 556 (11 %) were chronic urticaria, 253 (5 %) were wheezy infant and 101 (2 %) patients were atopic dermatitis, 2932 (58 %) had atopy history in their first and second degree relatives. Patients were aged between 3.5 months and 79 years (mean 14.1 3.2 years and median 11 years). In epidermal skin prick tests sensitization to house dust mites (D. farinae, D. pteroniyssinus), pollens (grass, cereals and trees), moulds, animal danders, foods (especially in early childhood) and cockroach were evaluated. Our data indicate that allergens that may be the cause of the high prevalence of allergic diseases in Izmir are probably produced by pollens and mites.

Possible association between cockroach allergy and HLA class II antigens

BACKGROUND

Susceptibility to the development of allergic diseases is known to be associated with genetic components, as well as environmental factors. Although the genetics of immunoglobulin E, atopy, and asthma are complex, genetic markers are needed to identify populations at risk and to plan intervention studies.

OBJECTIVE

Human leukocyte antigen (HLA) class II genes play a major role in the control of immune response. We investigated the association between HLA class II alleles of DRB1 and DQB1 and the expression of atopy in cockroach-sensitive patients.

METHODS

Levels of total and specific immunoglobulin E were determined. Skin prick tests were performed. HLA class II typing was performed by the Polymerase chain reaction with sequence-specific primers. Distribution of the HLA genotypes of 32 cockroach-positive atopic patients from the inner city were compared with those of 32 healthy, nonatopic controls of Turkish Caucasian origin.

RESULTS

HLA class II gene analysis showed an increase of the HLA-DRB1*0701 and HLA-DQB1*02 alleles in atopic patients compared with nonatopic controls (31.3% vs 3.1% and 50% vs 15.6%, Pc < 0.036 and Pc < 0.021, respectively). Conversely, HLA-DRB1*15 allele was encountered more frequently in the control subjects. An association between cockroach sensitivity and cutaneous reactivity to other aeroallergens was observed (P < 0.001).

CONCLUSIONS

It is suggested that the higher frequencies of HLA-DRB1*0701 and HLA-DQB1*02 alleles are probably related to atopy rather than an association between class II antigens and cockroach allergy in this group of polysensitized, atopic individuals. Further studies may lead to a better understanding of the genetically determined susceptibility, and evaluate the individual effects of each locus (or allele) on sensitivity to specific allergens in the Turkish population.

Regulatory action criteria for filth and other extraneous materials v. strategy for evaluating hazardous and nonhazardous filth

The U.S. Food and Drug Administration (FDA) uses regulatory action criteria for filth and extraneous materials to evaluate adulteration of food products. The criteria are organized into three categories: health hazards, indicators of insanitation, and natural or unavoidable defects. The health hazard category includes criteria for physical, chemical, and microbiological hazards associated with filth and extraneous materials. The health hazard category encompasses criteria for HACCP (Hazard Analysis and Critical Control Point) hazards and HACCP contributing factors. The indicators of insanitation category includes criteria for visibly objectionable contaminants, contamination from commensal pests, and other types of contamination that are associated with insanitary conditions in food processing and storage facilities. The natural or unavoidable category includes criteria for harmless, naturally occurring defects and contaminants. A decision tree is presented for the sequential application of regulatory action criteria for filth and extraneous materials associated with each category and with each type of filth or extraneous material in the three categories. This final report of a series in the development of a transparent science base for a revised FDA regulatory policy in the area of filth and extraneous materials in food includes a comprehensive list of the references that form the science base for the FDA regulatory policy.

Comparison of allergenic components between German cockroach whole body and fecal extracts

BACKGROUND

Cockroaches have been demonstrated to be an etiologic factor in allergic diseases. Further, sensitivity to cockroach places patients with asthma at risk for exacerbations that require emergency medical care.

OBJECTIVE

This study compared the differences in allergenic components between German cockroach whole body and German cockroach fecal extracts (GWBE and GFE).

METHODS

Patients with asthma and/or allergic rhinitis were skin prick tested with German cockroach extract (Bayer Corporation, West Haven, CT). Serum specimens from these patients, 25 with positive skin tests and 8 with negative tests, were used for the ELISA and immunoblot experiments.

RESULTS

By ELISA, 72% (18 of 25) and 60% (15 of 25) of positive responders' sera showed IgE antibodies to GWBE and GFE, respectively, and the IgE levels to GWBE were highly correlated with those to GFE (r = .84, P < .01). In inhibition ELISA experiments, extensive cross-reactivity was observed between GWBE and GFE, slight cross-reactivity between GWBE and Dermatophagoides farinae, and no cross-reactivity between GFE and D. farinae. The two-site monoclonal antibody ELISA detected more of the German cockroach major allergens in GFE compared with GWBE; 6.2 times (2420 vs 390 U/mL) for Bla g 1 and 3 times (15.32 vs 5.07 microg/mL) for Bla g 2. In the immunoblot comparison of patients' sera, the IgE antibodies binding to GWBE were apparently different from those binding to GFE in all the positive responders' sera; eg, 50% or more of the 25 positive responders' sera reacted to 43- to 67-kDa proteins in GWBE and to 28- to 30-kDa proteins in GFE, respectively. No IgE antibodies bound to components in GWBE and GFE in the 8 negative responders' sera.

CONCLUSIONS

There are major differences between the allergenic components of GWBE and GFE. Based on the amounts of major allergens (Bla g 1, Bla g 2), German cockroach feces are a more important source of allergen than the whole body in respiratory allergic diseases.

Exposure and allergic sensitization to cockroach allergen in East Germany

BACKGROUND

Some studies suggest that the prevalence of sensitization to cockroach allergens may be higher in the United States than in Europe, but there are no comparable data from population-based studies.

OBJECTIVES

To determine the prevalence of allergic sensitization to German cockroach (GCR) in German schoolchildren and to assess its clinical relevance; and to determine the exposure to the major GCR allergen Bla g 2 in non-selected homes and nurseries.

METHODS

The prevalence of allergic sensitization to GCR and other allergens was determined by measurement of specific IgE and skin-prick tests in a cross-sectional study of 2993 children aged 5-11 years in Dresden, Germany. The prevalence of atopic disease was determined by questionnaire, and pulmonary function and bronchial hyperresponsiveness to hypertonic saline were measured. Bla g 2 exposure was determined on floors of 187 kitchens and 47 nurseries by a commercial sandwich ELISA.

RESULTS

One hundred and twenty-seven (4.2%) of the children had specific IgE (> 0.7 kU/L) against GCR. Among children with current wheeze, 8.4% were GCR-sensitized. Compared to data from the United States, the prevalence of sensitization to cockroach was similar in children without asthma (3.9%), but less frequent in asthmatic children from Dresden (6.1%). After adjustment for positive reactions to other allergens (SX1 test) no significant impact of GCR sensitization on wheeze or other symptoms and diagnoses was found. Bla g 2 was detected in 29% of the kitchens and 43% of the nurseries. None of these sites had exposure levels above the proposed threshold for causing disease of 80 ng/g dust.

CONCLUSION

The data suggest that allergic sensitization to GCR is less frequent in asthmatics from Dresden, Germany than in US cities. The data indicate that GCR sensitization is not an independent risk factor for asthma and other atopic diseases in 5-11-year-olds from this city.