Co-infection with Ascaris lumbricoides modulates protective immune responses against Giardia duodenalis in school Venezuelan rural children

We evaluated the effect of Ascaris lumbricoides on Giardia duodenalis infection and TH1/TH2 type immune mechanisms toward this parasite in 251 rural parasitized and 70 urban non-parasitized school children. The children were classified according to light (0-5000 eggs/g faeces) or moderate (>5001-50,000 eggs/g faeces) A. lumbricoides infection. Anti G. duodenalis skin hyper-reactivity, IgE, IgG, IL-13, IFN γ, IL6 and IL-10 levels were compared among G. duodenalis infected and non-infected children according to light or moderate A. lumbricoides infection. It was found that 62% of the A. lumbricoides moderately infected children were co-infected by G. duodenalis compared to 45% of the lightly infected group. After treatment, 42% of the A. lumbricoides moderately group were infected with G. duodenalis compared to 11% of their lightly counterparts, being A. lumbricoides IL-10 levels higher (p<0.0001) in the moderately infected group. In the A. lumbricoides lightly parasitized children, G. duodenalis infection was associated to a significant increase (p<0.005) of the levels of G. duodenalis IL-13, IFN-γ, IL-6, IgE, IgG and skin test hyper reactivity. In contrast, there was no effect of G. duodenalis infection in the elevation of these parameters among the A. lumbricoides moderately parasitized group, being those levels similarly lower as those observed in the control group. Inverse correlations were found between the levels of anti G duodenalis antibodies, skin test hyper-reactivity and cytokines with the intensity of A. lumbricoides infection (p>0.0001) and A. lumbricoides IL-10 levels (p>0.0001), suggesting that co-infection with A. lumbricoides may affect both TH1 and TH2 type immunity against G. duodenalis that may play an important role in the susceptibility to the infection after chemotherapy in children from endemic areas.     

Ascaris lumbricoides-induced interleukin-10 is not associated with atopy in schoolchildren in a rural area of the tropics

BACKGROUND: In areas where intestinal helminth infections are endemic, infections by these parasites may protect against skin test-measured reactivity to allergens, and it has been suggested that interleukin (IL)-10 may mediate this effect. This study investigated whether IL-10 and populations of IL-10+ T cells may modulate atopy in children living in an area where intestinal helminth infections are endemic. METHODS: Ecuadorian schoolchildren from rural communities were assessed for skin test-measured reactivity to Periplaneta americana allergen and Dermatophagoides pteronyssinus allergen. Blood samples were collected from 39 skin test-positive and 41 skin test-negative children, and peripheral-blood leukocytes were cultured in the presence of Ascaris lumbricoides antigen, to measure IL-10 protein and the frequency of T cell populations expressing intracellular IL-10. We also investigated whether these immunological factors affected the association between allergen-specific IgE and skin test-measured reactivity to aeroallergens. RESULTS: There was no evidence of association between the level of A. lumbricoides-induced IL-10 protein or IL-10+ T cells and skin test-measured reactivity to allergens. The association between allergen-specific IgE and skin test-measured reactivity was not affected by the level of IL-10 protein or the frequency of IL-10+ T cells. CONCLUSIONS: The results of this study do not support the notion that IL-10 plays a role in modulating atopy in children living in a tropical area where intestinal helminth infections are endemic.     

Serum IgE, skin and radioallergosorbent tests for house dust and mites in asthmatic children

Thirty asthmatic children were given an intradermal skin test, total IgE measurements and the radioallergosorbent test (RAST) against house dust and house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae). Results of the intradermal skin test and RAST were highly positive with overall agreement in 95.6%. The correlation coefficient between the total IgE and the RAST to house dust was 0.35 (p less than 0.05). There was no significant difference between the total IgE and the RAST to D. pteronyssinus and D. farinae (p greater than 0.05). The highly significant correlation coefficient between house dust and house dust mites (D. farinae, p less than 0.0001; D. pteronyssinus, p less than 0.00001) was determined by RAST. House dust has been found to be the most important allergen in children in Taiwan. The role of mites as a possible allergen in house dust also showed a highly significant correlation in our study.     

Specific allergen immunotherapy: effect on immunologic markers and clinical parameters in asthmatic children.

BACKGROUND: Specific allergen immunotherapy (SIT) is the main treatment modality for achieving long-term symptom relief in perennial allergic diseases. OBJECTIVE: The aim of this study was to evaluate the effect of 1 year of house dust mite immunotherapy on the concentrations of 3 immunologic markers: eosinophil cationic protein (ECP), nitric oxide (NO), and monocyte chemoattractant protein 1 (MCP-1). We also compared the effect on asthma symptoms and medication scores, allergen-specific bronchial challenge test, and the skin prick test. METHODS: A total of 31 mite-allergic, asthmatic children (age range, 6-16 years) were enrolled; 19 were treated with SIT and 12 controls who had refused SIT received only drug treatment. Efficacy was evaluated using serum NO, ECP, and MCP-1 levels, and asthma symptom and medication scores, allergen-specific bronchial challenge test, and skin-prick test. The results of the tests were compared at baseline and after 1 year of treatment. RESULTS: Serum NO and ECP levels decreased significantly in the SIT group (P = .01 and P = .018) compared to baseline, whereas control group values remained similar. The serum MCP-1 level decreased significantly in both the SIT and control groups (P = .009 and P = .041, respectively). The SIT group experienced significant improvement in asthma symptoms (P = .001) and medication scores (P = .001) and skin reactivity to Dermatophagoides pteronyssinus (P = .020), whereas the control group did not. The results of bronchial challenge to D pteronyssinus showed a similar pattern at baseline and after 1 year of treatment in both groups. The tolerated allergen concentration increased in both groups (P < .05). Lung function tests, total immunoglobulin (Ig) E and specific IgE to D pteronyssinus and Dermatophagoides farinae did not change after a year of treatment in either group. CONCLUSION: SIT with D pteronyssinus improves immunological and clinical parameters in mite-allergic asthmatic children after 1 year of treatment. The skin prick test may be used as a marker of efficacy of therapy.     

Absence of relationships between tuberculin responses and development of adult asthma with rhinitis and atopy

OBJECTIVE: To investigate the relationship between tuberculin skin responses and the development of adult asthma, rhinitis, and atopy. METHODS: Two hundred fourteen patients with mild-to-moderate asthma accompanied with rhinitis and 220 normal volunteers underwent a medical history, chest radiography, allergen skin-prick testing (SPT), bovine Mycobacterium tuberculosis vaccine (BCG) scar identification, purified protein derivative (PPD) tuberculin skin testing, serum-total and serum-specific IgE measurements, and bronchial provocation (provocative dose of histamine causing a 20% fall in FEV(1) [PD(20)]). RESULTS: Thirty-one normal volunteers (14.1%) and 168 asthma-rhinitis subjects (78.5%) had one or more positive skin test results (p < 0.0001). Neither the presence of a BCG scar nor a history of BCG vaccination had a significant effect on atopy in either group. The rate of PPD positivity had no statistical difference between atopy and nonatopy in both groups. In multivariate logistic regression analysis, the odds ratio for tuberculin reactivity was not related to the level of serum-total IgE nor to the level of serum-specific IgE to Dermatophagoides pteronyssinus (DP) and Dermatophagoides farinae (DF), skin response to DP and DF, and PD(20). Overall, no significant correlations were found between tuberculin skin reactivity and log serum-total IgE or PD(20). CONCLUSION: There is no relationship between history of tuberculosis infection, tuberculin responses, and development of adult bronchial asthma, allergic rhinitis, and atopy. Our study suggests that the protection provided by intradermal BCG vaccination in infants to prevent atopic diseases may be limited in early childhood, when a substantial memory of cellular immune modulation still exists.     

Age, gender and reactivity to allergens independently influence skin reactivity to histamine.

BACKGROUND. The ability to mount an IgE response to allergens is a prerequisite for the development of positive allergen skin tests. Histamine is commonly used as a positive control in skin prick testing and provides a measure of nonspecific skin reactivity, similar to bronchial hyper-responsiveness. METHODS. To determine whether allergen responsiveness, age, gender and season of the year contribute to histamine sensitivity, 620 subjects (502 of them with at least one known sensitizing allergen and the remaining 118 non-allergic controls) were prick-tested with a panel of allergens common in the Northern Italy semi-rural area where the patients lived, and with 10 mg/ml histamine dihydrochloride. RESULTS. We found higher histamine reactivity in allergic versus control individuals (median value 23.7 versus 19.8 mm2; p=0.0497). Likewise, we found in allergic subjects a correlation between allergen responsiveness in terms of number of positive allergens at skin prick test and sensitivity to histamine (mono- sensitized versus poly-sensitized subjects: p=0.0015). Moreover older age and male sex were associated with a higher response to histamine, also when separately considering allergic subjects (p<0.0001 in both cases: correlation coefficient for age versus histamine reactivity: r=0.3408). The correlation between allergen responsiveness and sensitivity to histamine was maintained also when statistically balanced for age and sex. CONCLUSION. Allergen responsiveness, gender and age allow more accurate prediction of histamine sensitivity than either parameter alone.     

Epidemiology, diagnosis and treatment of the house-dust-mite allergy in asthmatic children

Authors introduced as the first in Yugoslavia the method of isolation and classifying Dermatophagoides pteronyssinus out of house dust using the first the help of Spieksma, Cunnington and Araujo, later on by themselves in new established laboratory. In house dust of 290 houses of asthmatic children in 88 (30,8%) through of cases mites were found, mostly Dermatophagoides pteronyssinus. 212 asthmati children who did not react well to specific hyposensitisation with standard house dust extract showed an allergy to house dust mites in 76 (35,8%), who were successful treated with allergen extract Dermatophagoides pteronyssinus with the cutaneous method of hyposensitisation. House dust mites allergy has clinical importance in asthmatic children for pathogenesis of asthma bronchiale in childhood as well in adults. IgE values in the serum after the radioimmunological method in asthmatic and healthy children has been estimated. In asthmatic children we found statistical significant higher of IgE values in the serum as in healthy children, this is probably caused by the infestation from Ascaris lumbricoides. Asthmatic children were significant stengher infesteds the healthy children.     

In vivo and in vitro sensitization to domestic mites in German urban and rural allergic patients.

Sensitization to domestic mites is common in Germany. The main objectives of this study were (1) to establish the rate of skin test sensitivity to Dermatophagoides pteronyssinus, Acarus siro, Lepidoglyphus destructor, and Tyrophagus putrescentiae in 512 consecutive patients evaluated for upper and/or lower respiratory complaints; (2) to verify how many of the patients with a positive skin test to at least one of the three storage mites were also skin test positive to D. pteronyssinus; and (3) to verify how many of the patients with at least one positive skin test to one of the storage mites previously mentioned were also sensitized, in vitro, to other mite species. A total of 512 consecutive patients with rhinitis and/or asthma, living in urban or rural areas of central Germany were skin tested with extracts of D. pteronyssinus, A. siro, L. destructor, and T. putrescentiae. In addition, specific IgE determinations to Euroglyphus maynei, Blomia tropicalis, Blomia tjibodas, Blomia kulagini, and Gohieria fusca were conducted in those individuals with a positive skin test to at least one of the storage mites used in skin testing. Of the 512 patients, 103 (20.1%; 77 urban dwellers and 26 farmers) reacted to at least one of the storage mites. From this latter group, 88 individuals (85.4%) also skin tested positive to D. pteronyssinus. In vitro specific IgE determinations revealed a high rate of sensitization to the other mite species studied. We conclude that sensitization to storage mites in Germany is frequently associated with sensitivity to D. pteronyssinus. Overall, skin test sensitivity to storage mites was greater in rural than in city dwellers. In vitro sensitization to B. tjibodas was also significantly greater in rural than in city dwellers.     

Analysis of -675 4 g/5 G SERPINE1 and C-159T CD14 polymorphisms in house dust mite-allergic asthma patients

BACKGROUND: Experimental studies indicate that endogenous plasminogen activator inhibitor-1 (PAI-1, encoded by the gene SERPINE1) modulates the immune response to lipopolysaccharide (LPS). On the other hand, LPS induces PAI-1 secretion. Activation of individual cells by LPS is facilitated by CD14. The single nucleotide polymorphisms -675 4G/5G in SERPINE1 and C-159T in CD14 are major determinants of PAI-1 and CD14 expression, respectively. OBJECTIVE: To evaluate the frequency of the -675 4G/5G SERPINE1 and C-159T CD14 polymorphisms in house dust mite (HDM) allergic asthma patients. METHODS: The polymorphisms were evaluated in unrelated inhabitants of northeastern Poland, including 372 HDM-allergic asthmatic patients and 160 healthy nonatopic control subjects using polymerase chain reaction. RESULTS: Both the C allele of CD14 and the 4G allele of SERPINE1 were more frequently encountered in HDM-allergic asthmatic patients than in healthy control individuals. When the 5G/5G-TT/CT genotype was considered as a nonrisk genotype, all other genotypes were associated with asthma. The odds ratios ranged from 3.96 (95% confidence interval, 1.56-10.1) for the 5G/5G-CC genotype to 10.7 (95% confidence interval, 5.1-24.9) for the 4G/4G-CC genotype. Bronchial reactivity to histamine and total serum immunoglobulin (Ig) E levels were predominantly associated with the 4G/5G SERPINE1 variants, while bronchial reactivity to Dermatophagoides pteronyssinus and serum concentrations of specific IgE against D pteronyssinus were predominantly associated with the C/T CD14 variants. Patients with 4G/4G-CC genotype had the lowest forced expiratory volume in 1 second and the highest bronchial reactivity. CONCLUSION: The SERPINE1 and CD14 polymorphisms studied here are associated with different aspects of bronchial reactivity and IgE response. Our results indicate that PAl-1 and CD14 may interact to affect susceptibility to allergic asthma.     

Serum IgE,Skin and Radioallergosorbent Tests for House Dust and Mites in Asthmatic Children

Thirty asthmatic children were given an intradermal skin test, total IgE measurements and the radioallergosorbent test (RAST) against house dust and house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae). Results of the intradermal skin test and RAST were highly positive with overall agreement in 95.6%.

The correlation coefficient between the total IgE and the RAST to house dust was 0.35 (p<0.05). There was no significant difference between the total IgE and the RAST to D. pteronyssinus and D. farinae (p<0.05). The highly significant correlation coefficient between house dust and house dust mites (D. farinae, p<0.0001; D. pteronyssinus, p<0.00001) was determined by RAST. House dust has been found to be the most important allergen in children in Taiwan. The role of mites as a possible allergen in house dust also showed a highly significant correlation in our study.     

Significant improvement of specific bronchial hyperreactivity in asthmatic children after 4 months of treatment with a modified extract of dermatophagoides pteronyssinus.

BACKGROUND: The clinical efficacy of allergen immunotherapy using therapeutic vaccines containing modified allergen extracts has been previously shown. OBJECTIVE: To evaluate the clinical efficacy of a vaccine containing depigmented, polymerized extract of Dermatophagoides pteronyssinus in asthmatic children, monosensitized to mites, after 4 months of treatment. MATERIAL AND METHODS: A total of 30 mite-allergic, asthmatic children (age range, 8-16 years) were entered in the study; 15 were treated with the modified allergen extract (active group) and 15 received only pharmacologic treatment (control group). The study was open, controlled and parallel with random allocation of the patients to each of the groups. Efficacy was evaluated using allergen-specific bronchial challenge tests, dose-response skin-prick tests, and symptom and medication scores. The results of the bronchial challenges and dose-response skin-prick tests were compared at baseline and after 4 months of treatment. The build up phase consisted of 4 injections in 2 days, followed by 4 injections of the maintenance dose. RESULTS: All patients of the active group concluded the study, whereas 2 of the control group did not. In the active group, there was a significant difference in the PC20FEV1 (P <.01) after 4 months. The mean allergen quantity needed was 26 microg at baseline vs. 309 microg after 4 months (a 12.8-fold increase). There was no difference in the control group (5 tg at baseline vs 8 microg at the end). A significant reduction in the number of cases with dual bronchial response was observed in the treated group (P < .05). Two treated patients of this group experienced a negative bronchial challenge after 4 months of treatment. The group of active patients also experienced significant improvement in skin reactivity and symptom and medication scores. CONCLUSIONS: Vaccines containing depigmented polymerized extracts of D pteronyssinus are safe and effective in the treatment of mite allergic asthmatic children, and provide clinical benefit after 4 months of treatment.     

Human basophil releasability. VI. Changes in basophil releasability in patients with allergic rhinitis or bronchial asthma.

We evaluated basophil releasability in two groups of allergic patients with positive skin tests to Dermatophagoides pteronyssinus major allergen (Der p l) (29 adults with bronchial asthma and 17 with allergic rhinitis) and in 31 age-matched normal donors. Both basophil reactivity (maximal percent histamine release) and basophil sensitivity (the concentration that causes 50% of maximal percent histamine release: HC50) to Der p l in patients with asthma were similar to those in patients with allergic rhinitis. On the contrary, basophil reactivity to anti-IgE was significantly higher in patients with asthma (58.0 +/- 3.6%) than in patients with allergic rhinitis (46.3 +/- 5.2%; p less than 0.05). Both groups of patients showed an increased releasability compared to control subjects (27.3 +/- 4.6%; p less than 0.001), whereas there were no significant differences in basophil sensitivity to anti-IgE among the three groups of donors. Differences were also found with respect to basophil reactivity and sensitivity to f-met peptide, whereas no differences appeared when basophils from the three groups of donors were challenged with the Ca2+ ionophore A23187. There was a significant correlation between basophil reactivity and sensitivity to Der p l and to anti-IgE in both asthmatic and allergic rhinitis patients. A significant correlation was found between basophil reactivity and sensitivity to anti-IgE and serum IgE level only in patients with bronchial asthma, whereas no correlations were found in patients with allergic rhinitis. There was no correlation between in vivo mast cell releasability and in vitro basophil releasability in response to Der p l in either group of allergic patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Wheezing,allergy, and parasite infection in children in urban and rural Ethiopia

Epidemiological studies in developing countries suggest that intestinal parasite infection may reduce the risk of asthma. Because this evidence is all derived from adults and older children, we have investigated the relation between parasite infection, wheezing, and allergen skin sensitization in nested case-control studies drawn from a survey of 7,155 children aged 1 to 4 years living in urban and rural areas of Jimma, Ethiopia. Infection with parasites was common, predominantly with Trichuris (54%), Ascaris (38%), and hookworm (10%). Wheezing in the past year was significantly more prevalent in urban (4.4%) than rural children (2.0%), and was less prevalent in those infected with Ascaris (age, sex, and urban/rural adjusted odds ratio, 0.5; 95% confidence interval, 0.3 to 0.9), particularly in relation to high-intensity infection. Similar, although nonsignificant, associations were found for hookworm (adjusted odds ratio, 0.6; 95% confidence interval, 0.2 to 1.8), but there was no suggestion of any relation to Trichuris infection. Dermatophagoides pteronyssinus and cockroach (Blattella germanica) skin sensitization was more prevalent in rural than urban children, and was unrelated to wheeze. We conclude that Ascaris and possibly hookworm infection protects against wheeze in young Ethiopian children, and that this effect is not mediated by inhibition of allergen sensitization.     

Allergic symptoms,atopy, and geohelminth infections in a rural area of Ecuador

Geohelminth infections may affect the expression of allergic disease. To investigate the relationship between geohelminth infections, atopy, and symptoms of allergic disease, we studied 4433 schoolchildren from 71 schools in a rural tropical area in Ecuador. Information was collected on allergic symptoms, allergen skin test reactivity, and presence of geohelminth infections. Allergic symptoms were of low prevalence (2.1% had recent wheeze), but prevalence of skin test reactivity was relatively high (18.2%). The presence of geohelminth infections was protective against allergen skin test reactivity (odds ratio 0.62, 95% confidence interval 0.50-0.76, p < 0.001) and symptoms of exercise-induced wheeze (odds ratio 0.59, 95% confidence interval 0.40-0.87, p = 0.008) but not against other wheeze symptoms or symptoms of allergic rhinitis or atopic eczema. Infection intensity with Ascaris lumbricoides or Trichuris trichiura was associated with a reduction in the prevalence of allergen skin test reactivity but not with allergic symptoms. There was no evidence of interactions between geohelminth infection and allergen skin test reactivity on the risks of allergic symptoms. The results suggest that geohelminth infections do not explain the low prevalence of allergic symptoms in the study population.     

Serum Specific IgE Reactivity to Recombinant Der f 11 in Asthmatic Children

This study was designed to examine the prevalence of positive serum IgE reactivity to the recombinant group11 Dermatophagoides farinae allergen (rDer f 11) in asthmatic children in Taiwan. Using immunoblot analysis in a preliminary study of 18 asthmatic children, 13 (72.2%) reacted positively to rDer f 11 and 16 (88.9%) showed positive reactivity to D. farinae extracts. The allergenicity of rDer f 11 was further evaluated with in vivo skin tests and in vitro IgE immunodot assays in 24 mite skin-test-positive asthmatic children. Whereas 17 (70.8%) had positive skin tests to rDer f 11, 18 (75.0%) had positive serum IgE reactivity to rDer f 11. A good coincidence (87.5%) between the immunodot assay and the skin test was confirmed in these asthmatic children. Moreover, the prevalence of serum IgE reactivity to rDer f 11 was further investigated in a large panel of 49 mite skin-test-positive asthmatic children. Again, 38 (77.6%) had positive serum IgE reactivity to rDer f 11 in immunodot assays. Taken together, the positive IgE reactivity to rDer f 11 in immunodot analysis ranged from 75 to 77.6% in two groups of 73 mite skin-test-positive asthmatic children. High incidence of serum IgE antibodies specific for rDer f 11 in the present study suggests that Der f 11 is a novel major allergen of house dust mites.     

Prevalence of respiratory and atopic disorders among children in the East and West of Germany five years after unification.

Living conditions in eastern Germany have changed rapidly since unification in 1990 and little is known about how these changes affect the prevalence of atopic diseases. This study describes methods and prevalences of a large epidemiological project investigating determinants of childhood asthma and allergies in eastern (Dresden and Leipzig) and western (Munich) Germany in 1995/1996. Community based random samples of 9-11 yr old children in Dresden (n=3,017) and Munich (n=2,612), and of 5-7 yr old children in Dresden (n=3,300), Leipzig (n=3,167) and Munich (n=2,165) were studied by parental questionnaires, bronchial challenges with hypertonic saline, skin examination, skin-prick tests, and measurements of specific and total serum immunoglobulin (Ig)E using Phase II modules of the International Study of Asthma and Allergies in Childhood (ISAAC). In 9-11 yr old children, the prevalence of physician diagnosed asthma (7.9% versus 10.3%; p<0.01) and bronchial hyperresponsiveness (15.7% versus 19.9%; p<0.05) was lower in Dresden than in Munich. No difference between Munich and Dresden was observed in the prevalence of diagnosed hay fever, skin test reactivity to > or = 1 allergen, and increased levels (>0.35 kU x L(-1)) of specific IgE against inhalant and food allergens. Symptoms and visible signs of atopic eczema tended to be more prevalent in Dresden. Similar East-West differences between the three study areas were seen in the younger age group. These findings are in line with recently observed increases in the prevalence of hay fever and atopic sensitization, but not of asthma and bronchial hyperresponsiveness, among 9-11 yr old children in Leipzig.     

Discriminant analysis in allergic rhinitis and asthma: methacholine dose-response slope allows a good differentiation between mild asthma and rhinitis

Asthma and rhinitis frequently coexist in allergic patients, but nasal symptoms may predominate, leading to asthma underdiagnosis and undertreatment. Discriminant analysis obtains the best differentiation between groups using one or one set of variables. Our aim was to identify the laboratory test [allergen exposure, total and specific serum IgE, lung function, blood eosinophils and, bronchial response and sensitivity to methacholine (Mth) and allergen] or combination of them that allowed the best differentiation between mild asthma and allergic rhinitis. A cross-sectional analysis was performed in 86 Dermatophogoides pteronyssinus allergic rhinitis patients, who were classified according to clinical data as rhinitis plus mild asthma (n = 62) or "pure" rhinitis (n = 24). Bronchial symptoms had been exhaustively evaluated during a 2-years pre-inclusion period. Patients underwent skin tests and bronchial challenge with Mth and allergen. The exposure to D. pteronyssinus allergen (Der pl) was quantified in dust samples. Dose-response curves with Mth [until the FEV1 fell by 40% or the maximal dose (200 mg/ml) was inhaled] were attained. We developed multiple models of discriminant analysis in order to evaluate the capacity of the above variables to differentiate groups. Asthma patients had higher total and specific IgE levels and a greater sensitivity (PD20 values) and response [dose-response slope (DRS)] to both Mth and allergen. The model entering these variables was the one that correctly classified more patients (79.2%). The discriminative power of the model that only included Mth-DRS values was similar to the above (78.8%). Bronchial response to Mth is quantitatively different in allergic rhinitis patients who display mild asthma symptoms when compared to those that only report rhinitis, suggesting a distinct bronchial intrinsic behavior. The utilization of complete dose-response curves with Mth allows a good separation between mild asthma and "pure" rhinitis patients and might be useful in the diagnosis of mild asthma. Whether the early detection and treatment of these patients prevents the development of symptomatic asthma needs further evaluation.     

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.     

Round table: Importance of allergens in childhood asthma. Introduction

Asthma is the most frequent chronic disease in childhood. Its prevalence varies (in Spain between 12 % in coastal regions and 6 % in the Castilian plateau). Asthma represents chronic inflammation of the airways associated with an increase in bronchial reactivity to various stimuli, leading to reduced air flow and subsequent remodeling of the bronchial wall. Asthma usually begins in the first few years of life and 30 % of patients will continue to be asthmatic throughout their lives. The main characteristic associated with the persistence of asthma in adulthood seems to be allergy. Another risk factor is the presence of bronchial hyperreactivity. Wheezing associated with viral infections in childhood shows a favorable outcome when not associated with atopic features. The atopic disposition is caused by the interaction between genetic and distinct environmental factors (allergens), as well as by the various clinical manifestations that favor a mainly Th2 response, with interleukins that lead to the formation of specific IgE, pro-inflammatory cytokines, bronchial hyperreactivity, etc. In most cases, asthma is mainly an allergic process, mediated by an IgE mechanism. Inhalation of allergens is considered the most important cause of the onset of asthma in predisposed children. First the presence of an allergen gives rise to sensitization, with the formation of specific IgE. In a subsequent contact, mediators are released, with inflammatory response of the airways and an increase in bronchial hyperreactivity. If the presence of the allergen is prolonged, inflammation and subsequent healing may lead to irreversible damage to the bronchial wall and permanent deterioration of respiratory function. In children with asthma, the aim is to modify the natural history of the disease and prevent its persistence in adulthood. This involves identifying the allergen or allergens causing the symptoms, confirming the role of these allergens in clinical manifestations through specific challenge tests and, lastly, indicating the treatment be followed.