Enrique Fernández-Caldas

Endotoxin exposure and symptoms in asthmatic children

Endotoxins (ET) are pro‐innammatory substances present in hou.sc dust which may increase non‐specific bronchial reactivity in asthmatic patients. Endotoxins (EU/g) and Der p I levels were compared in the homes often asthmatic and ten control children, aged 6‐16 years, living in Sao Paulo, Brazil. The houses were visited once a month from February 1993 lo February 1994 and dust samples were collected from the bedding and floor of each subjects house. No significant differences were observed in ET and Derp 1 levels in the homes of asthmatics and controls. The highest ET levels were detected in January and November, whereas the lowest levels were detected in April and August (p < 0.05). demonstrating a distinct seasonal distribution. The highest Der p I levels in bedding were observed in July and the lowest in February (p < 0.05). while Derp I levels in floor did not show significant differences throughout the year. Symptom and medication scores were evaluated monthly in the group of asthmatic children. There was a significant correlation (p < 0.05. r = 0.63) between clinical symptom scores and ET exposure, however no significant correlation was found for mite exposure (p > 0.05. r = 0.19). The results suggest that ET exposure exacerbates asthmatic symptoms in mite allergic, asthmatic children.

Exposure and sensitization to dust mite allergens among asthmatic children in Sao Paulo, Brazil

A group of 20 mite allergic asthmatic children aged 6‐12 years old. living in Sao Paulo, Brazil, was studied regarding their degree of sensitization to house dust mites and exposure to mite allergens in their homes. In 18 out of 20 houses at least one dust sample was obtained which contained > 10 μg Der p I/g of dust. The highest levels of Dermatophagoides pteronyssinm allergens, Der p I and Group II, were measured in bedding samples (geometric mean 38.4 and 36.6 μg/g, respectively), followed by bedroom floor, TV room and kitchen. Mite allergen levels in Brazilian houses were as high as those reported to be associated with sensitization and acute attacks of asthma in other parts of the world. In keeping with previous reports that D. farinae is rarely found in Brazil, Der fl was undetectable or found in very low levels (<0.5 μg/g). Levels of cat allergen Pel d I of > 8 μg/g of dust were obtained only in 2 houses only. Cockroach allergen Bia g I was detected in five out of 20 houses. Levels of IgE antibodies to D. pteronyssinus were > 200 RAST U/ml in 19 out of 20 children (geometric mean 1588 RAST U/ml). IgE antibodies to cat, cockroach, A. fumigatus, ragweed and rye grass pollens were undetectable or <80 RAST U/ml. IgE antibodies to the mite Blomia tropicalix were also measured, and levels >200 RAST U/ml were observed in 13 out of 20 sera. Immunoabsorption studies demonstrated that the bulk of the IgE‐ antibody to B. tropicafis (64%) was to species‐specific allergens and that 36% were cross‐reactive with D. pteronyssinus. The implication of our results is that management of children with asthma in São Paulo should include skin testing for allergy to both Dermatophagoides and B. tropicalis as well as recommendations about environmental control of house dust mite exposure.

Chicken serum albumin (Gal d 5) is a partially heat-labile inhalant and food allergen implicated in the bird-egg syndrome*

Background: Chicken serum albumin (α‐livetin) has been implicated as the causative allergen of the bird‐egg syndrome. However, the clinical relevance of sensitization to this allergen has not been confirmed by specific challenge tests and environmental sampling. We investigated whether chicken albumin can be detected in air samples collected in a home with birds, and whether sensitization to this protein may cause respiratory and food allergy symptoms. The heat resistance of chicken albumin and the possible cross‐reactivity with conalbumin were also investigated.

Serum IgE and human immunodeficiency virus (HIV) infection

Human immunodeficiency virus infection is characterized by a progressive depletion of helper T-lymphocytes and, like allergic diseases, is associated with altered T cell regulation. Total serum IgE was measured in 67 infected male subjects, 27 uninfected heterosexual male subjects, and 18 uninfected homosexual male subjects. The mean IgE level (132 IU/ml) of infected subjects with a helper T-lymphocyte number less than or equal to 200/mm3 was significantly greater than mean IgE levels of the uninfected heterosexual (38 IU/ml) and homosexual (35 IU/ml) groups. IgE levels were inversely related to both helper T cell and suppressor/cytotoxic T cell numbers but not to IgG or IgA levels. The increase in IgE was not a reflection of an increased prevalence of atopic disease (allergic asthma, allergic rhinitis, or atopic dermatitis) in the infected subjects. The elevation of IgE may be related to a difference among the groups in T cell production of IgE regulatory lymphokines.

Allergen-specific IgE levels and mite allergen exposure in children with acute asthma first seen in an emergency department and in nonasthmatic control subjects.

BACKGROUND Sensitization to allergens has been shown to be a risk factor for adults with acute asthma first seen in the emergency department. OBJECTIVE The purpose of this study was to evaluate the prevalence of specific IgE to common aeroallergens in children with asthma first seen in the emergency department and in control subjects. METHODS Fifty-four children, aged 3 to 16 years (mean age, 8.34 years) who visited the emergency department for treatment of acute bronchospasm or other illness, were evaluated. Specific IgE to seven common aeroallergens and four common storage mites was determined. Group I consisted of 29 patients who had acute bronchospasm and histories of recurrent asthma. Group II consisted of 25 control subjects who had no clinical history of atopic disease. Group I and II were compared for differences in the prevalence of positive RAST responses to the 11 allergens tested. Dust samples were collected from 17 homes of subjects in group I and from 13 homes of subjects in group II and were analyzed for levels of Der p 1 and Der f 1. RESULTS Statistically significant differences in the prevalence of positive RAST results between groups I and II were found in response to: Dermatophagoides pteronyssinus, 89.6% versus 36% (p = 0.0001); Blattella germanica, 45.8% versus 9.5% (p = 0.018); Alternaria tenuis, 44.8% versus 4% (p = 0.001); and the storage mites Aleuroglyphus ovatus, 39.2% versus 4% (p = 0.002); Blomia tropicalis, 42.8% versus 0% (p = 0.0002); Chortoglyphus arcuatus, 46.4% versus 0% (p = 0.0001); and Lepidoglyphus destructor, 32.1% versus 0% (p = 0.0019). Mean specific IgE levels, expressed as percent of the total counts bound, were significantly higher in group I compared with group II only in response to D. pteronyssinus, 21.9% versus 2.1% (mean percent of total counts bound) (p = 0.0001). Analysis of dust samples revealed no significant differences between the two groups, except for a higher concentration of Der f 1 in the sofas of subjects in group II. CONCLUSION Sensitization to D. pteronyssinus, storage mites, and, to a lesser extent, to A. tenuis and B. germanica is associated with acute childhood asthma that requires emergency treatment in Florida.

Mite fauna, Der p I, Der f I and Blomia tropicalis allergen levels in a tropical environment

Fifty dust samples were collected from the mattresses and bedroom floors of 25 subjects with allergic asthma in Cartagena, Colombia, in order to identify house dust mites and quantitate Der p I, Derf I and Blomia tropicalis allergens. The geometric mean of the total mite density per gram of dust was 418 (range, 40–2280). Twenty‐two samples (44%) had more than 500 mites and four, less than 100. B. tropicalis and Dermatopha‐goides pteronyssinus were found in 96% and 90% of the samples, accounting for 40.1% and 35.7% of the total mites, respectively. Cheyletus malaccensis, Chortoglyphus arcuatus, Pyroglyphus africanus, Orihatids, Grallacheles bakeri. Tarsonemus spp., Suidasia spp., Dermatophagoides farinae and unidentified mites accounted for the rest. The geometric mean of the total mites/gram of dust in mattresses (563.9) was significantly higher than in floor dust (309. 1), P < 0.01. Allergen concentrations and mite numbers were analysed by Spearman rank correlations: B. tropicalis mites vs B. tropicalis allergen, r= 0.54, P<0.001; D. pteronyssinus mites vs Der p I, r= 0.52, P< 0.001. A negative correlation was obtained between B. tropicalis mites and Der p I. Allergens derived from B. tropicalis and other domestic mite species may play an important role in sensitization and allergic symptoms in Cartagena, Colombia.

Allergenicity of the mite, Blomia tropicalis.

BACKGROUND Blomia tropicalis (BT) occurs in a significant percentage of homes in tropical and subtropical geographic regions of the United States and Europe and in countries in South America and Asia along with the pyroglyphid mites, Euroglyphus maynei (EM), Dermatophagoides pteronyssinus, and D. farinae. Blomia species may be major sources of allergens in house dust in addition to Dermatophagoides species and E. maynei. METHODS Crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis were used to identify the antigens and allergens of BT and to determine the cross-reactivity between BT and the house dust mites, D. farinae, D. pteronyssinus, and the stored product mite, Tyrophagus putrescentiae. RESULTS Homologous crossed immunoelectrophoresis of BT resulted in 27 antigen-antibody complexes. Crossed radioimmunoelectrophoresis of these gels showed 21 different immunoglobulin E binding antigens when they were incubated in the sera from 14 patients with asthma whose radioallergosorbent test and skin test results were positive. Heterologous crossed immunoelectrophoresis reactions with BT and rabbit D. farinae body and feces, D. pteronyssinus body and feces, and T. putrescentiae body and feces antisera resulted in one to four precipitin lines. BT extract, reacted with rabbit antisera produced against the bodies of D. farinae, D. pteronyssinus, and T. putrescentiae, produced 3, 2, and 4 antigenic peaks, respectively; whereas crossed radioimmunoelectrophoresis of these gels with the sera of the 14 patients with asthma resulted in immunoglobulin E binding to 2, 2, and 4 peaks, respectively. CONCLUSIONS The results of this study indicated that BT contained multiple allergens of which most were species-specific. There was a limited amount of cross-reactivity between BT and the two common house dust mite species and the stored product mite. The amount of cross-reactivity appears to parallel the phylogenetic relatedness.

Mite-contaminated foods as a cause of anaphylaxis

BACKGROUND Although insect and arthropod contamination of certain foods has been recognized for many years, allergic manifestations caused by ingestion of mite allergens have only rarely been reported. OBJECTIVE The purpose of this study is to present clinical observations in patients who experienced acute anaphylaxis after eating mite-contaminated foods. METHODS Thirty atopic subjects who were first seen with systemic anaphylaxis precipitated by the ingestion of wheat-containing foods underwent skin prick tests with inhalant and food extracts, as well as with uncontaminated and mite-contaminated wheat flour. Flour samples were examined microscopically for identification and counting of mites. Der p 1 and Der f 1 levels were quantitated by using immunochemical methods. RESULTS The most common symptoms were breathlessness, angioedema, wheezing, and rhinorrhea, which started between 10 and 240 minutes after eating. Abundant mites were present in the flour obtained from 28 patients; Suidasia spp. mites were found in grated bread from the other two patients. Positive prick test responses to Dermatophagoides farinae-and mite-contaminated flour and negative skin test responses to wheat extract, other food extracts, and uncontaminated wheat flour were found in all patients. Skin test responses were positive in volunteers with mite allergy even after heating the mite-contaminated flour at 100 degrees C. Screening of 35 unselected flour samples demonstrated the presence of mites in 13 of them (37.1%). CONCLUSIONS Systemic anaphylaxis can occur after the ingestion of heated or unheated mite-contaminated foods. This problem may be more prevalent in tropical and subtropical countries than previously recognized.

Identification of Der p 23, a Peritrophin-like Protein, as a New Major Dermatophagoides pteronyssinus Allergen Associated with the Peritrophic Matrix of Mite Fecal Pellets

The house dust mite (HDM) Dermatophagoides pteronyssinus is one of most important allergen sources and a major elicitor of allergic asthma. We screened a D. pteronyssinus expression cDNA library with IgE Abs from HDM allergic patients. A cDNA coding for a new major allergen was isolated, which showed sequence homology to peritrophins, which contain chitin-binding domains and are part of the peritrophic matrix lining the gut of arthropods. The mature Der p 23 allergen was expressed in Escherichia coli as an 8-kDa protein without its hydrophobic leader sequence and purified to homogeneity. It reacted with IgE Abs from 74% of D. pteronyssinus allergic patients (n = 347) at levels comparable to the two major HDM allergens, Der p 1 and Der p 2. Thus, Der p 23 represents a new major D. pteronyssinus allergen. Furthermore, rDer p 23 exhibited high allergenic activity as demonstrated by upregulation of CD203c expression on basophils from D. pteronyssinus allergic patients. Immunogold electron microscopy localized the allergen in the peritrophic matrix lining the midgut of D. pteronyssinus as well as on the surface of the fecal pellets. Thus, we identified a new major D. pteronyssinus allergen as peritrophin-like protein. The high allergenic activity of Der p 23 and its frequent recognition as respiratory allergen may be explained by the fact that it becomes airborne and respirable through its association with mite feces. Der p 23 may be an essential component for diagnosis and specific immunotherapy of HDM allergy.

Identification and purification of an important cross-reactive allergen from American (Periplaneta americana) and German (Blattella germanica) cockroach

Aqueous whole body extracts from two major domiciliary cockroaches, the American, Periplaneta americana, and the German, Blattella germanica, were analyzed in crossed immunoelectrophoresis and immunoblotting. Forty-five antigens were found in P. americana and 29 in B. germanica. IgE-binding antigens were identified by crossed radioimmunoelectrophoresis with sera from 30 cockroach-allergic patients. Seven and three precipitates from P. americana and B. germanica bound significant amounts of IgE. A cross-reactive, apparently homologous allergen, from P. americana and B. germanica bound IgE from 100% and 70%, respectively, of the patients. These important allergens were tentatively named Per a I and Bla g I. The allergens were purified by sequential ion exchange, gel filtration, and isoelectric focusing. Both allergens had a molecular size of 33 to 37 kd in Sephadex G-75 gel filtration, and 28 kd in high-performance liquid chromatography gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a minor band at approximately 25 kd, and most of the protein at 6 kd. The isoelectric point of both allergens was found be to 3.5. In amino acid analysis, the allergens were highly similar. Skin test revealed the allergens to be important in vivo sensitizing agents. The allergens may be used for environmental assays for cockroach exposure in the homes of allergic subjects.