Prevalence of self-reported food allergy in Cartagena (Colombia) population.

BACKGROUND: Food allergy (FA) is an important health problem in western societies; however, there are no data available from developing countries. Studies based on self-reported symptoms range from 1.4 % to 33 %, and it is supposed that FA is more prevalent early in life. To our knowledge in Latin America there has not been a report on prevalence estimates for food allergy in unselected population-based studies. OBJECTIVES: The aim of this study was to determine the prevalence of self-reported food allergy, the most frequent symptoms, the allergens, and the risk factors for FA in a population from Cartagena (Colombia). METHODS: This is a cross-sectional study. A total of 3099 (55.4 % Female, and 44.6 % Male) individuals in a randomised selection, aged 1-83 years, living in neighbourhoods in Cartagena, were asked questions about personal and family history of allergies and food allergy. RESULTS: The overall prevalence of self-reported FA was 14.9 % (Total 461 subjects, 16.4 % female, 12.8 % male). Fruit/vegetables (41.8 %), seafood (26.6 %), and meats (20.8 %), were the most reported allergens. The most frequently reported symptoms were skin (61.4 %), gastrointestinal (29.1 %), and respiratory reactions (8.6 %). FA was most frequent in subjects reporting atopic diseases (62.9 % vs. 29.6 %, chi2 test, p < 0.001). CONCLUSIONS: Self-reported FA was determined in Cartagena population. Fruit/vegetables, seafood, and meats were the most reported allergens. Skin and gastrointestinal symptoms were the most frequent manifestation of FA. Our study is the first report on prevalence estimates for food allergy in a Latin American country.

Cloning and expression of complementary DNA coding for an allergen with common antibody-binding specificities with three allergens of the house dust mite Blomia tropicalis.

The mite Blomia tropicalis is a potent source of allergens in tropical and subtropical regions. So far, most of these allergens have only been studied by immunoblotting. To characterize them at the molecular level, a lambda gt11 complementary DNA library was constructed from messenger RNA isolated from whole B. tropicalis mites. This library was screened by using pooled sera from patients allergic to B. tropicalis in a plaque IgE radioimmunoassay. A B. tropicalis IgE-positive clone (Bt-M) was selected for immunologic studies. After subcloning into pBluescript (Stratagene, La Jolla, Calif.), it produced a sequence of 310 bp, with a probable amino acid sequence of 72 residues for the expressed peptide. The recombinant protein was transferred to nitrocellulose filters and probed with 100 sera from patients allergic to B. tropicalis. Forty-seven percent of sera reacted with the recombinant allergen. Immunoblottings performed with allergic serum and B. tropicalis-affinity-purified IgE demonstrated that the recombinant protein shares allergenic epitopes with the 11-13, 14, and 16 kd native allergens of B. tropicalis, which are known to be important allergens of this mite.

IgE antibodies to four mite allergens in atopics and non-atopics living in Barbados - abstract

The prevalence of specific IgE (RAST) to Blomia tropicalis (Bt) was evaluated for 64 individuals from four families residing in Barbados, with self-reported atopic asthma (AA) and/or self-reported allergic rhinitis (AR) or individuals with no reported atopic disease (NA). The presence of specific IgE antibodies that reacted with components of Chortoglyphus arcuatus (Ca), Dermatophagoides pteronyssinus (Dp) and Euroglyphus maynei (Em) was also evaluated; components from Ca, Dp and Em were separated by SDS-PAGE, transferred to nitrocellulose membranes and screened with sera from the 22 AAs, 17 ARs and 25 NAs. Total serum IgE was significantly higher in individuals with self-reported AA (logIgE = 977 ng/ml) than in individuals reporting no AA (logIgE = 323 ng/ml). There was a significant difference between the number of AAs who were Bt-positive according to RAST (68 percent) and the number of individuals without AA(p=0.002). IgE antibodies to Ch and Em were significantly higher in individuals with AA than in those without AA (p = 0.001 and p = 0.005, respectively), and there was a weak correlation between IgE antibodies to Dp and self-reported AA (p=0.05). A significant pattern of conversion of response to certain bands within families was observed (AU)

Sensitivity to blomia tropicalis among allergic individuals in Barbados - abstract

The prevalence of specific IgE (RAST) to tropical house dust mite Blomia tropicalis (Bt) was studied in 126 related individuals with self-reported atopic asthma (AA) and/or self-reported allergic rhinitis (AR) and individuals with no reported atopic disease. RAST results were considered positive when a serum bound > 5 percent of the total counts (percent TCB) added; 17 (65.4 percent) AA were positive to Bt, 7 (29.2 percent) AR without AA were positive to Bt, and 16 (21.9 percent) individuals reporting no AA or AR were positive to Bt. Total serum IgE was significantly higher in individuals with self-reported AA (750 ng/ml) than in individuals reporting no AA (282 ng/ml; Student's t test, p = 0.02). There was no association between total serum IgE and self-reported AR. Additionally, total IgE was weakly correlated with RAST (Bt) for all individuals (r=0.349, p=0.001). Subjects with self-reported AA had a significantly higher mean percentage TCB (19 + 17) than individuals without self-reported AA (10 + 14; Student's test, p<0.05). This study suggests that sensitivity to Bt is common in individuals with atopic asthma living in Barbados (AU)

HLA alleles in the population of Cartagena (Colombia).

It is known from historical records that the population of Cartagena (Colombia) is a mixture of caucasoids (Spaniards) and negroids (Africans) that is named mulattos. The present study was carried out to determine the distribution of HLA antigens in this population. A sample of 370 individuals was HLA serologically typed; 91 of them were typed for Complement alleles and 47 were DNA typed using PCR amplification and oligonucleotide probes for the HLA-DQA1 locus. The analysis of the allele and haplotype frequencies obtained, together with the genetic distances calculated with other populations, showed that most of the HLA genes of mulattos are from negroids and caucasoids. The Asian and Amerindian contribution is small, consistent with the historical and socioanthropological documentation. For example, A23, Aw34, Aw36 and Bw45, as well as DQA1*0101, DQA1*0301 and BfF have frequencies similar to that observed in negroids. In contrast, many significant differences were observed when comparing the antigen and allele frequencies of mulattos with that of Asians and Amerindians. Our results add evidence to the notion that the arrival of Spaniards in America 500 years ago established several racial mixtures. The HLA characterization of one of these, mulattos, will allow a better application of the HLA technology in the fields of basic research, organ transplantation and forensic medicine among this population.

Frequency of DPB1*0401 is significantly decreased in patients with allergic asthma in a mulatto population.

Allergic asthma (AA) is a multifactorial disease in which the IgE hyperresponsiveness to mite allergens is determinant for its pathogenesis and clinical picture. We have reported previously that IgE responsiveness to mite allergens in AA patients is linked to HLA and possibly controlled by a dominant suppression (Is) gene of that region. The present population study was done to detect alleles involved in the genetic control of mite IgE response that accompanies AA, using polymerase chain reaction and oligonucleotide DNA typing of DP locus. Instead of finding any significant positive association with AA, in this study we found that the allele DPB1*0401 is present mainly in the nonallergic control population and strikingly absent in patients (p less than 0.008), suggesting that this gene could confer resistance to AA and other atopic diseases. Our results add more evidence regarding the existence of Is genes in the HLA region involved in the control of IgE immune response to environmental allergens. Furthermore, they suggest that genes of HLA are important genetic components involved in the etiology of AA.