Investigação sobre associação entre ácaros da poeira, atopia, manifestações alérgicas e infecções intestinais helmínticas. / Investigation beetween dust mites, atopy allergy and intestinal helminthic infections.
AUTOR(ES)
Joilson Ramos de Jesus
DATA DE PUBLICAÇÃO
2005
RESUMO
The role of dust mites in the determination of the clinical form of allergy has not been well established. Many records in the literature show negative association between helminth infections and allergy, however, these data are still controversial. In this study we investigated the role of B. tropicalis and D. pteronyssinus as agents of atopy and allergy and possible association between atopy, allergy and helminth infections in individuals of a low socioeconomic status population of Salvador-BA. The survey was carried out using the ISAAC phase I questionnaire. From 513 individuals interviewed, 300 volunteers attended to the field ambulatory. They were submitted to the prick test (SPT) for aeroallergens, blood collection for hematological analysis and ELISA for IgG4 anti-Ascaris lumbricoides and anti-B. tropicalis IgE detection. It was also carried out stool examination for intestinal helminthes. High prevalence of symptoms of allergic diseases(asthma and rhinitis) was found in this population. The prevalence of SPT reactivity to one or more of the tested allergens was 31,4%, being B. tropicalis the most frequently found aeroallergen (15,9%), followed by Dermatophagoides pteronyssinus (12,1%) and Periplaneta americana (7,9%). IgE anti-B. tropicalis was detected in 40,9% of the individuals. Levels of eosinophils above 4% and 10% were found in 78,1% and 36,2% of the studied population, respectively, without however being associated with allergy and atopy. Symptoms of asthma were directly associated with positive SPT for D. pteronyssinus and symptoms of recent rhinitis were associated with B. tropicalis positive SPT. The reactivity to B. tropicalis SPT was associated with the presence of anti-B. tropicalis IgE, however, there was not a strong correlation between them. Using these two atopy markers, it was identified four sub-groups of individuals in the studied population and performed a Western-blot assay for detection of anti- B. tropicalis IgE. It was verified that only the two sub-groups that were B. tropicalis-specific IgE positive in ELISA were also positive in the Western-blot. The majority of the bands detected in these two groups were similar; however, the group with positive SPT recognized more three bands which were absent in the sera of the SPT negative group. Intestinal helminth infections occurred in 34,9% of the individuals, being A. lumbricoides, Trichuris trichiura and ancylostomids the most prevalent helminthes in this population. Eosinophil levels higher than 10% occurred in 36,2% of the population and were directly associated with the presence of intestinal helminthes. In addition, only 15,5% of the individuals presented high A. lumbricoides load. The presence of parasitic infection markers (opg >2600; presence of IgG4 anti-Ascaris and eosinophils >10%) was inversely associated with positive SPT and IgE B. tropicalis-specific tested group (SPT+ IgE+) and directly associated with negative SPT and positive IgE B. tropicalis-specific (SPT- IgE+). Our data are in contrast to prior studies performed in Salvador that found D. pteronyssinus as the most important allergen and corroborate previous studies showing that B. tropicalis is one of the main aeroallergens of the tropical regions. In the studied population, the B. tropicalis specific serum IgE may be influenced by helminthes infections and might not be a good marker of the atopic state. The reduction on the TC reactivity for B. tropicalis and D. pteronyssinus during helminth infections indicates a probable immunemodulatory effect of these parasites on the allergic reactions.
ASSUNTO(S)
rinite asma alergia helmintos asthma ige rhinitis imunologia helminthes allergy
