Early Exposure to Respiratory Allergens by Placental Transfer and Breastfeeding.

The relationship between allergen exposure and the onset of or protection from allergic diseases remains unclear. Many factors could be related to immunological responses, such as the age when the exposure occurs, type of allergen, timing, dose, and allergen route. In this study, we investigated whether exposure to respiratory allergens could occur in pregnancy or early life. In particular, we assessed whether Der p 1 and Blo t 5, as well as specific antibodies against these allergens, could be detected in 90 paired cord blood and colostrum samples. Der p 1 was detected in 58.6% of colostrum and 29% of cord blood samples, whereas Blot 5 was positive in 41.3% and 9.6% of the samples, respectively. Similar to specific IgA, which could be detected in all samples for both mites, specific IgG was found in a high number of colostrum samples, 93.5% and 94.8% for Dp and Bt, respectively. Although allergens were not detected in all cord blood samples, a high percentage of them (≥95%) were positive for specific IgM to both mites in cord blood samples, suggesting that neonates can be exposed and sensitized to airborne allergens during pregnancy. Many studies have attempted to correlate allergen exposure or its prevention in early infancy with the onset of or protection from allergic diseases. However, conflicting and inconsistent data do not show a clear correlation with or suggest a way to prevent allergen sensitization. Nevertheless, these unconvincing results could be better understood if the relationship with many aspects of allergen exposure after pregnancy could be clarified. Thus, it is necessary to address basic issues related to allergen exposure, including the development of reproducible, standardized and reliable methods, and to determine how and where the exposure occurs.

Modulation of mucosal/systemic antibody response after sublingual immunotherapy in mite-allergic children.

BACKGROUND: There have been no data on sublingual immunotherapy (SLIT) in Brazilian patients sensitized to house dust mites. This study aimed to evaluate the mucosal/systemic antibody response changes and clinical efficacy after SLIT using Dermatophagoides pteronyssinus (Dpt) allergens with or without bacterial extracts in mite-allergic Brazilian children. METHODS: Patients with allergic rhinitis and asthma were selected for a double-blind, placebo-controlled trial randomized to three groups: DPT (Dpt extract, n = 34), DPT+MRB (Dpt plus mixed respiratory bacterial extracts, n = 36), and Placebo (n = 32). Total symptom and medication scores for rhinitis/asthma, skin prick test (SPT) to Dpt, and measurements of Dpt-, Der p 1-, Der p 2-specific serum IgE, IgG4, IgG1, and specific salivary IgA were evaluated at baseline and after 12 and 18 months of treatment. RESULTS: A significant long-term decline in total symptom/medication scores was observed only in active groups (DTP and DPT+MRB). There was no significant change in SPT results in all groups. SLIT using Dpt allergen alone induced increased levels of serum IgG4 to Dpt, Der p 1, and Der p 2, serum IgG1 and salivary IgA to Dpt and Der p 1. SLIT with Dpt plus bacterial extracts was able to decrease IgE levels, particularly to Der p 2, to increase salivary IgA levels to Der p 1, but had no changes on specific IgG4 and IgG1 levels. CONCLUSIONS: All children undergoing SLIT showed clinical improvement, but a long-term reduction in symptom/medication scores with modulation of mucosal/systemic antibody responses were seen only in active groups (DPT and DPT+MRB).

Serum and salivary IgE, IgA, and IgG4 antibodies to Dermatophagoides pteronyssinus and its major allergens, Der p1 and Der p2, in allergic and nonallergic children.

Allergic rhinitis (AR) is a public health problem with high prevalence worldwide. We evaluated levels of specific IgE, IgA, and IgG4 antibodies to the Dermatophagoides pteronyssinus (Dpt) house dust mite and to its major allergens (Der p1 and Der p2) in serum and saliva samples from allergic and nonallergic children. A total of 86 children were analyzed, from which 72 had AR and 14 were nonallergic healthy children. Serum IgE and serum/salivary IgG4 levels to Dpt, Der p1, and Der p2 were higher in allergic children whereas serum/salivary IgA levels to all allergens were higher in nonallergic children. IgE levels positively correlated with IgG4 and IgA to all allergens in allergic children, while IgA levels negatively correlated with IgG4 to Dpt and Der p1 in nonallergic children. In conclusion, mite-specific IgA antibodies predominate in the serum and saliva of nonallergic children whereas mite-specific IgE and IgG4 are prevalent in allergic children. The presence of specific IgA appears to have a key role for the healthy immune response to mucosal allergens. Also, specific IgA measurements in serum and/or saliva may be useful for monitoring activation of tolerance-inducing mechanisms during allergen specific immunotherapeutic procedures, especially sublingual immunotherapy.

Antibody and cytokine responses to house dust mite allergens and Toxoplasma gondii antigens in atopic and non-atopic Brazilian subjects.

According to hygiene hypothesis, a lower exposure to infection is associated with increased prevalence of allergic diseases. This study aimed to investigate the association between atopy and Toxoplasma gondii (Tg) infection by analyzing the antibody and cytokine responses to house dust mite allergens and T. gondii antigens in Brazilian subjects. A total of 275 individuals were assessed and divided into atopics (n=129) and non-atopics (n=146) based on markers of allergy (positive skin prick test and ELISA-IgE to mite allergens) or Tg-seropositive (n=116) and Tg-seronegative (n=159) groups according to infection markers (positive ELISA-IgG to T. gondii). Tg-seropositive individuals presented lower allergenic sensitization (37%) to mite allergens than Tg-seronegative subjects (54%). A significant association was found between atopy and negative serology to T. gondii (OR: 2.0; 95% CI: 1.23-3.26; P<0.05). Proliferative responses and cytokine production after antigenic stimulation showed predominant synthesis of Th1-cytokines as IFN-gamma in Tg-seropositive patients, whether atopics or non-atopics. Conversely, Th2-cytokines as IL-5 prevailed in atopics compared to non-atopics, regardless the seropositivity to T. gondii. Levels of IL-10, IL-13, IL-17, and TGF-beta were not able to discriminate the groups. Hence, a negative association between atopy and infection by T. gondii was demonstrated for the first time in Brazilian subjects, focusing on the antibody and cytokine responses and indicating that the immunomodulation induced by the parasite may play a protective role in the development of allergic diseases.

Heterogeneidade da resposta de anticorpos IgE aos alérgenos principais de Dermatophagoides pteronyssinus entre pacientes com alergia respiratória: Implicações para a imunoterapia específica com alérgenos / Heterogeneity of the IgE antibody response to major allergens from Dermatophagoides pteronyssinus among patients with respiratory allergy: Implications for allergen-specific immunotherapy

Objetivo: Analisar os níveis de IgE sérica específica aos alérgenos Der p 1 e Der p 2 de Dermatophagoides pteronyssinus (Dpt) em pacientes com alergia respiratória e comparar com as sensibilizações in vivo (teste cutâneo de puntura - TCP) e in vitro (ELISA- IgE) ao extrato total de Dpt. Métodos: Um total de 73 pacientes atópicos apresentando rinite alérgica com ou sem asma moderada e TCP positivo ao extrato total de Dpt foram estudados. Trinta indivíduos saudáveis com TCP negativo a ácaros da poeira domiciliar foram incluídos como controles. Níveis de IgE total e IgE específica a Dpt, Der p 1 e Der p 2 foram determinados por ELISA em pacientes atópicos (TCP+) e indivíduos controles não atópicos (TCP-). Resultados: Dos 73 pacientes atópicos, 38 (52 por cento) foram IgE duplo positivos aos alérgenos Der p 1 e Der p 2 (Der p 1+/Der p 2+), 11 (15 por cento) foram IgE positivos somente para Der p 1 (Der p 1+/Der p 2–), 7 (10po9r cento) foram IgE positivos somente para Der p 2 (Der p 1–/Der p 2+) e 17 (23 por cento) foram IgE duplo negativos para ambos alérgenos (Der p 1–/Der p 2–). Correlações significativas foram encontradas entre os níveis de IgE anti-Dpt e seus alérgenos (Der p1 ou Der p 2) bem como entre IgE anti-Der p 1 e anti-Der p 2 (P < 0,0001), mas não entre IgE específica a Dpt, Der p 1 ou Der p 2 e resultados do TCP. Pacientes com IgE duplo negativos apresentaram níveis de IgE anti-Dpt (IE = 1,4 ± 0,9) significativamente menores que os outros grupos, embora com altos níveis médios de IgE sérica total e valores de TCP. Conclusões: Os pacientes com alergia respiratória que apresentaram TCP+ ao extrato Dpt mostraram grande heterogeneidade da resposta de anticorpos IgE aos alérgenos principais de D. pteronyssinus, particularmente Der p 1 e Der p 2 e portanto, a determinação desses anticorpos específicos pode ser de grande valia para indicação e/ou seguimento de pacientes sensibilizados a ácaros sob imunoterapia específica com alérgenos.