Hindawi Publishing Corporation Clinical and Developmental Immunology Volume 2011, Article ID 302739, 11 pages doi:10.1155/2011/302739 Research Article Serum and Salivary IgE, IgA, and IgG 4 Antibodies to Dermatophagoides pteronyssinus and Its Major Allergens, Der p1 and Der p2, in Allergic and Nonallergic Children Diego O. Miranda, 1 Deise A. O. Silva, 1 Jorge F. C. Fernandes, 1 Meimei G. J. Queir ´ os, 1 Hamilton F. Chiba, 2 Leandro H. Ynoue, 1 Rafael O. Resende, 1 Janethe D. O. Pena, 3 Sun-Sang J. Sung, 4 Gesmar R. S. Segundo, 1 and Ernesto A. Taketomi 1 1 Laboratory of Allergy and Clinical Immunology, Institute of Biomedical Sciences, Federal University of Uberlˆ andia, Avenue Par´ a 1720, Campus Umuarama, 38400-902 Uberlˆ andia, MG, Brazil 2 Laboratory of Clinical Analysis, 280 Padre Felix Street, 75523-220 Itumbiara, GO, Brazil 3 Laboratory of Molecular Biology, Institute of Biomedical Sciences, Federal University of Uberlˆ andia, Avenue Par´ a 1720, Campus Umuarama, 38400-902 Uberlˆ andia, MG, Brazil 4 Center for Immunity, Inflammation and Regenerative Medicine, Department of Internal Medicine, Health Sciences Center, School of Medicine, University of Virginia, 22908-0395 Charlottesville, VA, USA Correspondence should be addressed to Gesmar R. S. Segundo, gesmar@bol.com.br Received 26 May 2011; Accepted 23 July 2011 Academic Editor: K. Blaser Copyright © 2011 Diego O. Miranda et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 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. 1. Introduction Allergic rhinitis (AR) is a global public health problem and it is gaining importance due to the rapid increase in its prevalence worldwide [1]. In Brazil, in a study using the International Study of Asthma and Allergies in Childhood (ISAAC), Sol´ e et al. [2] found an average prevalence of rhinitis from 25.7% in groups of children aged 6-7 years and 31.7% between adolescents aged 13-14. According to ARIA (allergic rhinitis and its impact on asthma), AR is clinically defined as an inflammation of the nasal mucosa, mediated by IgE after exposure to allergens, and the symptoms occur most frequently for two or more days for more than 1 hour [1, 3]. Recently, other allergen-specific antibodies such as IgG, IgG4, and IgA have been reported to be involved during the course of allergic diseases [4]. House dust mites (HDMs), especially Dermatophagoides pteronyssinus, are considered an important source for aller- gen sensitization and they are a major risk factor for allergic respiratory diseases in genetically predisposed patients [5]. Their allergens are divided into groups according to their biochemical composition, homology, and molecular weight. Nowadays, 20 allergens have been described for D. pteronyssi- nus [6]. The group 1 (Der p1, 25 kDa) allergens are located in high concentration in faecal pellets [7], while those of the group 2 (Der p2, 14 kDa) are most found in components of