title: Secretory IgA antibody responses in Venezuelan children infected with Giardia duodenalis.
abstract: We standardized and evaluated an ELISA technique for the detection of total and specific anti-Giardia duodenalis secretory IgA antibodies (sIgA). Samples of saliva and serum of 161 Venezuelan schoolchildren were analysed. After stool examination, 66 children were diagnosed to be infected with Giardia duodenalis, 22 with other protozoa, and 73 non-parasitized. The mean (+ 2 SD) values of secretory IgA in the non-parasitized group was considered as the criterion of positivity. The levels of total and specific anti-Giardia sIgA were significantly higher in children with Giardia compared with the group with other protozoa (p < 0.01) and the non-parasitized group (p < 0.001). The ELISA technique developed showed values of sensitivity and specificity of 74 and 94 per cent, respectively, a predictive value of 92 per cent for positive samples and 80 per cent for negative samples. Specific anti-Giardia IgA serum levels showed a low sensitivity (57 per cent) and a predictive value for negative samples (53 per cent). Our results suggest that secretory anti-Giardia IgA levels measured in saliva samples may reflect local intestinal IgA responses elicited by these parasites. Thus, determinations of the levels of sIgA anti-Giardia could be a useful diagnostic tool for giardiasis in children.
authors.affiliation: Institute of Biomedicine, Faculty of Medicine, Central University of Venezuela, Venezuela. orquileo@hotmail.com
authors.forename: Orquídea L
authors.initials: OL
authors.lastname: Rodríguez
authors.forename: Isabel
authors.initials: I
authors.lastname: Hagel
authors.forename: Yovana
authors.initials: Y
authors.lastname: González
authors.forename: María Elena
authors.initials: ME
authors.lastname: Roque
authors.forename: Nelson
authors.initials: N
authors.lastname: Vásquez
authors.forename: Elianska
authors.initials: E
authors.lastname: López
authors.forename: María Cristina
authors.initials: MC
authors.lastname: Di Prisco
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood* / Q000302:isolation & purification; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000469:parasitology; D016829:Giardia lamblia / Q000276:immunology*; D005873:Giardiasis / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000302:isolation & purification*; D012463:Saliva; D012680:Sensitivity and Specificity; D014687:Venezuela / Q000453:epidemiology
chemical_list: D000913:Antibodies, Protozoan; D007071:Immunoglobulin A, Secretory