Saliva and sera IgA and IgG in Egyptian Giardia-infected children

Abstract

Giardiasis is a gastrointestinal infection of wide distribution that is more prevalent in childhood. Easy and rapid diagnosis of giardiasis is essential for reduction of this infection. This cross-sectional study included 62 children in which collection of saliva, stool and serum samples was performed. An enzyme-linked immunosorbent assay (ELISA) technique was evaluated to detect IgA and IgG responses in both saliva and serum samples. Twenty-two children were positive for Giardia duodenalis infection by direct examination of faecal specimens, 20 non-infected and 20 infected with other parasites. Salivary and serum IgA and IgG responses against G. duodenalis infection were significantly higher in Giardia parasitized than non-Giardia parasitized children (p < 0.001). This concludes that specific salivary IgA may serve as a diagnostic tool and specific salivary IgG as a screening tool in monitoring the exposure of various populations to Giardia duodenalis. The advantage of salivary assays over serum immunoglobulin assay is being easy and non-invasive in sampling technique which is important especially for young children.

Specific IgG and IgA Antibody Reactivities in Sera of Children by Enzyme-Linked Immunoassay and Comparison With Giardia duodenalis Diagnosis in Feces

“…Studies have suggested that anti-Giardia IgA antibody is a better indicator of current infection than IgG, since it is predominantly produced in the gastrointestinal tract [15,16]. However, the seroprevalence of IgA in our study was higher than that of IgG (23.6% vs. 13.9%).…”

“…The considerable frequency of G. duodenalis and other protozoa observed in this study may be explained, in part, by the small size of the cysts, which facilitates their passage through filters and enables their escape from the standard processes of water treatment, in addition to the poor hygiene habits and immune defense immaturity of children [29]. Experimental, clinical, and epidemiological observations indicate that G. duodenalis stimulates an immune response in the host [30,31], and anti-Giardia antibodies have been detected in individuals with G. duodenalis infection [15,16]. Based on these findings, serological tests were developed to detect specific IgG, IgM, and IgA in the serum of patients.…”

“…In our study, the ELISA for anti-G. duodenalis IgG and IgA showed a sensitivity of 80% and a specificity of 90% and 83.3%, respectively. Previous studies have found sensitivities ranging from 64-97% and specificities from 84-85% in anti-Giardia IgG ELISA [12,16]. These differences are possibly due to the different populations studied, stage of infection, or technical variations in the immunoassays.…”

Host defences against Giardia lamblia

“…The protective and clearance capacity of IgA during giardiasis has been investigated. Anti‐ Giardia secretory IgA can be detected in human saliva and breast milk . Mice deficient in antibody production, mainly of type IgA, fail to eliminate G. muris and G. lamblia .…”

“…Salivary (IgA) and serum (IgG) responses against G. duodenalis infection were significantly higher in infected patients than in controls. This observation could lead to the development of a diagnostic tool that measures specific salivary IgA and specific serum IgG antibodies to monitor the exposure of various populations to G. duodenalis . Therefore, B cells and especially IgA antibodies are important but not strictly required for the control of Giardia infections.…”