Comparison of serum antibody responses to Giardia lamblia of symptomatic and asymptomatic patients.

Abstract

The circulating anti-parasite antibody response against Giardia lamblia in symptomatic and asymptomatic Egyptian children with confirmed giardiasis was examined. Symptomatic patients were identified using the following criteria: presence of only G. lamblia cysts in the feces, and one or more of the following symptoms, diarrhea, abdominal pain, loss of weight, vomiting and/or nausea, and abdominal distention. The anti-parasite humoral response was measured using indirect immunofluorescence (IFA), ELISA, and immunoblotting. There was a significant difference in the anti-parasite antibody response measured by IFA of asymptomatic and symptomatic patients, in which more than 34% of the asymptomatic patients had a titer equal to or less than 1:500, and more that 29% of the symptomatic patients had a titer of 1:8,000 or higher. The circulating anti-parasite total IgM and IgA but not IgG, measured by ELISA, was significantly higher in symptomatic than in asymptomatic patients, and were related to higher cyst output observed in symptomatic individuals. Although total anti-parasite IgG response was similar in symptomatic and asymptomatic patients, the analysis of the IgG isotype responses revealed that both IgG1 and IgG3 were significantly higher in symptomatic patients. The antigen recognition by anti-parasite IgM, IgA, IgG1, and IgG3 of symptomatic and asymptomatic individuals, determined by immunoblotting, was heterogeneous and revealed only minor differences in the response of the two groups.

Immune Response to Giardia duodenalis

“…Saliva samples taken from giardiasis patients showed 24 antigen bands with molecular masses varying between 14 and 170 kDa (161). Only one study reported 100% sensitivity of the ELISA, IFA, or Western blot technique in detecting specific antibodies in persons with proven cases of giardiasis (172). The investigators reported a significantly higher titer of circulating antibodies in symptomatic patients than in asymptomatic patients; these results confirmed the results of an earlier study (176).…”

Antibody Response in Children Infected with Giardia intestinalis before and after Treatment with Secnidazole

“…16 In addition, detection of specific protein bands and serum antibody responses against Giardia species proteins by Western blotting and ELISA has been reported. 6,7,[17][18][19][20][21] Nevertheless, little is known about effect of treatment on specific antibody responses.…”

Effects of asymptomatic Giardia intestinalis infection on carbohydrate absorption in well-nourished Mexican children.

“…7 The presence or absence of symptoms has been related to the strain of G. intestinalis, 8,9 to the severity of the infection, 10 or to the immune status of the host. [11][12][13] The potential consequences of asymptomatic giardiasis on nutrient absorption are particularly important in northwestern Mexico, where many children carry this parasite. However, few studies have focused on the potential effects of moderate or asymptomatic giardiasis on nutrient absorption, and thus its effects on the nutritional status of the host.…”