Association of Schistosoma mansoni-Specific IgG and IgE Antibody Production and Clinical Schistosomiasis Status in a Rural Area of Minas Gerais, Brazil

Abstract

BackgroundStudies in murine models and human populations have indicated that the collagen-rich granulomatous response against parasite eggs trapped in the liver is associated with the development of severe hepatosplenic schistosomiasis, characterized by periportal fibrosis and portal hypertension. The role of the humoral response in parasite susceptibility has been well established, but its participation in disease severity remains poorly understood. In this work, we evaluated the relationship between parasite-reactive IgE and IgG levels and schistosomiasis morbidity in infected patients with similar parasite burdens.Methodology/Principal FindingsNinety-seven Schistosoma mansoni-infected individuals were subjected to clinical examination and abdominal ultrasound analysis. IgG reactivity and IgE concentration against Schistosoma mansoni soluble egg antigens (SEA) and adult worm antigen preparation (SWAP) were evaluated by ELISA assay. Multivariable linear regression models were used to evaluate the relationship between parasite-reactive antibodies and the co-variables investigated. The study population showed low parasite burden (median 30 eggs/g feces), constant re-infection, and signs of fibrosis was detected in more than 30% of individuals. Most infected individuals showed IgG reactivity, and the median concentrations of IgE anti-SEA and anti-SWAP antibodies were 1,870 and 1,375 ng/mL, respectively. There was no association between parasite burden and antibody response or any parameter of disease severity. However, IgG anti-SWAP level was positively associated with morbidity parameters, such as spleen size and thickness of portal vein at the entrance and secondary branch. In contrast, the data also revealed independent inverse correlations between concentration of parasite-reactive IgE and gallbladder wall thickness, a marker of fibrosis in schistosomiasis.Conclusions/SignificanceThe data indicate that IgG anti-SWAP is positively associated with severe schistosomiasis, independently of parasite burden, while high production of parasite-specific IgE is associated with mild disease in the human population. Antibody profiles are good correlates for schistosomiasis severity and could be tested as biomarkers of disease severity.

Schistosoma mansoni PCR+-infected individuals in the Sudan present elevated systemic levels of chemokines when compared to uninfected and egg+ cohorts

“…CXCL10 secretion is under the genetic control of IFN-γ, is up-regulated in Th1-type inflammatory processes [32] and is thought to be a marker for IFN-dominated responses [33]. Negrao-Correa [36] investigated S. mansoni -infected individuals who were subjected to clinical examination and abdominal ultrasound analysis. Interestingly, an earlier study on S. mansoni has shown that the probability of reinfection increases in proportion with schistosomulae-specific IgG2 levels after therapy [35].…”

Morbidity Associated with Schistosomiasis Before and After Treatment in Young Children in Rusinga Island, Western Kenya

“…The major tool for assessing S. mansoni infection-associated morbidity in older patients is ultrasound [22][23][24][25][26][27][28] using the WHOrecommended Niamey scoring system. 29,30 It includes assessment of expected morbidities such as splenomegaly and left lobe hepatomegaly, as well as successively more pronounced liver ultrasound changes scored as image patterns (IP) A (normal), B ("starry sky," abnormal linear opacities of unclear significance), and C through F (progressive hepatic fibrosis).…”

Tandem repeat recombinant proteins as potential antigens for the sero-diagnosis of Schistosoma mansoni infection

“…IgG4 subtypes in human and IgG1 in mouse are involved in resistance and susceptibility to schistosomiasis [58,59] and thus are of great interest for the diagnosis of helminthic diseases [60].…”

“…We accordingly attempted to analyze the IgG subtypes raised against these antigens, as well as detecting specific IgE antibody, an important immunoglobulin during helminthic infections, including schistosomiasis [59]. The IgG1 subtype was found to be the dominant IgG response to the recombinant antigens (Fig.…”