Schistosoma mansoni infection or soluble egg antigen immunization can reduce allergic airway diseases

Objective The aim of the study was to investigate the impact of Schistosoma mansoni infection and soluble egg antigen (SEA) immunization on allergic airway diseases and to study the involved immune-modulation mechanisms. Background Schistosomiasis and allergic airway diseases are common health problems that affect a wide range of population. Many studies showed that there is an inverse relationship between prevalence of Schistosoma and allergic airway diseases. Materials and methods The mice groups were either infected with S . mansoni or SEA immunized or noninfected. Airway allergy was induced in laboratory mice by ovalbumin. Thereafter, the degree of lung inflammation was determined by histopathology. Immune response was studied by immune-histochemical examination of regulatory T (T-reg), CD4+ and CD8+ cells, and serum antiovalbumin IgE level was determined by ELISA. Results The infected and immunized groups showed significant reduction in lung pathology, CD4+ cell infiltration of lungs and serum antiovalbumin IgE level than the control group. This was associated with a significant increase in the immune-suppressor T-reg cells and CD8+ cells infiltration of lungs. Conclusion S. mansoni infection or SEA immunization have downregulating effects on ovalbumin-induced experimental allergic airway diseases. These effects could be attributed to increased activation of T-reg cells and CD8+ cells, which downregulate the immune response.