Immunological indicators of morbidity in human schistosomiasis mansoni: role of vascular endothelial growth factor and anti-soluble egg antigen IgG4 in disease progression.

Based sonographic examinations of 90 schistosomiasis mansoni, they were divided into five groups: lightly infected, heavily infected, intestinal, early hepatosplenic and periportal fibrosis. Using ELISA, the levels of circulating vascular endothelial growth factor (VEGF) and anti-soluble egg antigen (SEA) IgG4 were measured in their sera. Compared to normal controls, VEGF levels were significantly raised in all schistosomiasis patients groups except lightly infected and intestinal patients were insignificantly elevated. The level of VEGF correlated with disease progression from lightly infected to periportal fibrosis patients. It also correlated with sonographic indicators of portal hypertension; presence of portosystemic collaterals, portal vein dilatation and splenomegaly. Serum IgG4 was significantly raised in only periportal fibrosis and portal hypertension patients. The results provided evidence that circulating levels of VEGF can serve as a new indicator of progression of schistosomiasis mansoni reflecting angiogenesis that regulates the granuloma and fibrosis development in liver while IgG4 seemed to be an indicator of only fibrosis development. Both are potential sensitive markers for effectiveness of treatment in periportal fibrosis patients. The understanding of the key role of VEGF in schistosomiasis mansoni pathogenesis may provide a new pharmacological target.