1Maklad S, 1El-Gendi A, 1Higazi F, 2Abdel Raoof M and 1El-Sheikh N.
1Microbiology and 2General Medicine Departments, Faculty of Medicine For Girls, Al - Azhar University.
It has been suggested that the clinical forms of schistosomiasis correlate with some immunoregulatory mechanisms at the cellular level. To examine this possibility, rectal tissue biopsies from patients with different intensity and severity of Schistosoma mansoni infection were studied. Low and high egg excreters as well as intestinal and hepatosplenic patients were assayed for the expression of interferon-g (IFN-g), interleukin-10 (IL-10) m RNA using in situ hybridization technique and cell surface intercellular adhesion molecule-1 (ICAM-1) expression using direct immunofluorescence technique. Although all patients showed elevated levels of IFN-g and ICAM-1 as compared to controls, yet high egg excreters and hepatosplenic patients revealed significantly higher levels than low egg excreters and intestinal patients respectively (P< 0.001). In contrast, IL-10 mRNA expression was downregulated in high egg excreters and hepatosplenic patients as compared to low egg excreters and intestinal patients (P<0.001). These data coincided with the manifestations that were detected by endoscopy (gastric erosions, ulcers and oesophageal varices), colonoscopy (hyperaemic, haemorrhagic, ulcerated mucosa or piles) and ultrasonography (hepatosplenomegaly, fibrotic or cirrotic liver and ascites). Positive correlation was found between infection intensity (egg count /gm stools) and both IFN -g (r= 0.466, P<0.001) and ICAM-1 (r=0.888, P<0.001), and between IFN-g and ICAM-1 (r=0.604, P<0.001) for intestinal and (r=0.448, P<0.001) for hepatosplenic patients. In conclusion, upregulation of both IFN-g and ICAM-1 together with the downregulation of IL-10 expression, could be used as useful markers of disease severity, to avoid endoscopy, colonoscopy and ultrasonography.