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.