Does schistosomiasis play a role in the high sero prevalence of HCV antibody among Egyptians?

Many studies have demonstrated a very high prevalence of HCV antibodies among blood donors (BD) and chronic liver disease (CLD) patients in Egypt. This high prevalence might be attributed to cross reactivity between HCV antibodies and schistosome antibodies. We decided to study the association and cross serology between the presence of anti-HCV and Schistosomal infection among BD and CLD patients. Sera of blood donors and CLD patients were tested for anti-HCV by second generation ELISA. Antibodies to Schistosoma species were quantified by IHA test. Two tailed z score was used to detect significant difference. To test for cross reactivity between the two antibodies 20 BD and 20 CLD patients positive for both HCV-antibody and schistosome antibody were taken as controls. Another 20 samples also served as a control group; 10 of them seropositive for HCV only and 10 positive for IHA for schistosomiasis alone. All were subjected to: 1) RIBA-2 confirmatory test 2) Adsorption of schistosome antibodies using 100 microgram schistosome antigens per 100 microliters serum 3) Both HCV-ELISA-2 and RIBA-2 were checked after adsorption. The titre of schistosome antibodies in positive sera ranged from 1:128 to 1:1536. HCV seroprevalence was more pronounced among antischistosomal positive sera. This was seen in both BD and CLD patients where antischistosomal positive sera were at double risk to show positive HCV antibody. After adsorption of schistosome antibody, there was no change in reactivity of both ELISA-2 and RIBA-2. We conclude that HCV antibodies were significantly higher in schistosomal antibody positive Egyptians, there was no cross reactivity between the two antibodies and the high prevalence could be due to HCV transmission during anti-bilharzial parenteral therapy or due to depressed cell mediated immunity associated with schistosomal infection.