The Presence of Anti-Idiotype Antibodies Inversely Correlates with Morbidity of the Disease in Schistosoma mansoni Infected Children.

¹Kamal SH, ²Maklad SS, ²Higazi FF, ¹El-Nagaar MB and 1El-Sheikh NA.

¹Pediateric and ²Microbiology Departments, Faculty of Medicine For Girls, Al- Azhar University, Cairo, Egypt.

Idiotypic/anti-idiotypic (Id/anti-Id) interactions have been reported in human schistosomiasis. The nature of their role in S. mansoni infection is a controversy. The presence of circulating anti-Id antibodies (Ab₂) in active, reinfected children and adolescents with S. mansoni (n=30) and formerly treated, resistant to reinfection (n=26) schistosomal patients was examined and correlated with the intensity of infection and morbidity of the disease. Affinity purified polyclonal Id antibodies (Ab₁) to soluble worm antigen (SWAP) were prepared in hamsters and used to capture anti-Id (Ab₂) antibodies in patients plasma using ELISA. The results revealed that patients with Ab₂ reactivity were more frequent in the former group than in the active group (P<0.001). However, both groups had significantly higher Ab₂ reactivity compared with controls (p <0.05, P< 0.001) respectively. Significant negative correlations were found between Ab₂ reactivity and both intensity of infection (egg count/gm stools), and morbidity of the disease (S. mansoni related symptoms and hepatomegaly) P<0.001 for both. In conclusion, the present study provides an evidence on the existence of anti - Id antibodies (Ab₂) in the circulation of S. mansoni infected children and suggests a role for these Id/anti - Id interactions in the immunopathology as well as regulation of the protective immune response.