Idiotype/anti-idiotype immunoregulatory network correlates with an improved clinical outcome of schistosomiasis mansoni in humans.

Anti-idiotypes (anti-Ids) have a potential role in the immune modulation of various diseases. To study the correlation of anti-Ids with schistosomiasis mansoni morbidity, ELISA using polyclonal idiotypes (Ids) was used to determine the presence of anti-Ids in sera of 69 patients susceptible and resistant to reinfection. Ids were purified against Soluble Worm Antigen (SWAP) from sera of New Zealand white rabbits immunized with SWAP. The results showed that anti-Ids were detected in 15 (40.5%) of susceptible and 21 (65.6%) of resistant patients. Correlation of intensity of infection with age revealed an inverse relationship in patients positive for anti-Ids (regression coefficient beta = -0.47, p < 0.05) and contrarily, a direct relationship in patients negative for anti-Ids (beta = 0.67, p < 0.001). In addition, there was a direct association between the presence of anti-Ids and the lack of schistosome-related symptoms (chi2 = 3.6, p < 0.05) and hepatomegaly (chi2 = 9.4, p < 0.01). Moreover, comparison of patients positive and negative for anti-Ids revealed that those negative for anti-Ids were more vulnerable to develop symptoms (3.7 times) and hepatomegaly (8.1 times). In conclusion, the study further confirms the role of Id/anti-Id regulatory network as an important participant in the assortment of an improved clinical outcome of schistosomiasis. This may help to formulate a better understanding of the mechanisms of protective immunity in humans and provide perspective for the development of a future vaccine.