Effect of praziquantel on certain immune responses of schistosomal Egyptian patients. I. Changes of specific immunoglobulins.

Specific antischistosomal IgG, IgM, and IgE were estimated by ELISA in 117 rural school students before specific treatment with praziquantel monthly for 3-4 months thereafter. IgG and IgM were estimated as percentage of bound antibodies. IgE was estimated by avidin-biotin ELISA (AB-ELISA) as IU/ml using a panel of known IgE standards. Soluble surface Schistosoma mansoni adult worm antigen was used for all estimates. Total IgE was estimated in a smaller group by an ELISA kit. The percentage of specific IgE was calculated. A group of endemic controls (22 students) and non-endemic controls (17 cases) were included. Statistical analysis of results showed the specific immunoglobulins to be significantly reduced 2 months after treatment of the schistosomal cases. These reduced levels, however, were still significantly higher than those of controls. The presence of early hepatosplenomegaly and the co-existence of other parasites had no significant influence on the results. No correlation could be established between the levels of specific antischistosomal IgG, M and E and the intensity of infection. The significance of these results is discussed.