HUMORAL IMMUNE RESPONSE (IGG1, IGG4) FOR MONITORING THE EFFICACY OF PRAZIQUANTEL THERAPY IN SCHOOL CHILDREN (6-18 YEARS) INFECTED BY SCHISTOSOMA MANSONI
Samia E. Etewa1; Naglaa F. Abd El-Aal1; Maha Saber1; and Sherif M. Galal2
Departments of medical Parasitology1 and Tropical Medicine2, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Background: Schistosomiasis continues to be a significant public health problem. Several previous studies referred to into the possible relationship between immunoglobulin G (IgG) isotypes levels and the response to praziquantel (PZQ) therapy, demonstrating the participation of IgG1 and IgG4 in the response to S. mansoni infection, suggested that the assessment of IgG isotypes profiles may help to highlight the anti-parasite humoral immune response in humans infected by Schistosoma mansoni and subjected to PZQ treatment. Objective: The current study evaluates the specific anti-schistosomal IgG1 and IgG4 role in assessment of cure as well as for monitoring PZQ efficacy. Material and methods: 30 S. mansoni infected patients (school children), aged 6-18 years, selected from out patient clinics of Tropical Medicine Department in Zagazig University Hospitals. A group of 20 apparently healthy children free from schistosomiasis was considered a control group as a base line. Before treatment (BT) of infected children, stool samples from all children were examined by direct smear and Kato-technique methods for groups differentiation. Serum samples were collected from all children to measure anti- soluble egg antigen (SEA) IgG1 and IgG4 by enzyme linked immunosorbent assay (ELISA). The infected children were treated with single oral dose [40 mg/kg body weight (b.w)] of PZQ. Followed up by measuring anti- SEA IgG1 and IgG4 antibodies in their sera 2, 4 and 6 months after treatment (AT) by ELISA and stool egg count by direct smear and Kato-technique methods. Results: The obtained data showed that, the level of IgG1 was higher than IgG4 among infected children and both of them were significantly higher than control group. Two months after PZQ therapy, IgG1 level began to decrease and this decrease continued till six months AT. On the other hand IgG4 level was increasing two months AT then started to show significant decrease on the fourth month till sixth month AT. It was noticed that there was a positive correlation between the level of both IgG1 and IgG4 and the intensity of infection previously measured by kato-technique BT and AT. The sensitivity of ELISA in detection of anti-SEA IgG1 was 100%, and its specificity was 95% while its sensitivity in detecting anti-SEA IgG4 was 93.3% and its specificity was 90%. Conclusion: follow-up of the treated Schistosoma mansoni infection by measuring specific anti-schistosomal IgG1 and IgG4 is useful for assessment of cure as well as for monitoring PZQ efficacy.
December 2011