Evaluation of Schistosoma haematobium 27-29 kDa antigen for immunodiagnosis of schistosomiasis haematobium.

The study demonstrated the immunodiagnostic potential of differrent Egyptian human Schistosoma haematobium antigens. ELISA was used to measure the levels of total immunoglobulin G (IgG) and IgG4 antibodies (Abs) against S. haematobium adult worm antigens (Ags) (SAWA), excretory/secretory Ags (E/S) and cysteine proteinase Ag (27-29 kDa) for diagnosis of schistosomiasis. SDS-PAGE profiles of S. haematobium Ags showed several bands for SAWA, E/S and 27-29 kDa Ags which are characteristic of infections with Schistosoma spp. Purified protein fraction showed a single homogenous band of 27-29 kDa. For summarizing the potency of S. haematobium Ags, sensitivety rate, negative predictive value and diagnostic efficacy were calculated between data of 40 human patients in ELISA. SAWA Ag recorded 85.0 %, 77%, 90.0% with total IgG & 90.0 %, 83% and 93.3% with IgG4 isotype, respectively. While, E/S recorded 87.5%, 80%, 92.0% with total IgG and 92.5%, 87%, 95.0% with IgG4 isotype, respectively. Purified 27-29 kDa Ag presents the higher significant (P<0.01) results recording 90.0%, 83%, 93.3% with total IgG and 97.5%, 95%, 98.3% with IgG4 isotype, respectively. The results proved that combining the detection of IgG4 isotype using the 27-29 kDa Ag in sera of schistosomiasis haematobium patients in ELISA test could represent an effective immunodiagnostic tool for detecting infection in low worm burden population. This test could be useful in sero-epidemiolocal studies in low endemic areas and in diagnosis of infection in travelers to schistosomiasis endemic areas.