A recombinant antigen-based IgG4 ELISA for the specific and sensitive detection of Brugia malayi infection

An IgG4 ELISA based on a novel recombinant antigen was evaluated for detect ion of Brugia malayi infection, using 2487 sera from various institutions: 2031 samples from Universiti Sains Malaysia, 276 blinded sera from 2 other institutions in Malaysia, 140 blinded sera from India and 40 blinded sera f rom Thailand. These sera were from various groups of individuals, i.e., mic rofilaraemics, chronic patients, endemic normals, non-endemic normals and i ndividuals with other parasitic and bacterial infections. Based on a cut-of f optical density reading of 0.300, the IgG4 ELISA demonstrated specificity rates of 95.6=100%, sensitivity rates of 96-100%, positive predictive valu es of 75-100% and negative predictive values of 98.9-100%. These evaluation studies demonstrated the high specificity and sensitivity of this test for the detection of active B. malayi infection. Thus, the IgG4 ELISA would be very useful as a tool in diagnosis and in elimination programmes for brugi an filariasis.