Comparative evaluation of an ELISA based on recombinant polypeptides and IFA for serology of malaria

In the present investigation we compare the performance of a solid-phase assay based on three recombinant polypeptides corresponding to three asexual blood-stage antigens of P. falciparum (ELISA MIXT) with the reference method for the measurement of antimalaria antibodies: indirect immunofluorescence antibody assay (IFA). Sera collected from persons with various degrees of exposure to malaria were selected: sera from inhabitants of a malaria endemic area (Group I), European patients with acute malaria infection (Group II) and blood donors with clinical symptoms of sickness or fever during a stay in malaria endemic areas. 86% of the sera gave concording results by ELISA MIXT and IFA. The correlation was 100% for sera of Group I but discrepancies were observed for Groups II and III. The great majority of the differences were due to sera positive on ELISA MIXT but not by IFA. Most of the sera positive on ELISA MIXT reacted with parasite-derived components only on Western-blot. These results underline the potential of the ELISA MIXT for epidemiologic studies.