Filarial antibody responses in Wuchereria bancrofti transmission area are related to parasitological but not clinical status

In Wuchereria bancrofti transmission areas, three groups of individuals hav e been identified, according to the presence or absence of microfilariae or adult worm derived molecules in the blood compartment. These groups likely reflect individuals with different permissivity/resistance to the complete development of W. bancrofti cycle. The profile of filarial-specific immuno globulins was analysed in W. bancrofti-exposed individuals in French Polyne sia, according to the presence or absence of microfilariae (Mf) and adult w orms, measured by Og4C3 circulating antigen. Individuals harbouring adult w orms, have higher filarial-specific IgG4 bur lower IgG3 and IgE levels, tha n adult worm-free individuals, independently of the presence of Mf. Low fil arial-specific IgG1 and IgG2 levels were associated with the presence of Mf but independent of the presence/ absence of adult worms. The filarial anti body responses were associated with the parasitological status of individua ls but not with clinical symptoms such as hydroceles or limb lymphangitis o r elephantiasis. The reduction of filarial specific immunoglobulin levels w as higher after treatment with diethylcarbamazine than ivermectin, which li kely reflects the better effect of the former on W. bancrofti adult worms. However, reduction of antibody levels was also observed in Mf-and adult wor m-negative individuals. This could be due to the overall reduction of W. ba ncrofti transmission in the island where this study took place.