Anti-Wolbachia antibodies and acute lymphadenopathy in lymphatic filariasis
Abstract number: O492
Salvana E.M., Gentil K., Hise A., Pearlman E., Hazlett F., Kazura J.
Background: Lymphatic filariasis (LF) afflicts 120 million people. While the most profound images of LF are elephantiasis and hydrocoele, acute disease in the form of lymphadenopathy, malaise and fever collectively termed adenolymphangitis (ADL) causes significant economic disenfranchisement and suffering in resource poor areas. The pathogenesis of acute LF is not well understood but the endosymbiont Wolbachia has been implicated, and has been shown to activate toll-like receptors. This study aims to examine adaptive immunity to Wolbachia and whether this affects development of acute disease.
Methods: Two studies were formulated using a pool of banked sera from a previous Mass Drug Administration (MDA) study in Papua New Guinea from 19931998. The first study looked at anti-WSP levels in individuals with a recent (within 30 days) ADL event using a case control design with age and sex-matched endemic controls. The second study was a retrospective cohort which looked at anti-WSP levels in longitudinal sera over a 6-year period with ADL as the primary outcome. ELISA using recombinant Wolbachia surface protein (WSP) was used to detect anti-Wolbachia antibodies. ELISA to detect anti-filaria antibody against crude Brugia antigen (BmA) was also performed.
Results: Antibody levels against WSP for the ADL group in Study 1 were significantly lower than the non-ADL group (p = 0.0006). Anti-BmA levels were not significantly different. In Study 2, anti-WSP levels in the pretreatment year were significantly lower (p = 0.0016) for those who developed ADL within the six year period. Odds ratio of developing ADL was 3.31 (p = 0.011) for an anti-WSP level lower than the median of the ADL group in the pretreatment year. Anti-WSP levels in succeeding sera in the subsequent treatment years were not significantly different between groups. Antibody levels for the entire cohort significantly increased from the pretreatment year to the post-treatment year (p = 0.0363). Anti-BmA levels were not significantly different between groups for all blood draw years.
Conclusion: Individuals exposed to LF with low anti-Wolbachia WSP antibody titers have a significantly higher risk of developing acute lymphadenopathy. This relationship holds whether the ADL event is recent or over six years. MDA results in a significantly higher anti-WSP antibody titer over time. These findings support an association between the pathogenesis of acute LF and adaptive immune response to Wolbachia endosymbionts.
|Session name:||Abstracts of 21st ECCMID / 27th ICC|
|Location:||Milan, Italy, 7 - 10 May 2011|
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