INVASIVE AMEBIASIS IS ASSOCIATED WITH THE DEVELOPMENT OF ANTINEUTROPHIL CYTOPLASMIC ANTIBODY

Features of tissue damage in invasive amoebiasis, in particular polymo rphonuclear neutrophil (PMN) degranulation and vasculitis, bear resemb lance to that seen in Wegener's granulomatosis, the latter being assoc iated with the presence of anti-neutrophil cytoplasmic antibodies (ANC A). We therefore tested sera from patients with confirmed amoebic live r abscess (ALA) for the presence of ANCA by means of an indirect fluor escent antibody test using pure neutrophils as substrate. ANCA was det ected in 97.4% of amoebic sera; the pattern of staining was cytoplasmi c, homogeneous, without central accentuation (C-ANCA). A proteinase 3 (PR3) ELISA demonstrated PR3 specificity in 75% of C-ANCA-positive ALA sera. Possible explanations are (i) a cross-reacting antibody to a co mponent of Entamoeba histolytica, or (ii) an antibody to PMN component s released, and possibly modified, by the action of E. histolytica on PMN. It is possible that this antibody contributes to the pathogenesis of invasive amoebiasis.