Cross reacting antibodies against keyhole limpet haemocyanin may interferewith the diagnostics of acute schistosomiasis

The number of individuals catching schistosomiasis has increased with the p opularity of 'primitive tourism' in Africa. Highly immunogenic material ori ginating from the intestine of intravascular adult schistosomes gives rise to an antibody response making possible early identification of infected in dividuals ruing serology. Antibodies against gut associated antigens (anti- GAA), detected by indirect immunofluorescence microscopy employing sections of adult worms as antigen may occur before the onset of egg production. In the present study we show that this well known schistosomiasis-specific an ti-GAA staining reaction can be confused with a similar staining reaction w ith ducts of both male and female worms. Antibodies with duct reactivity we re seen in sera both from schistosomiasis-patients and patients with some o ther invasive worm infections. Cross reactive anti-duct antibodies appear t o have different specificity. One cross reactive antibody reacted with anti genic epitopes present in keyhole limpet haemocyanin (KLH). Anti-duct react ivity could be inhibited by absorption with KLH. This was most obvious in t he triclinellosis patient sera.