IL4 and appendicitis: Also, in this study, preliminary results of repeated cytokine analyses using stocked samples from one patient (case AA42) showed high serum levels of interleukin-4 (IL-4), a marker of asymptomatic E. histolytica infection (20), at 3.5 months before the onset of acute appendicitis, and the level decreased immediately after treatment of amoebic appendicitis (data not shown).