Immunology of cystic echinococcosis (hydatid disease).

BACKGROUND: The neglected disease cystic echinococcosis is caused by larval Echinococcus granulosus flatworms, which form bladder-like hydatid cysts in liver, lungs, and other organs. SOURCES OF DATA: Published literature. AREAS OF AGREEMENT: Establishing larvae are susceptible to antibody-dependent killing, as attested by successful animal vaccination, whereas once established they are partially protected by the so-called laminated layer. Host responses are Th2 dominated, with a Th1 component. Diagnostic antigens from cyst fluid are known, but responses appear absent in one-fifth of patients. AREAS OF CONTROVERSY: Is evasion mainly based on induction of Th2 or regulatory responses by the parasite? GROWING POINTS: The parasite induces regulatory responses. The laminated layer has immune-regulatory properties. AREAS TIMELY FOR DEVELOPING RESEARCH: Develop tools for functional genomics; characterize immunologically interesting proteins suggested by genomic information; analyse infection in broader context of granulomatous responses; identify molecules secreted/excreted by intact larvae/cysts towards their outside, including diffusible immune-regulators.