Immunosurveillance of alveolar echinococcosis by specific humoral and cellular immune tests: long-term analysis of the Swiss chemotherapy trial (1976–2001)

Background/Aims Long-term chemotherapy with benzimidazoles is beneficial in non-resectable alveolar echinococcosis (AE). Criteria to track early therapeutic efficacy are lacking and the clinical impact of immunosurveillance is unsettled. We aimed to analyze this issue particularly for assessing the putative parasitocidal efficacy of chemotherapy. Methods The present study is part of our prospective Swiss trial outlined previously and comprises 57 patients with a median follow-up of 18.5 (3–30) years and with repeated tests of humoral and cell-mediated immunity. The series was subdivided into group A (n=23; curative surgery) and group B (n=34: non-resectable AE). Results Long-term survival was 87% (group A) and 76% (group B). The profiles of specific antibodies against EmII/3-10 antigen normalized within 3 years in most group A-patients, but remained above the cut-off value in 40% of group B-patients. This lack of normalization was associated with lower bioavailability of mebendazole. AE-recurrence after ‘radical’ surgery (up to 13 years) was associated with high anti-EmII/3-10 concentrations in 7 of 8 cases. Following abrogation of longterm chemotherapy in group B, no AE-recurrence occurred in 9/18 patients, suggestive of parasitocidal efficacy and documented by a normal EmII/3-10 profile. Conclusions The EmII/3-10 profile is of value in monitoring AE after surgery and/or chemotherapy.