Contribution of specific anti-hydatid IgG subclasses in the diagnosis of echinococcosis primary infection and relapses.

BACKGROUND: Serological diagnosis of hydatid disease still faces problems of sensitivity, limiting its use to either diagnosis or post-surgical monitoring. The use of IgG subclasses seems to overcome these difficulties. The contribution of IgG subclasses was evaluated in the diagnosis of primary infested and hydatid cyst relapse patients. METHODS: A group of patients (n = 34) diagnosed for the first time with liver cystic echinococcosis (CE) and a group of patients with CE surgical recurrence were included. Enzyme-linked immunosorbent assay anti-hydatid antigens (HA) specific IgG1, 2, 3, and 4 subclasses were analyzed by ROC curves. RESULTS: ROC curve analyses demonstrated that IgG4 had the ability to discriminate between primary infested and relapsed groups whereas IgG2 was not discriminatory. The sensitivity of IgG4 was statistically higher in the relapsed cases group (97.1% versus 70.6%, p = 0.008). CONCLUSIONS: anti-HA specific IgG2 was the best marker of primary infestation whereas IgG4 was the best marker of relapse.