Native and recombinant antigens in the immunodiagnosis of human cystic echinococcosis

To evaluate the diagnostic sensitivity and specificity of immunoelectrophor esis (IEP), indirect haemagglutination (IHA), enzyme-linked immunosorbent a ssay (ELISA) and immunoblotting (IB), we compared their ability in detectin g IgG antibodies to a hydatid fluid fraction (HFF) and to native and recomb inant antigen B of Echinococcus granulosus. We tested sere from patients wh o had cystic echinococcosis (CE) grouped according to their type of cysts ( n = 204), from patients wit other parasitic diseases (n = 21), lung or live r carcinomas (n = 6) or serous cysts (n = 26) and from healthy controls (n = 90). HFF-IB gave the highest sensitivity (80%) followed by ELISA (72%), I HA (54%) and IEP (31%), respectively. The diagnostic sensitivity significan tly (P<0.01) decreased as cysts matured from type I-II to type VII. Recombi nant and native antigen B-IB yielded similar sensitivity (74%). A large num ber of clinically or surgically confirmed CE patients (20%) resulted negati ve. In these patients' sera, IB to assess the usefulness of the recombinant E. granulosus elongation factor-1<beta>/delta in detecting IgE antibodies yielded 33% of positivity. Our findings underline the need to standardize t echniques and antigenic preparations and to improve the performance of immu nodiagnosis by characterizing new antigens and detecting distinct immunoglo bulin classes.