Determination of antibodies against Echinococcus granulosus using IHA, IFA and differentiation of these antibodies by Western Blot

Cystic echinococcosis is a helmintho-zoonosis caused by metacestode form of Echinococcus granulosus. The diagnosis of cystic echinococcosis is difficult by clinical features; it is supported by imaging techniques combined with serological methods that aim the determination of specific antibody response. In this study, 163 patients who referred with the suspicion of cystic echinococcosis to the Central Laboratory at Gaziantep University Şahinbey Research Hospital between May 2007 and July 2008 were evaluated serologically.Type Ig G antibodies against E. granulosus in serum samples of patients were investigated by a commercial indirect hemagglutination (IHA) test, by an indirect fluorescence antibody (IFA) test, and by an enzyme-linked immunosorbent assay (ELISA). Results were comfirmed by Western blot method. Out of 163 patients, 83 (51%) were positive with IHA, 85 (53%) were positive with IFA, and 70 (43%) were positive with ELISA. According to Western blot test, sensitivity and specifity of IHA test were 88.76% and 94.59%, respectively, for IFA sensitivity was 89.89% and specificity was 93.24%, and for ELISA sensitivity was 78.65% and specificity was 100%. Using Western blot technique, presence of antibodies against antigenic bands were determined, and their relationship to cyctic localization and biochemical parameters were investigated.As 94 out of 163 serum samples, which were positive with serological methods (IHA, IFA, ELISA) were studied with Western blot method; 66 of the cases were positive due to the presence of p7 kDa band, 23 were suspicious/intermediate due to the absence of p7 kDa band, but the presence of p16/18, p24/26 and p39 kDa bands, and 5 were negative due to the presence of p39 kDa band only. Four of these five negative cases were positive by IHA, and all of them was positive by IFA technique. Sixtynine cases which were negative with serological methods (IHA, IFA, ELISA), were negative with Western blot also. In 71 positive cases cystic echinococcosis was confirmed with surgery. However, although in 17 hepatic and six pulmonary cases, which were surgically proven, p7 and p16-18 kDa bands were not determined, other bands were found. These cases were evaluated suspiciously positive. No relationship between the bands and cyctic localization and biochemical parameters was found.As result, IFA and IHA methods were found equally sensitive and specific in the serological diagnosis of cystic hydatidosis, but ELISA method was found more spesific (100%) when compared to these two methods. In addition to that, due to its application facility and low cost, IHA method was found suitable to use.