EVALUATION OF HUMAN HYDATID-DISEASE BEFORE AND AFTER SURGERY AND CHEMOTHERAPY BY DEMONSTRATION OF HYDATID ANTIGENS AND ANTIBODIES IN SERUM

This study was performed to differentiate serologically between patien ts with hydatid disease which is active, and which has been successful ly cured. A total of 18 cases was included. Pre-treatment serum sample s were collected before surgery or chemotherapy. Post-treatment serum samples were collected at various intervals (3 days, 7 days, 1 month, 6 months, 1 year and 2 years) after surgery or chemotherapy. These ser a were tested for the presence of circulating hydatid antigen (CAg) by bacterial co-agglutination (Go-A) and counter-current immunoelectroph oresis (CIEP) tests, and for circulating hydatid antibodies (CAb) by i ndirect haemagglutination assay (IHA). Ten and eight sera, respectivel y, were positive out of 11 pre-operative and pre-chemotherapeutic sera tested for CAg by the Go-A and CIEP tests. Post-operative sera collec ted from these cases did not show any CAg by the CIEP test. However, C Ag was detected by Go-A in three and four serum samples collected on t he third and seventh day, respectively, after surgical removal of the cyst. However, the CAg levels in these post-operative sera showed a gr adual decline by the seventh day and were completely absent in the ser um specimens collected 1 month after surgery and 6 months after chemot herapy All the post-operative serum samples except two, collected 2 ye ars after surgical removal of the cyst, in seven cases of old hydatid disease, were negative for CAg by both the CIEP and Go-A tests. Unlike the CAg profile, no marked differences were noted between the CAb pro file of the pre-and post-treatment sera, as shown by the IHA test. Eve n 1 year after surgery or chemotherapy, two sera showed a marginal dec rease in their CAb titre. CAb at varying titres was still detectable i n all seven serum samples from old cases of hydatid disease, even 2 ye ars after surgical removal of the cyst. This study shows the value of serial pre-and post-operative or chemotherapy estimation of CAg by Go- A and CIEP as an index of cure or of continuing hydatid infection.