Antibodies to echinococcus in serum
AT to echinococcus in serum is normal.
To diagnose echinococcosis, serological diagnostic methods have been developed: RPGA, RSK, latex agglutination reaction with Ar from the fluid of echinococcal bubbles and ELISA.
The most effective for the diagnosis of echinococcus is the ELISA method. However, the use of this method is limited by the fact that many carriers of echinococcal cysts do not develop an immune response, no blood in the blood is formed. ELISA gives positive results in 90% of patients with cysts in the liver and only in 50-60% of patients with lung disease. High AT titers( above 1: 400) have a sensitivity of 90% and a specificity of less than 100% in cases with daughter cysts in the liver and peritoneum;60% of the sensitivity - when the lungs and bones are affected;10% - false-positive results( cysticercosis, collagenoses, malignant neoplasms).After surgical removal of cysts, the determination of AT to serum echinococcus is used to monitor the radicality of the operation performed. Disappearance of AT 2-3 months after the operation indicates a radical cyst removal, a decrease in the titer of AT and its subsequent growth in the postoperative period - the recurrence of the cyst. In some cases, after successful surgical treatment, elevated titers can last for years. The maximum detectability of echinococcosis by ELISA method( up to 98%) was noted when echinococcal blisters of live parasite were located in the liver, abdominal cavity and retroperitoneal space, as well as in multiple and combined lesions. With lung lesions, as well as in the presence of one to three cysts of a small( up to 2 cm) size, the effectiveness of serological diagnosis is lower and ranges between 70-80%.The least informative method is ELISA for echinococcosis of the nervous( dorsal or brain, eye), muscle or bone tissue, as well as for the dead and calcified parasite( sensitivity does not exceed 40%).High AT titers may be in patients with an active process, more often localized in the organs of the abdominal cavity. In the case of pulmonary localization of echinococcus cysts( even in the presence of large cysts), the AT titers may be low.
Low AT titers to echinococcus can be detected in the early period of the disease( cysts up to 2 cm in diameter), as well as larvocysts in calcified shells;a sharp decrease in titers is possible with a far-reaching process, in the late, inoperable stage of echinococcosis.
When using serological methods for diagnosing echinococcosis, false positive results are possible when there are non-specific ATs in the blood that are similar in structure to AT to echinococcus. The most often false positive results are revealed in somatic and infectious diseases, accompanied by extensive destructive processes in the affected organs( cirrhosis of the liver, pulmonary tuberculosis and other tissues, oncological diseases).False positive reactions are possible with other helminthiases( for example, opisthorchiasis, fasciosis and cysticercosis).
Serological studies are used for the primary diagnosis of echinococcosis, evaluation of the results of operative and conservative treatment and monitoring of patients in dynamics, as well as for the early detection of recurrences of the disease. Localization and viability of larvocyst of echinococcus hydatidid and alveolar, the intensity of invasion, as well as the state of the host's immune system, affect the intensity of AT formation and the detection of invasives with the help of serological reactions.
Indications for the appointment of serological tests:
■ the presence of volumetric education or cysts in the liver and other organs;
■ Epidemiologically significant contingents - persons classified as at risk( hunters and their families, zootechnicians, shepherds and shepherds, workers in tanneries, etc.), as well as those living in foci of echinococcosis.