[Hydatidosis: new concepts in an old disease (First part) (author's transl)]. / Hidatidosis: nuevos conceptos sobre una antigua enfermedad (1.a parte).

In the first part of this review several aspects of the classical echinococcosis due to E. granulosus are commented on (geographical distribution, morphological, epidemiological, taxonomic and pathogenetic characteristics). The real incidence of this disease in Spain is unknown due to the absence of global epidemiological data, especially by the lack of sero-epidemiological surveys. Epidemiological measures necessary to establish a control program for this zoonosis are recommended. In relation to the pathogenesis of the parasitosis, the authors mention some clinicopathologic characteristics which are conditioned to the anatomy and function of the organs where hydatids are located.

Specific double diffusion microtechnique for the diagnosis of aspergillosis and paracoccidioidomycosis using monospecific antisera.

Using experimental reference sera against species-specific antigens of Aspergillus fumigatus and Paracoccidioides brasiliensis in a microdouble diffusion technique, a simple and specific test for the immunodiagnosis of aspergillosis and paracoccidioidomycosis has been developed. Only sera that produced lines of identity with either one of the bands formed by the anti-C2 or the anti-E2 reference sera were considered positive for aspergillosis or paracoccidioidomycosis, respectively. The sensitivity of the diagnostic test was similar to those of the classical double diffusion and the immunoelectrophoresis test. No false positives were found in sera obtained from patients affected by other mycoses, nor from healthy controls. The amount of reagents for the specific test was ten fold less than that required by the classical double diffusion test.

Further observations on the specificity of antigen 5 of Echinococcus granulosus.

The presence of IgE antibodies to antigen 5 of Echinococcus granulosus was detected by means of radioimmunoelectrophoresis in the sera of two of six patients infected with E. multilocularis. Sera from three of these patients gave a precipitin band in gel diffusion tests identical to that produced by a monospecific rabbit anti-E. granulosus antigen 5 serum, when tested against whole hydatid fluid. Sera from 19 individuals infected with Fasciola hepatica, 20 with Schistosoma mansoni, and 5 with with Taenia saginata showed no detectable antibodies against antigen 5 of E. granulosus, The monospecific rabbit anti-E. granulosus antigen 5 serum did not react in immunodiffusion with homologous antigen when absorbed with either 4 mg/ml of whole hydatid fluid or with 200 mg/ml of a soluble E. multilocularis extract. Absorption of the monospecific antiserum with crude antigens of either F. hepatica, Onchocerca volvulus, S. mansoni, or T. saginata did not abolish the reaction with antigen 5. It appears, therefore, that antigen 5 can no longer be considered specific for E. granulosus, but is also present in E. multilocularis. In the light of this observation, some reevaluation of immunodiagnostic tests in hydatid disease will be necessary.

Identification and purification of the specific antigen of Paracoccidioides brasiliensis responsible for immunoelectrophoretic band E.

A new purified antigen (E2) of Paracoccidioides brasiliensis mycelial growth phase was isolated by immunoadsorption from a crude metabolic soluble extract of the fungus. The antiserum prepared in a rabbit by inoculation of E2 antigen developed only one immunodiffusion line with the crude metabolic extract. Findings on immunological analysis showed that E2 antigen is the antigenic component of immunoelectrophoretic band E. The isolated antigens did not possess detectable alkaline phosphatase activity. It reacted in immunodiffusion tests with all the sera (14/14) from P. brasiliensis infected patients containing precipitating antibodies.

Isolation of a specific antigen with alkaline phosphatase activity from soluble extracts of Paracoccidioides brasiliensis.

A specific antigen of Paracoccidioides brasiliensis was isolated from a metabolic extract of the fungus. The extraction was made by specific adsorption to and subsequent elution from a column containing a cross linked polymer to which the antibodies of a monospecific rabbit serum had been covalently attached. The purity of the final product was demonstrated by immunodiffusion analysis of the eluate using immune serum produced in a sensitized rabbit. The purified antigen was shown to have cationic electrophoretic mobility and alkaline phosphatase activity.

Comparative sensitivity and specificity of the Casoni intradermal and the immunoelectrophoresis tests for the diagnosis of hydatid disease.

The Casoni intradermal (ID) test, using two antigens, was compared with the immunoelectrophoresis (IEP) test for diagnosis in 47 surgically confirmed cases of hydatid disease and 73 non-hydatid persons. An antigen prepared from boiled hydatid cyst fluid (HF) was markedly more sensitive in the ID test than another prepared from whole HF but both produced false-positive reactions in three persons with other disease conditions. The IEP test yielded no false positives and its sensitivity was similar to the ID test using the more sensitive boiled HF antigen. Some patients were ID-positive and IEP-negative and vice-versa. Diagnostic sensitivity of both tests varied according to the localization and condition of the cyst. A detectable immune response was more frequent in patients with liver cysts than in those with lung cysts. Regardless of cyst localization, lowest diagnostic sensitivity was observed in patients whose cysts were intact and of the hyaline type, whereas recently broken cysts were associated with the most consistently detectable immune response. The limitations of the ID test are discussed and it is suggested that, until more specific antigens are available, there appears to be little value in utilizing this test where the more specific serological techniques are available.

[Reactivity of a purified antigen of Paracoccidioides brasiliensis with paracoccidioidomycosis and histoplasmosis sera]. / Evaluación de la reactividad de un antígeno purificado de Paracoccidioides brasiliensis frente a sueros de paracoccidioidomicosis e histoplasmosis

The immunoelectrophoretic reactivity of a "crude" and a "purified" antigens of Paracoccidiodes brasiliensis against the sera of confirmed cases of paracoccidioidomycosis and histoplasmosis was evaluated. The "crude" antigen revealed precipitating antibodies in both the homologous and the heterologous human sera; the number of precipitating systems being higher with the former. The "purified" antigen reacted only with the homologous sera. It is postulated that the use of such "purified" antigen may significantly reduce the non specificity of the serologic tests in the immunodiagnosis of paracoccidioidomycosis.

Evaluation of whole and purified hydatid fluid antigens in the diagnosis of human hydatidosis by the immunoelectrophoresis test.

Whole sheep hydatid cyst fluid (WHF) and purified hydatid fluid antigens (PHF) were evaluated in the immunoelectrophoresis (IEP) test for the diagnosis of human hydatid disease. A higher sensitivity was obtained using the PHF than with the WHF antigen but false positive results were observed with the former in 22.4% of the 102 non-hydatid sera examined. Using the presence of arc 5 as the criterion of positivity however, no false positives were observed in non-hydatid sera with the WHF antigen. It is postulated that the number of bands other than arc 5 may be of value in the diagnosis of hydatid disease by the IEP test, in cases where this diagnostic arc is absent.

Evaluation of four variants of the indirect hemagglutination test for human hydatidosis.

The comparative sensitivity and specificity of four technical variants of the indirect hemagglutination test (IHA) for hydatidosis with tannic acid, glutaraldehyde, benzidine and formol treated cells, the same pool of hydatid cyst fluid and sera from hydatid and non-hydatid persons was studied. The number of reactors in each group of sera and the degree of reactivity of each serum sample varied with the type of IHA test. The sensitivity and specificity of each technique was related to the criterion on which IHA test positivity was based and to the group of sera examined. Of the four techniques, that employing tannic acid was considered as the choice IHA test for hydatid immunodiagnosis. The findings are discussed in terms of their implications to the use of a standard serum of known IHA test titer for reference purposes and to the significance of IHA test results for diagnostic and seroepidemiological studies.

Evaluation of three immunodiagnostic tests for human hydatid disease.

The comparative sensitivity and specificity of the immunoelectrophoresis (IEP), latex agglutination (LA) and indirect hemagglutination (IHA) test for hydatidosis were evaluated using a single hydatid cyst fluid pool as antigen and the same hydatid and nonhydatid sera and were found to vary with the type of IHA test, the criterion for IHA test positively and the group of sera selected for study. The sensitivity of the LA and IEP tests was comparable, both tests correlated well and neither gave a positive result in the nonhydatid sera studied. The sensitivity of the IEP test was higher when IHA test positivity was based on diagnostically significant titers but not when all IHA test reactors were considered as positive to this test. The merits and limitations of the LA and IHA tests in diagnostic and seroepidemiologic studies of human hydatidosis are discussed. On the basis of the present findings, the use of the LA test and possibly of the tannic acid IHA test, to screen for IEP test positive sera is proposed as the most reliable immunodiagnostic approach to estimate the prevalence of human hydatidosis for seroepidemiologic purposes and also for detecting hydatidosis cases in the field.