Toxoplasmosis and systemic lupus erythematosus. Comparative serological studies.

There are still controversial views as to the relation between SLE and toxoplasmosis. Therefore, we looked for serological markers in both diseases. In patients with SLE (17), toxoplasmosis (28), and in normal controls (28) anti-Toxoplasma gondii antibodies, anti-nuclear antibodies of different specificities, anti-histone and anti-cardiolipine antibodies, as well as antibodies against most common public idiotypes were measured. Significant increases in antinuclear antibodies and other SLE-related antigens were observed in patients with SLE. On the contrary, low levels of these antibodies were found in toxoplasmosis patients and in controls. The same was true for 16/6 anti-DNA idiotype antibodies. The incidence of anti-Toxoplasma antibodies in SLE sera did not differ in comparison with that in the normal population. Our data suggest that subacute and chronic toxoplasmosis do not play essential roles in generating the antibodies that are important to the pathogenetic mechanism operating in SLE.

An enzyme-linked immunosorbent assay for diagnostic detection of Taenia saginata copro-antigens in humans.

An immunodiagnostic sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the detection of soluble Taenia saginata antigens in stool samples (copro-antigens) of infected humans, using affinity-purified polyclonal antibodies obtained from rabbits hyperimmunized with excretory/secretory antigens derived from T. saginata maintained in vitro. Investigation of operating characteristics showed very low cross-reactivity with crude antigens from helminths other than Taenia, including Dipylidium caninum and Diphyllobothrium latum. The specificity of the assay was 95% when testing stool samples from 100 persons who were either infected with Ascaris lumbricoides, Trichuris trichiura, hookworms, Enterobius vermicularis or Hymenolepis nana, or who had no intestinal helminthosis detected. Analysis of diagnostic sensitivity demonstrated that in 85% of 34 samples from 23 untreated persons with intestinal T. saginata infection (selected by previous proglottid and/or egg detection) copro-antigens were detected by the T. saginata ELISA. In the same samples, Taenia eggs were detected in 62%. Only 41% of the samples reacted positively in a heterologous T. hydatigena ELISA. Post-treatment control revealed a high concentration of T. saginata copro-antigens for 1-4 d after administration of niclosamide or praziquantel, and negative values 9-17 d after treatment. The Taenia copro-antigens remained detectable by ELISA even after storage of untreated faeces at 25 degrees C for at least 5 d.