Immunological resistance to human biosynthetic insulin--effects of immunosuppression and plasmapheresis.

A 55-year-old gentleman, after being treated for a short time with a diet and with Chlorpropamide, was switched to purified porcine insulin due to ketonuria and ketoacidosis. After a year the patient developed immunological insulin resistance (mean daily insulin dose: 3.72 U/kg body weight; anti-insulin antibodies 78%). In order to lower anti-insulin antibodies human recombinant DNA insulin was introduced into further therapy. Contrary to expectations, the patient did not reduce whatsoever his anti-insulin antibodies and his daily insulin dose increased up to 5.63 U/kg body weight. Introduction of combined immunosuppressive therapy (prednisone plus azathioprine) together with plasmapheresis resulted in rapid lowering of daily insulin requirement and reduction in anti-insulin antibodies. Immunosuppressive therapy was continued with 10 mg of prednisone and a year later the patients insulin daily requirement was 0.66 U/kg BW while his antibodies were 18%. The possible causes of insulin resistance to human recombinant DNA insulin are discussed as well as the advantage of combined immunosuppressive therapy together with plasmapheresis that was used for rapid lowering of insulin daily requirement and anti-insulin antibodies titer.

Peripheral blood mononuclear cell subsets during Trichinella spiralis infection in pigs.

The immune response of 'Yugoslav meat breed' pigs inoculated with low doses of Trichinella spiralis muscle larvae was followed over two to nine weeks of primary infection, by analysing changes in peripheral blood mononuclear cell subsets, the development of a humoral antibody response and muscle larvae burden. During the course of the infection, infected animals showed a persistent elevation of both CD4+ and CD8+ T cell subsets from days 15 to 60 after the parasite exposure. During this time, the number of peripheral blood mononuclear cells expressing major histocompatibility complex class II antigens was also increased, while no significant differences were found in the number of circulating monocytes/macrophages and B cells over time. Humoral antibody responses to muscle larvae excretory-secretory products were evident as early as 41 days after infection, while the muscle larvae were recovered as early as 27 days after infection. The increased levels of CD4+ and CD8+ T cell subsets, as well as cells expressing major histocompatibility complex class II antigens in pigs exposed to T spiralis, may be indicative of some considerable alterations in cell subsets that are involved in the regulation of the swine immune response to this parasite.

Comparative efficacy of antigen and antibody detection tests for human trichinellosis.

Sera collected from patients with suspected or confirmed exposure to Trichinella spiralis were tested for circulating parasite antigens and antiparasite antibodies. Using an immunoradiometric assay, excretory--secretory antigens from muscle-stage larvae of T. spiralis were detected in the sera of 47% of 62 patients with clinical trichinellosis and 13% of 39 patients without clinical signs but suspected of exposure to infected meat. In comparison, antibodies were detected using an indirect immunofluorescent test in the circulation of 100% of the 62 patients with clinical trichinellosis and 46% of the 39 patients with suspected exposure. The presence of antibodies specific to excretory-secretory products of T. spiralis muscle larvae was confirmed in the majority of the samples tested by a monoclonal antibody-based competitive inhibition assay. These results indicate that antibody detection is a more sensitive diagnostic method for human trichinellosis, but that antigen detection might be a useful confirmatory test because it is a direct demonstration of parasite products in the circulation.