No abstract

The enzyme-linked immunosorbent assay (ELISA) was successfully applied to detect IgE antibodies against parasitic antigens by using an additional antibody layer to attain an amplification effect. The sera of 18 Gurkha patients with clinical manifestations of acute trichinosis and 35 Chinese with other parasitic infections were tested for antibodies to Trichinella spiralis by IgE-, IgM- and IgG-ELISA, IgG-radioimmunoassay (RIA) and indirect haemagglutination test (IHA). ELISAs for detection of IgE and IgM antibodies provided a 100% specific and sensitive diagnosis. Although IHA, IgG-RIA and IgG-ELISA detected antibodies in 94% of patients, non-specific reactions were also observed in the two last named methods. Muscle biopsies were positive in only 56% of patients.

The role of lysosomes in the pathogenesis of MS was studied by biochemical and ultrastructural techniques. Biochemical studies were performed on samples from 21 MS autopsies. The analyses included assays of acid proteinase, acid phosphatase, peptidase, neutral proteinase and esterase. The material for electron microscopy was obtained from ten biopsies made on MS patients during stereotaxic thalamotomy. In preliminary studies, the effect of autolysis on enzymatic activities was measured. These studies showed that acid hydrolases were stable enough to warrant further investigation. All enzyme activities studied were increased at the border zones of plaques, whereas in the macroscopically normal white matter only acid hydrolase activities were increased. Correspondingly, in electron microscopic studies, increased lysosomal response was found especially in astrocytes but also in oligodendrocytes. In astrocytes the number of heterolysosomes was conspicously increased and they were seen both in the perikaryon and in the cell processes. Such lysosomes often contained myelin-like membrane material. The presence of foreign phagocytizing cells could not be demonstrated except around the blood vessels. Furthermore, it appeared that myelin layers were not phagocytized by direct peeling process. These studies, suggest that early lysosomal changes occur in MS white matter and that such changes are mainly due to the phagocytosis of myelin inside astrocyte lysosomes. The possibility that the astrocyte response is a secondary phenomenon, which is preceded by other myelin destroying mechanisms is discussed.