RESUMO
Methods for the detection of antigens, antibodies and immune complexes in the cerebrospinal fluid (CSF) of patients with neurological manifestations suggestive of cerebral gnathostomiasis were developed, in the hope that they may be useful in confirming the diagnosis of Gnathostoma spinigerum infection. Gnathostoma antigens were determined by a sandwich enzyme linked immunosorbent assay (ELISA) using antibodies from rabbits immunized with the excretory/secretory (ES) antigens obtained from the in vitro supernatant fluid in which the third-stage G. spinigerum larvae were maintained. With a biotin streptavidin procedure, the presence of G. spinigerum antigens as low as 2 ng in one ml of CSF could be detected. An indirect ELISA was used for the quantitation of IgG antibodies in the paired serum and CSF of these patients. A complement consumption method was used for the detection of immune complexes in the concentrated CSF specimens. Of the 11 patients with clinical signs and symptoms suggestive of having G. spinigerum infection involving the central nervous system, only one patient had antigens detected in the CSF and in this one patient no antibody could be demonstrated. One other patient had immune complexes in her CSF. All remaining patients had IgG antibodies demonstrable in the CSF specimens. These data suggest that the detection of IgG antibodies in CSF is more reliable than the other two methods in confirming the diagnosis of cerebral gnathostomiasis.