Diarrhoeal disease: current concepts and future challenges. Rapid detection of enteric infections by measurement of enteric pathogen-specific antibody secreting cells in peripheral blood.

Enteric infections and diarrhoeal disease are important causes of morbidity and mortality. Infections are often difficult to diagnose, especially when access to sophisticated laboratory facilities is limited. In an attempt to develop a rapid method of diagnosis, which might not require an advanced laboratory, advantage was taken of the observation that precursors of lymphocytes secreting immunoglobulin A (IgA), generated in response to mucosal stimulation with an antigen, are transiently present in peripheral blood. Detection of cells in peripheral blood bearing IgA specific for a pathogenic microbe should indicate current infection. This hypothesis was tested using peripheral blood mononuclear cells collected from volunteers who were clinically 'normal', had experimentally induced shigellosis, had naturally acquired shigellosis, or had naturally acquired typhoid fever. The method was sensitive for detection of Salmonella typhi infection and less sensitive for detection of Shigella infection. The antibody secreting cell procedure has good potential as a rapid, simple diagnostic procedure if applied during the acute phase of infection.