CD40LG and Guillain-Barre syndrome: Odds of having IgM serum antibodies against GMI, GM2, GD1a, GD1b, and GT1b gangliosides in Guillain-Barré Syndrome cases and patient-controls for all cases and controls, for patients reporting diarrhea, and for patients excreting Campylobacter, the Arab Republic of Egypt, April 2001 through September 2003.