In these patient samples, both anti-O4 IgM and IgG exhibited a significantly greater median fold increase after infection with S. Typhimurium (4.2-fold and 4.9-fold, respectively) than infection with non–group B NTS (1.0-fold and 0.9-fold, respectively) or Shigella organisms (1.2-fold and 1.04-fold, respectively; Supplementary Figure 1A and 1B). The gene discussed is CD40LG; the disease is infection.