Although the focus of our study was a Pseudomonas IT, our study has wider applicability to other toxins and ITs that cause atypical HUS, such as Shiga toxin (11), Combotox®, a ricin-based IT targeting CD19 and CD22 (36), and DAB486IL-2, a diphtheria toxin-based IT targeting interleukin-2 (37, 38). The gene discussed is CD19; the disease is hemolytic-uremic syndrome.