From the Department of Pediatrics, University of Florida, Gainesville (J.N.); Harvard Medical School, Boston (W.A.W.); and the Department of Pediatrics, Massachusetts General Hospital for Children, Charlestown (W.A.W.). Address reprint requests to Dr. Walker at the Mucosal Immunology Laboratory, Department of Pediatrics, Massachusetts General Hospital for Children, 114 16th St., Boston, MA 02129-4404, or at [email protected].
Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.
