1. From the Immunology and Rheumatology Division (V.M., J.J.D.B., H.D.), Department of Pediatrics, Sainte-Justine University Hospital Center; Allergy and Immunology Division (V.M.), Sacré-Coeur Hospital; Neurology Division (C.-T.E.N.), Department of Pediatrics; Intensive Care Division (T.F., A.B.), Department of Pediatrics; Clinical Department of Laboratory Medicine (A.B.), OPTILAB; and Nephrology Division (A.-L.L.), Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, Canada.