Rob C Aalberse1, Theo Rispens2. 1. Division of Research, Department of Immunopathology, Sanquin Blood Supply, Amsterdam, The Netherlands; Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: r.aalberse@sanquin.nl. 2. Division of Research, Department of Immunopathology, Sanquin Blood Supply, Amsterdam, The Netherlands; Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.