1. From the Department of Experimental Immunohaematology (P.d.C.M., N.v.d.B., P.L.H., J.J.Z.), Sanquin Research, Amsterdam, The Netherlands; Department of Pulmonary Diseases (L.H.U., L.K.), University Hospital Utrecht, Utrecht, The Netherlands; Department of Hematology (J.J.Z.), Academical Medical Center, Amsterdam, The Netherlands.