[1] NCI, Immunocompromised Host Sect, Pediat Oncol Branch, Bethesda, MD 20892 USA
[2] Univ Hosp Gasthuisberg, B-3000 Louvain, Belgium
[3] Univ Texas, MD Anderson Canc Ctr, Houston, TX 77030 USA
[4] Univ Athens, Laiko Gen Hosp, GR-10679 Athens, Greece
[5] AZ St Jan Brugge, Brugge, Belgium
[6] Univ Utah, Hlth Sci Ctr, Salt Lake City, UT 84112 USA
[7] Merck Res Labs, West Point, PA USA
[8] Univ Texas, Hlth Sci Ctr, San Antonio, TX 78285 USA
[9] Univ Manchester, Manchester M13 9PL, Lancs, England