[1] BRIGHAM & WOMENS HOSP, DEPT MED, DIV RENAL, BOSTON, MA 02115 USA
[2] HARVARD UNIV, SCH MED, BOSTON, MA 02115 USA
[3] UNIV AUTONOMA MADRID, CTR NACL BIOTECNOL, E-28049 MADRID, SPAIN
[4] BOSTON UNIV, SCH MED, DEPT MICROBIOL & IMMUNOL, BOSTON, MA 02109 USA
[5] BRIGHAM & WOMENS HOSP, DEPT PATHOL, DIV IMMUNOL RES, BOSTON, MA 02155 USA
[6] HARVARD UNIV, SCH MED, BOSTON, MA 02155 USA