Arthritis & Rheumatism Official Journal of the American College of Rheumatology Editor Peter H. Schur, MD Room 422, Richardson Fuller Building 221 Longwood Avenue Boston, MA 02115 Associate Editors K. Frank Austen, MD, Boston Laurie H. Glimcher, MD, Boston Don L. Goldenberg, MD, Boston Martin G. Larson, SD, Boston Matthew H . Liang, MD, MPH, Boston Dwight R. Robinson, MD, Boston Clement B. Sledge, MD, Boston Michael E. Weinblatt, MD, Boston Barbara N. Weissman, MD, Boston Editorial Board John P. Atkinson, MD, St. Louis Gene V. Ball, MD, Birmingham Merrill D. Benson, MD, Indianapolis Constance E. Brinckerhoff, PhD, Hanover Anne C. Brower, MD, Bethesda Joel N. Buxbaum, MD, New York Pojen P. Chen, PhD, La Jolla Chella S . David, PhD, Rochester Jean-Michel Dayer, MD, Geneva Wallace V. Epstein, MD, Sun Francisco John Esdaile, MD, Montreal David T. Felson, MD, MPH, Boston David A. Fox, MD, Ann Arbor Steven M. Friedman, MD, New York Shu Man Fu, MD, PhD, Charlottesville Daniel E. Furst, MD, Summit Don L. Goldenberg, MD, Boston Peter K. Gregersen, MD, Manhasset John B. Harley, MD, PhD, Oklahoma City Committee for the Publication of A&R Dennis A. Carson, MD, Chair, La Jolla Frank C. Amett, MD, Houston Constance E. Brinckerhoff, PhD, Hanover Bevra H. Hahn, MD, Los Angeles Gene G. Hunder, MD, Rochester H. Ralph Schumacher, MD, Philadelphia Editorial Staff Jane S. Diamond, Managing Editor, Atlanta Patricia K. Higgins, Assistant Managing Editor, Atlanta Catherine I. Morlino, Editorial Assistant, Boston Vincent C. Hascall, Jr., PhD, Bethesda Louis W. Heck, Jr., MD, Birmingham Gene G. Hunder, MD, Rochester Robert W. Karr, MD, Iowa City Robert P. Kimberly, MD, New York James H. Kimura, PhD, Chicago Tadamitsu Kishimoto, MD, PhD, Osaka Brian L. Kotzin, MD, Denver Joel M. Kremer, MD, Albany Peter E. Lipsky, MD, Dallas Michael Lockshin, MD, Bethesda Ravinder N. Maini, MD, London John Mort, PhD, Montreal John D. Mountz, MD, PhD, Birmingham Carl F. Nathan, MD, New York Barbara W. Needleman, MD, Baltimore Richard S. Panush, MD, Livingston Harold E. Paulus, MD, Los Angeles Ross E. Petty, MD, PhD, Vancouver Marilyn C. Pike, MD, PhD, Boston Jordan S. Pober, MD, PhD, Boston John D. Reveille, MD, Houston Lawrence C. Rosenberg, MD, Bronx Naomi F. Rothfield, MD, Farmington Robert L. Rubin, PhD, La Jolla Ralph Schrohenloher, PhD, Birmingham James R. Seibold, MD, New Brunswick John S . Sergent, MD, Nashville Bernhard H. Singsen, MD, Wilmington Joel D. Taurog, MD, Dallas Ronald P. Taylor, PhD, Charlottesville A. N. Theofilopoulos, MD, La Jolla George C. Tsokos, MD, Bethesda Ronald L. Wilder, MD, PhD, Bethesda Robert F. Willkens, MD, Seattle John B. Winfield, MD, Chapel Hill J. Frederick Woessner, PhD, Miami AMERICAN COLLEGE OF RHEUMATOLOGY Robert F. Meenan, MD, MPH, Boston, President Stephen E. Malawista, MD, New Haven, First Vice-President and President-Elect John S. Sergent, MD, Nashville, Second Vice-President Herbert Kaplan, MD, Denver, Secretary Shaun Ruddy, MD, Richmond, Treasurer Executive Staff Mark Andrejeski Lynn Bonfiglio Sherrie Cathcart Donna Cosola Kathryn Hudson Ronald Olejko Jeffery Quesenbeny Published for the College by J. B. Lippincott Company Arthritis & Rheumaiism (ISSN 0004-3591) is published monthly for the American College of Rheumatology by J. B. Lippincott Company, at 100 Insurance Way, Suite 114, Hagerstown, MD 21740. Business offices are located at East Washington Square, Philadelphia, PA 19105. Printed in the U.S.A. Copyright 1991 by the American College of Rheumatology, Atlanta, Georgia. All rights reserved. Printed on acid-free paper effective with volume 32, number 11. Second class postage paid at Hagerstown, Maryland, and additional offices. 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