Arthritis & Rheumatism Official Journal of the American College of Rheumatology Editor Peter H. Schur, MD Room 422, Richardson Fuller Building 221 Longwood Avenue Boston, M A 02115 Associate Editors K . Frank Austen, MD, Boston Laurie H . Glirncher, 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 Donato Alarcon-Segovia, MD, Mexico City Gene V. Ball, MD, Birmingham Merrill D. Benson, MD, Indianapolis Anders 0. Bjelle, MD, GBteborg Stefano Bornbardieri, MD, Pisa Constance E. Brinckerhoff, PhD, Hanover Anne C. Brower, MD, Bethesda Gerd R. Burmester, MD, Erlangen Joel N . Buxbaum, MD, New York Grant W. Cannon, MD, Salt Lake City Pojen P. Chen, PhD, La Jolla Sheldon Cooper, MD, Burlington Chella S. David, PhD, Rochester Jean-Michel Dayer, MD, Genevcz Wallace V. Epstein, MD, Sun Francisco John Esdaile, MD, Montreal David T . Felson, MD, MPH, Boston David A. Fox, MD, Ann Arbor Daniel E. Furst, MD, Summit Committee for the Publication of A&R Dennis A. Carson, MD, Chair, La Jolla Constance E . Brinckerhoff, PhD, Hunover Bruce N . Cronstein, MD, New York David A . Fox, MD, Ann Arbor Gene G . Hunder, MD, Rochester H . Ralph Schumacher, MD, Philadelphia Editorial Staff Jane S. Diamond, MPH, Managing Editor, Atlanta Patricia K . Higgins, Assistant Manuging Editor, Atlanta Catherine 1. Morlino, Editorial Assistant, Boston Karla M. Schroeder, Production Editor, Philadelphiu Mary B. Goldring, PhD, Boston Ellen M. Gravallese, MD, Boston Peter K . Gregersen, MD, Manhasset John B. Harley, MD, PhD, Oklahoma City Vincent C . Hascall, Jr., PhD, Bethesda Louis W. Heck, Jr., MD, Birmingham Gene G. Hunder, MD, Rochester Robert W. Karr, MD, Iowa City James H. Kimura, PhD, Chicago Tadamitsu Kishimoto, MD, PhD, Osaka Joel M. Kremer, MD, Albany Michael Lockshin, MD, Bethesda Ravinder N. Maini, MD, London Charles J. Menkes, MD, Paris John Mort, PhD, Montreal John D. Mountz, MD, PhD, Birmingham Barbara W. Needleman, MD, Baltimore Barbara S. Nepom, MD, Seattle Harold E. Paulus, MD, Los Angeles Ross E. Petty, MD, PhD, Vancouver Marilyn C. Pike, MD, PhD, Boston Jordan S. Pober, MD, PhD, Boston Richard M. Pope, MD, Chicago John D. Reveille, MD, Houstori Lawrence C . Rosenberg, MD, Bronx Naomi F. Rothfield, MD, Furrnington James R. Seibold, MD, New Britnswick John S. Sergent, MD, Nashville Bernhard H . Singsen, MD, MPH, Wilmington Joel D. Taurog, MD, Dallas Ronald P. Taylor, PhD, Charlottesville A. N. Theofilopoulos, MD, La Jolla Ronald L. Wilder, MD, PhD, Bethesdu Robert F. Willkens, MD, Seattle John B. Winfield, MD, Chapel Hill J . Frederick Woessner, PhD, Miami Morris Ziff, PhD, MD, Dallas AMERICAN COLLEGE OF RHEUMATOLOGY Stephen E . Malawista, MD, New Haven, President John S. Sergent, MD, Nashville, First Vice-president and President-Elect Herbert Kaplan, MD, Denver, Second Vice-president Shaun Ruddy, MD, Richmond, Treasurer Arthur L . Weaver, MD, Lincoln, Secretary Mark Andrejeski, Atlanta, Executive Vice-president Published for the College by J. B. Lippincott Company Arthritis & Rheirmutisrn (ISSN 0004-3591) is published monthly for the American College of Rheumatology by J . B. Lippincott Company, at 12107 Insurance Way, Hagerstown, MD 21740. Business offices are located at 227 East Washington Square, Philadelphia, PA 19106. Printed in the U.S.A. Copyright lil 1992 by the American College of Rheumatology, Atlanta, Georgia. All rights reserved. Printed on acid-free paper effective with volume 32, number 1 I . Second class postage paid at Hagerstown, Maryland, and additional offices. Subscription information, orders or nonmember changes of address: (except Japan, India, Nepal, Bangladesh and Sri Lanka) 100 Insurance Way, Suite 114, Hagerstown, MD 21740, or call 1-800-638-3030;in Maryland, call collect 301-714-2300. In Japan, contact USACO Corporation, 13-12, Shimbashi I-chome, Minato-ku, Tokyo, 105 Japan. In India, Nepal, Bangladesh and Sri Lanka, contact Universal Subscription Agency Pvt. Ltd., 101-102 Community Centre (F.F.) Saket, New Delhi 110017, India. Members’ changes of address, American College of Rheumatology, 60 Executive Park South, Suite 150, Atlanta, GA 30329. Annual subscription rates: U.S. $95.00 individual, $135.00 institution, residentistudent rate (U.S. only), $55.00; all other countries except Japan, $135.00 individual, $175.00 institution; resident rate (Canada only), $95.00. Single copies $15.00, except for special issues. Rates for airmail delivery available upon request. Subscription rates in Japan: 30,600 yen individual, 39,000 yen institution (includes airmail postage). Copies will be replaced without charge if the publisher receives a request within 60 days of the mailing date in the U.S. or within 5 months in all other countries. The views expressed in articles, letters, and other communications published in Arthritis & Rheumarism are those of the authors and do not necessarily reflect the opinions of the editors, publisher, or American College of Rheumatology. The publisher does not investigate the information contained in the classified advertisements in this journal and assumes no responsibility concerning them. Further, the publisher does not guarantee, warrant, or endorse any product or service advertised in this journal. POSTMASTER: Send address changes to ARTHRITIS & RHEUMATISM, P.O. Box 1550, Hagerstown, MD 21740.