1. National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland1;
2. Department of Veterans Affairs Medical Center2 and
3. Department of Immunology and Microbiology, Wayne State University Medical School, Detroit, Michigan3
4. Department of Microbiology and Immunology, MCP-Hahnemann School of Medicine,4 Philadelphia, Pennsylvania; and