[1] Corporal Michael J Crescenz Vet Affairs Med Ctr, Philadelphia, PA USA
[2] Univ Penn, Dept Dermatol, Philadelphia, PA 19104 USA
[3] Univ Penn, Dept Biostat & Epidemiol, Philadelphia, PA 19104 USA
[4] Oklahoma Med Res Fdn, Arthrit & Clin Immunol Program, 825 NE 13th St, Oklahoma City, OK 73104 USA