[1] Marshfield Clin Fdn Med Res & Educ, Dept Pulm & Crit Care Med, Marshfield, WI 54449 USA
[2] Marshfield Clin Fdn Med Res & Educ, Dept Internal Med, Marshfield, WI USA
[3] Ronald Reagan UCLA Med Ctr, Dept Rheumatol, Santa Monica, CA USA
[4] Marshfield Clin Fdn Med Res & Educ, Dept Pathol, Marshfield, WI USA
[5] Christiana Care Hlth Syst, POB 1668, Wilmington, DE 19899 USA