PTH and Autoimmunity: Unremarkable CBC; ESR 21 mm/hour; CRP 0.5 mg/dL; glucose 91 mg/dL; normal renal, liver, and thyroid function; PTH 22.5 pg/mL; negative RPR, HIV, HBV, HCV; no folate or B12 deficiency; ACE 71 U/L; PSA 0.59 ng/mL; normal protein electrophoresis; IgA slightly elevated 6.35 g/L; negative autoimmunity (ANA, anti-dsDNA, ANCA, RF, CCP, SSA/SSB). 24-hour urine: lead and Bence-Jones proteins negative.