II. Unbound versus total serum gold concentration: pharmacological actions on cellular function

Area of Science:

• Biochemistry
• Immunology
• Pharmacology

Background:

• Unbound serum gold (UBSG) is largely unstudied due to rapid decay and low concentrations.
• Existing analytical methods are insufficient for UBSG quantitation in vivo.
• Chrysotherapy involves gold administration for treating various conditions.

Purpose of the Study:

• To develop a methodology for quantifying UBSG during chrysotherapy.
• To investigate the effects of UBSG on cellular functions.
• To compare UBSG levels between oral and systemic gold administration.

Main Methods:

• Development of a novel analytical methodology for UBSG quantitation.
• Administration of gold compounds (auranofin and systemic) to subjects.
• Assessment of lymphocyte mitogen response and polymorphonuclear phagocytosis.

Main Results:

• A new method enabled the study of UBSG during chrysotherapy.
• UBSG levels were found to be labile and decline rapidly after peaking.
• Peak UBSG concentrations correlated with suppressed lymphocyte and phagocytic functions.
• Oral auranofin (3 mg BID) yielded a higher percentage of UBSG compared to systemic therapy (50 mg/wk).

Conclusions:

• The developed methodology allows for UBSG quantitation and study.
• UBSG plays a role in modulating immune cell functions during gold therapy.
• Oral gold administration results in higher unbound serum gold levels than systemic administration.