Effects of Glucocorticoid Immunosuppression on Serum Cystatin C Concentrations in Renal Transplant Patients

Abstract

Cystatin C is a nonglycosylated basic protein (13.36 kDa) and can be found in a variety of biologic fluids ( 1). Cystatin C serum concentration is not influenced by gender, inflammation, or lean tissue mass and is regarded to be mainly determined by glomerular filtration rate (GFR) ( 2)( 3)( 4)( 5). Cystatin C has been described as meeting many of the characteristics of an ideal GFR marker (e.g., endogenously produced at a constant rate, freely filtered in the glomerulus, neither reabsorbed nor secreted in the renal tubule, not extrarenally eliminated) and has been reported to be at least as accurate as the commonly used serum creatinine to detect impaired renal function in various patient groups, including renal transplant patients ( 6)( 7)( 8)( 9)( 10)( 11)( 12)( 13)( 14)( 15)( 16)( 17)( 18)( 19)( 20)( 21)( 22)( 23)( 24).