Urine- and serumβ2-microglobulin in patients with rheumatoid arthritis: A study of 101 patients without signs of kidney disease

Abstract

Serum levels and 24-hour urinary excretion of beta 2-Microglobulin (beta 2-M) was investigated in a group of 101 patients with rheumatoid arthritis (RA), without any other signs of renal disease in past or present, and in a comparable control group. Elevated 24-hour urinary beta 2-M excretion, due to renal proximal tubules dysfunction, was observed in 19% of the patients and not in the control group. There was a significant correlation with clinical signs of extra-articular RA. It is postulated that the observed increase may be an early symptom of renal involvement in RA. Elevated serum beta 2 levels, corrected for glomerular filtration rate, were observed in 44% of the RA patients and only in 3% of the control group and correlated with clinical signs of a more severe RA, as well as with increased 24-hour urinary beta 2-M excretion.

Renal involvement in rheumatoid arthritis

“…Beta-2-microglobulin is a marker of renal proximal tubular dysfunction. Viergever et al [41] found elevation of β2-microglobulin serum concentration in 44% and urine excretion in 19% of 101 RA patients. This correlated with a more severe RA and the presence of extra-articular disease manifestation.…”

Renal Enzymes and Microglobulins in Patients with Rheumathoid Arthritis

“…β 2-microglobulin (β2M) in urine is used for detection of tubular malfunction in glomerulonephritis [20] and is often used as sensitive marker for evaluation of renal function [21][22][23][24][25]. β2M is a polypeptide with small molecular weight (11.815 daltons).…”

Alanine Aminopeptidase, γ-Glutamyl Transferase and β2-microglobulin as Diagnostic Markers in Patients with Rheumatoid Arthritis

“…Examination of the brush border epithelium (BBE) of the proximal tubules confirms that alanine aminopeptidase, AAP (90%), alkaline phosphatase, AF (70%) and γ-glutamyl transferase, γ-GT (50%), constitute the biggest part of the total activity of these enzymes in the kidney (1). Because BBE is very sensitive to changes, these and other enzymes can be used as markers for secondary renal damage under the action of different diseases, medicines and toxines (2). Increased enzymatic activity can be a reflection of disease activity and of the residual functional capacity of the kidney.…”