Quantitative and qualitative evaluation of plasma and urine alpha1-microglobulin in healthy donors and patients with different haemolytic disorders and haemochromatosis

• Published in: Clinica chimica acta Vol. 386; no. 1-2; p. 31
• Main Authors: Nordberg, Jonas, Allhorn, Maria, Winqvist, Ingemar, Akerström, Bo, Olsson, Martin L
• Format: Journal Article
• Language: English
• Published: Netherlands 01.11.2007
• Subjects: Alpha-Globulins - analysis; Alpha-Globulins - urine; beta 2-Microglobulin - blood; beta 2-Microglobulin - urine; Biomarkers - blood; Biomarkers - urine; Blotting, Western; Case-Control Studies; Creatinine - blood; Creatinine - urine; Electrophoresis, Polyacrylamide Gel; Female; Hematologic Diseases - diagnosis; Hemochromatosis - diagnosis; Humans; Kidney Glomerulus - pathology; Male; Radioimmunoassay
• ISSN: 0009-8981
• DOI: 10.1016/j.cca.2007.07.017

The haem-binding protein alpha(1)-microglobulin (alpha(1)m) is involved in protection against oxidative damage induced by extracellular haem/haemoglobin. A carboxy-terminally truncated form of alpha(1)m (t-alpha(1)m), formed by reactions with haemoglobin, degrades haem into a yellow-brown chromophore linked to the protein. The aim of this work was to investigate if t-alpha(1)m is present in urine from a large cohort and if urinary and plasma alpha(1)m/t-alpha(1)m concentrations are changed in patients with haemolytic disorders and haemochromatosis. Urine and blood from patients (n=20) and a control group (n=22) were investigated for alpha(1)m and t-alpha(1)m by gel electrophoresis, Western blotting and radioimmunoassay. Data were compared to clinical chemistry data and medical records. Two thirds of all studied subjects displayed t-alpha(1)m in urine but the t-alpha(1)m/alpha(1)m ratio was not increased in patients. Instead, significantly elevated ratios were found in females compared to males. Patients with intravascular or extravascular haemolysis showed higher alpha(1)m, albumin and beta(2)-microglobulin/creatinine ratios in urine indicating glomerulo-tubular dysfunction. The demonstration of t-alpha(1)m in urine of this cohort may be of importance in quantitative clinical chemistry. Whilst impaired kidney function due to intravascular haemolysis is well-known to occur, it is an unexpected finding in a group of patients with extravascular haemolysis.