Quantitative and qualitative evaluation of plasma and urine α 1-microglobulin in healthy donors and patients with different haemolytic disorders and haemochromatosis

• Published in: Clinica chimica acta Vol. 386; no. 1; pp. 31 - 37
• Main Authors: Nordberg, Jonas, Allhorn, Maria, Winqvist, Ingemar, Åkerström, Bo, Olsson, Martin L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2007
• Subjects: Alpha-1-microglobulin; Haemolysis; Kidney; Lipocalins; Protein HC; GPI; IgA; α 1m; β 2m; Haemolysis; PNH; RIA; Alpha-1-microglobulin; Protein HC; Kidney; RBC; Lipocalins; DAT; ROS; t-α 1m; AIHA
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2007.07.017

The haem-binding protein α 1-microglobulin (α 1m) is involved in protection against oxidative damage induced by extracellular haem/haemoglobin. A carboxy-terminally truncated form of α 1m (t-α 1m), 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-α 1m is present in urine from a large cohort and if urinary and plasma α 1m/t-α 1m 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 α 1m and t-α 1m 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-α 1m in urine but the t-α 1m/α 1m 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 α 1m, albumin and β 2-microglobulin/creatinine ratios in urine indicating glomerulo-tubular dysfunction. The demonstration of t-α 1m 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.