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


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Nordberg
Jonas
J
Department of Clinical Sciences Lund University, Sweden.
Allhorn
Maria
M
Winqvist
Ingemar
I
Akerström
Bo
B
Olsson
Martin L
ML
D000510:Alpha-Globulins / Q000032:analysis / Q000652:urine*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015153:Blotting, Western; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood / Q000652:urine; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006402:Hematologic Diseases / Q000175:diagnosis*; D006432:Hemochromatosis / Q000175:diagnosis*; D006801:Humans; D007678:Kidney Glomerulus / Q000473:pathology; D008297:Male; D011863:Radioimmunoassay; D001613:beta 2-Microglobulin / Q000097:blood / Q000652:urine
D000510:Alpha-Globulins; D015415:Biomarkers; C016001:alpha-1-microglobulin; D001613:beta 2-Microglobulin; D003404:Creatinine