Human alpha 1-microglobulin: its measurement and clinical significance.
alpha 1-Microglobulin (alpha 1-M), also called protein HC, is a low-molecular-weight (LMW) glycoprotein (about 30 kDa) with unique physicochemical properties. Using purified urinary alpha 1-M a standard and specific antibody against alpha 1-M, an assay system for alpha 1-M was developed, and the clinical significance of this protein was investigated by measuring total levels of alpha 1-M under physiological and pathological conditions. alpha 1-M is distributed in various body fluids: in serum, it consists mainly of free LMW alpha 1-M and monomeric IgA-alpha 1-M complex. The total alpha 1-M level in serum and urine usually reflects LMW alpha 1-M variation sensitively, and its determination is quite useful as an indicator of renal glomerulotubular dysfunction and hepatic dysfunction. Serum levels can vary, depending on IgA-alpha 1-M complex level, in parallel with the IgA concentration. The heterogeneity of alpha 1-M purified from different sources of urine by different procedures and underestimation of IgA-alpha 1-M complex by solid-phase antibody assays can be important causes for the discrepancy of serum levels between assays.
Department of Clinical Pathology, Jichi Medical School, Tochigi-Ken, Japan.
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Itoh
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Kawai
D000510:Alpha-Globulins / Q000032:analysis* / Q000276:immunology / Q000652:urine; D000906:Antibodies / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D005779:Immunodiffusion / Q000379:methods; D007070:Immunoglobulin A / Q000032:analysis; D007674:Kidney Diseases / Q000097:blood; D007841:Latex Fixation Tests / Q000379:methods; D008107:Liver Diseases / Q000097:blood; D011863:Radioimmunoassay
D000510:Alpha-Globulins; D000906:Antibodies; D007070:Immunoglobulin A; C016001:alpha-1-microglobulin