A new approach to quantitate carbohydrate-deficient transferrin isoforms in alcohol abusers: partial iron saturation in isoelectric focusing/immunoblotting and laser densitometry.
Carbohydrate-deficient transferrin (Tf) represents a significant advance over previous markers of alcohol abuse. Isoelectric focusing (IEF) analysis of affinity-purified Tf, under conditions of total iron saturation, identifies a major isoform at pI 5.4 in both normal consumers and alcohol abusers; three additional Tf isoforms (pI 5.6, 5.7, and 5.8) are associated with alcohol abuse. Under conditions of partial iron saturation, IEF analysis of affinity-purified Tf reveals up to seven isoforms (pI range 5.3-6.0) common to normal consumers and alcohol abusers; three additional transferrin isoforms (pI range 6.1-6.3) are present in 68% (15/22) of the alcohol abuser specimens, but in only 8% (1/12) of the specimens from normal consumers and in none of the three specimens from abstainers. These three diagnostic bands comigrate with a set of defined Tf isoforms: human iron-free Tf containing two sialic acid residues, human sialic acid-free Tf with one iron molecule, and human sialic acid-free, iron-free Tf. Serum specimens from normal consumers and alcohol abusers, analyzed for Tf isoforms by an IEF-immunoblot method under conditions of partial iron saturation, expressed Tf isoforms similar to those found using affinity-purified Tf in standard IEF. Visual examination of the immunoblots reveals the diagnostic bands in 67% (32/48) of patients with histories of sustained alcohol abuse compared with only 17% (8/48) of the normal consumers. Scanning densitometry and volume integration analysis of the immunoblots representative of normal consumer and alcohol abuser populations results in mean (+/- SE) values of 4.1 +/- 0.8 and 19.3 +/- 3.6 units, respectively (p < 0.0002).
Bean
P
P
Specialty Laboratories, Inc., Santa Monica, CA 90404-3900.
Peter
J B
JB
D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000097:blood* / Q000175:diagnosis; D002846:Chromatography, Affinity; D003720:Densitometry; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007501:Iron / Q000097:blood; D007525:Isoelectric Focusing; D008297:Male; D008875:Middle Aged; D014168:Transferrin / Q000031:analogs & derivatives* / Q000032:analysis / Q000145:classification
D014168:Transferrin; C056759:carbohydrate-deficient transferrin; D007501:Iron