Aberrant glycosylation of Igg heavy chain in multiple myeloma.
Although the majority of eukaryotic proteins are glycosylated, there is a dearth of knowledge regarding protein sugar moieties and their changes in disease. Most multiple myeloma cases are characterized by production of monoclonal immunoglobulins (Ig). We studied galactosylation and sialylation of IgG heavy chains in 16 patients with IgG myeloma using lectin blotting and densitometry. In comparison to age and sex matched controls, galactosylation was reduced in multiple myeloma (median 317 vs. 362, range 153-410 vs. 309-447 relative units, p = 0.015, Student's t-test). Sialylation was stage dependent; samples from patients with stage IIA had lowest amounts of sialic acid, IIIA intermediate and IIIB highest (142.6 vs. 185.9 vs. 248.5 relative units, correlation coefficient r = 0.55). Both galactosylation and sialylation levels were independent of age, sex, treatment type, response to treatment, disease duration and IgG and b2 microglobulin concentration. These data indicate that multiple myeloma is characterized by aberrant immunoglobulin glycosylation.
Aurer
Igor
I
Division of Hematology, Department of Internal Medicine, University Hospital Center and Medical School, Zagreb, Croatia. aurer@mef.hr
Lauc
Gordan
G
Dumić
Jerka
J
Rendić
Dubravko
D
Matisić
Danica
D
Milos
Marija
M
Heffer-Lauc
Marija
M
Flogel
Mirna
M
Labar
Boris
B
D000328:Adult; D000368:Aged; D005260:Female; D005690:Galactose / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000276:immunology*; D019158:N-Acetylneuraminic Acid / Q000378:metabolism
D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D019158:N-Acetylneuraminic Acid; D005690:Galactose