An IgG complexed form of vitamin B12 is a common cause of elevated serum concentrations.
Clin Biochem
; 43(1-2): 82-8, 2010 Jan.
Article
em En
| MEDLINE
| ID: mdl-19744472
ABSTRACT
OBJECTIVES:
To report detailed investigations in a case of elevated serum B(12) due to the presence of an IgG-B(12) complex, to determine the prevalence of this phenomenon and to review the literature. DESIGN ANDMETHODS:
431 samples with elevated B(12) (median 1250 ng/L, range 901-114,480 ng/L) were treated with polyethylene glycol to precipitate immunoglobulin complexes. Samples with >50% of precipitable B(12) (PPB(12)) were further investigated by protein G adsorption, gel filtration chromatography and measurement of B(12) on different analytical platforms.RESULTS:
Median PPB(12) was 22.6%, but in 35 samples (8.1%), median PPB(12) was more than 50%. Investigation of 27 of these samples with protein G-Sepharose confirmed the presence of an IgG-B(12) complex in 24, and in 15 cases, B(12) fell to within the reference range. After treatment of serum with reagents releasing B(12) from binding proteins, immunoreactivity co-eluted with free B(12). Immunoreactivity of the IgG-bound form of B(12) was confirmed using five B(12) assays in common use in the UK.CONCLUSIONS:
At least 8% of samples with elevated vitamin B(12) contain an immunoglobulin complexed form of circulating B(12); this possibility should be considered in the interpretation of results.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Vitamina B 12
/
Complexo Vitamínico B
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Imunoglobulina G
/
Complexos Multiproteicos
Tipo de estudo:
Risk_factors_studies
Limite:
Female
/
Humans
/
Middle aged
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article