Paediatric age-dependent serum transferrin isoform distribution studied by HPLC.

BACKGROUND

Human serum transferrin shows different transferrin isoforms with e.g. a varying amount of glycosylation, resulting in asialo-, mono-, di-, up to octasialotransferrin. We wanted to examine whether there are age-dependent differences in this transferrin isoform distribution.

METHODS

Serum samples from a total of 126 paediatric patients (mean/median/minimum/maximum: 6.8/6.0/0.5/14 years) grouped in seven age groups (<2 years, 3-4 years, up to 13-14 years) were analyzed on an HPLC (Recipe Chemicals & Instruments GmbH, Munich, Germany). Means, medians and percentiles were computed for each transferrin isoform and tested for statistically significant differences between the age groups.

RESULTS

CDT corresponded to disialotransferrin (since asialo- and monosialotransferrins were not detectable) and did not show statistically significant differences between the 7 age groups. The latter is also true for trisialo- and tetrasialotransferrin whereas pentasialotransferrin shows a statistically significant decrease with age.

CONCLUSIONS

We suggest that age-independent decision limits, e.g. the 95% percentiles for disialotransferrin (1.1%) and trisialotransferrin (5.3%), can be used for the differentiation between normal and increased fractions of these isoforms until paediatric reference ranges have been established. The presence of asialo- and monosialotransferrin in paediatric serum should be considered as abnormal.