[Lectin-reactive alpha-fetoprotein in tyrosinaemia type I]

Despite the introduction of NTBC into the treatment of tyrosinaemia type I (TT1) and a considerable improvement in the outcome of these patients, the principal risk of developing hepatocellular carcinoma (HCC) in this metabolic disorder remains mainly in those children with late introduction of NBTC after the second year of life. Serial total alpha-Fetoprotein (AFP) levels are used to evaluate the individual risk to develop malignant changes. A failure of AFP to decrease on adaequate treatment or a secondary increase after a period of falling levels have been an indication for liver transplantation. Lectin-reactive alpha-Fetoprotein is a recently described marker to distinguish hepatocellular carcinoma from benign liver disease in adult cirrhotic patients.

To investigate if the analysis for Lectin-reactive alpha-Fetoprotein would lead to earlier detection of HCC compared to a judgement based on the evolution of standard total AFP alone.

We report the analysis of 12 patients with TTI and histologically proven HCC. There of 5 were diagnosed under one year of age, but NTBC treatment was started between 2 years 3 month and 7 years of age except in one case in which NTBC was introduced when the diagnosis of TTI was made. The remainder of the patients cover up to the age of 15 years. All patients had been treated with NTBC.

Lectin containing agarose gel for AFP electrophoresis leads to AFP separation according to different affinities of the varying carbohydrate chains of AFP to lectins.

AFP subfractions could be identified in all 12 patients. In 6 patients the L3-AFP rose before the total AFP. In 3 patients the rise in L3-AFP was consistent with the rise of the total AFP and in 3 patients the L3-AFP was raised after the total AFP or did not increase at all.

We were able to identify 6 out of 12 patients who had an early increase of L3-AFP before they developed a change in total AFP levels. The clinical significance of these early changes need to be determined. Lectin-affinity electrophoresis may have a potential role as an additional tool that may help to discriminate benign liver disease from HCC in TTI.

We suggest the further evaluation of lectin-reactive AFP in TTI.