ABSTRACT
The thrombin activatable fibrinolysis inhibitor (TAFI) influences the pathways regulating
fibrin formation and deposition. The enormous TAFI plasma level variability present
in adults may be explained by a combination of two polymorphisms in the TAFI gene (+1542C>G; 505G>A). We aimed to correlate these two polymorphisms with plasma
TAFI antigen concentrations in healthy children and pediatric oncology patients with
and without venous thrombosis who were supplied with Broviac central venous catheters.
Polymorphisms were detected by restriction fragment length polymorphism (RFLP) analysis
of polymerase chain reaction (PCR) amplification, whereas TAFI concentration was determined
using a commercial enzyme-linked immunosorbent assay (ELISA). Samples from 57 controls
and 67 pediatric patients (11 venous thrombotic complications) were studied. TAFI
levels in healthy children and patients were not influenced by gender or age. Compared
with the 505GG carriers (wild type), 505AA carriers as well as heterozygous 505GA
carriers each exhibited significantly higher TAFI antigen concentrations. In contrast,
the lowest TAFI levels were detected in homozygous carriers of the +1542GG polymorphism.
A combination of the genotype 505AA (homozygous carrier) and +1542CC (wild type) was
present in 13 probands and resulted in the highest TAFI levels. Although in oncologic
patients the risk of thrombosis was markedly increased by the heterozygous factor
V 1691G>A mutation, the two TAFI polymorphisms investigated exerted no thrombogenic influence.
KEYWORDS
TAFI - polymorphism - thrombosis - oncology - children