Factor XIII levels and factor XIII B subunit polymorphisms in patients with venous thromboembolism.

BACKGROUND

The association of plasma factor XIII (FXIII) level with venous thromboembolism (VTE) is still controversial and the effect of sex and FXIII B subunit (FXIII-B) polymorphisms in this respect have not been explored.

OBJECTIVES

1/ To determine FXIII activity and antigen levels in patients with a history of VTE and how they are influenced by sex and FXIII-B polymorphisms. 2/ To explore the association of FXIII levels and FXIII-B polymorphisms with the risk of VTE.

METHODS

218 VTE patients and equal number of age and sex matched controls were enrolled in the study. FXIII activity was measured by ammonia release assay; FXIII-AB and FXIII-B levels were determined by ELISAs. FXIII-B polymorphisms were identified by RT-PCR using melting point analysis.

RESULTS

Adjusted FXIII activity and FXIII-AB antigen levels were significantly higher in females with a history of VTE than in the respective controls. FXIII-B levels were significantly lower in male VTE patients than in controls. FXIII-AB antigen levels in the upper tertile increased the risk of VTE in females (adjusted OR: 2.52; CI: 1.18-5.38). Elevated FXIII-B antigen level had a protective effect only in males (adjusted OR: 0.19; CI: 0.08-0.46). FXIII-B Intron K c.1952+144 C>G polymorphism significantly lowered FXIII activity, FXIII-AB and FXIII-B antigen levels in both groups. FXIII-B polymorphisms did not influence the risk of VTE.

CONCLUSIONS

In VTE patients the changes of FXIII level and their effect on the risk of VTE show considerable sex-specific differences. Intron K polymorphism results in decreased FXIII levels, but does not influence the risk of VTE.