Inhibitors in the Swedish population with severe haemophilia A and B: a 20-year survey
Article first published online: 2 JAN 2007
Volume 91, Issue 8, pages 910–914, August 2002
How to Cite
Knobe, K., Sjörin, E., Tengborn, L., Petrini, P. and Ljung, R. (2002), Inhibitors in the Swedish population with severe haemophilia A and B: a 20-year survey. Acta Paediatrica, 91: 910–914. doi: 10.1111/j.1651-2227.2002.tb02854.x
- Issue published online: 2 JAN 2007
- Article first published online: 2 JAN 2007
- Received Nov. 5, 2001; revision received March 22, 2002; accepted 12 April 2002
- Factor VIII;
- factor IX;
- haemophilia A;
- haemophilia B;
Aim: To survey the entire population (n= 116) afflicted with severe haemophilia A or B born in Sweden over a 20-y period (1980–1999), and to examine the epidemiological, genetic and clinical aspects of development of inhibitors to factors VIII and IX (FVIII/FIX). Methods: One hundred of the subjects had haemophilia A and 16 had haemophilia B. All of these subjects had received prophylactic treatment and had a check-up of inhibitor status at least twice a year. Sixty-one were born between 1980 and 1989 and 55 between 1990 and 1999. Results: Nineteen percent (19/100) of those with haemophilia A and 37% (6/16) with haemophilia B developed inhibitors at 12–18 mo of age, after exposure to FVIII/FIX concentrates for an average of 14 d in the case of haemophilia A and 16 d in haemophilia B. All patients with inhibitors carried mutations that impaired protein synthesis. The high incidence of FIX inhibitors may have been due to the large number of complete deletions (13%) in the Swedish haemophilia B population. Patients with haemophilia A showed no significant increase (p= 0.65) in incidence of inhibitors (n= 10/48, total incidence 21%) in the 1990s, when they were treated mainly with recombinant products, as compared to the 1980s (n= 9/52,17%), when they received intermediate/high-purity plasma-derived concentrates.
Conclusion: Our population-based study verifies that genotype has a general impact on the incidence of FVIII/FIX inhibitors, and that recombinant FIII/FIX concentrates are not a predisposing factor for inhibitor development.