Long-term prophylaxis in patients with severe congenital factor XIII deficiency is not complicated by inhibitor formation

Congenital factor XIII (FXIII) deficiency is a rare bleeding
disorder accompanied by a variety of bleeding events.
Severely deficient patients require regular replacement
therapy. With development of FXIII concentrate, the risk of
viral infections transmitted by fresh frozen plasma and
cryoprecipitate is diminished, but the possibility of inhibitor
development remains a challenging issue in the
management of these patients. The aim of this study was to
assess FXIII inhibitor development in Iranian patients with
FXIII deficiency (FXIIID). This study enrolled 50 (30 women
and 20 men) patients with severe congenital FXIIID from
southeast Iran who underwent long-term (more than 4 year
or more than 50 injections) prophylaxis with FXIII
concentrate (Fibrogammin P, Dade Behring, Marburg,
Germany). We evaluated plasma FXIII activity and FXIII
inhibitor on day 28 after the last prophylaxis administration.
The method for investigation of FXIII inhibitor was based on
Bethesda
AQ5 assay. The mean age of the study population was
13.8 W 8.3 years. The minimum and maximum FXIII activity
levels were less than 1–4.5% (mean W SD, 2.6 W 0.7%). Our
investigations showed that all patients with severe form of
FXIIID (FXIII activity <5%) were treated without inciting
inhibitor development.
Despite long-term prophylaxis in the studied patients, none
was found to have developed FXIII inhibitors. Blood Coagul
Fibrinolysis 27:000–000 Copyright 2016 Wolters Kluwer
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