Summary
In a study of 170 haemophilia A patients, 43 were found to have an inhibitory effect;
seven had anti-factor VIII inhibitors (a-fVIII) (A), 18 had lupus anticoagulants (LAs)
with a strong (B: 12) or weak (C: 6) time-dependent effect and 18 had no time-dependent
LAs (D). The a-fVIII showed a neutralizing effect only against factor VIII and negative
diluted Russell viper venom time (dRVVT). The LAs were diagnosed by dRVVT; the Staclot®
LA agreed with the dRVVT. During the study, three patients changed from an a-fVIII
to an LA pattern; they also modified their clinical response.
Our prevalence of a-fVIII was low (4%) and we found 21% of LA, with a high (50%) prevalence
of time-dependent inhibition. This pattern raises the possibility of the coexistence
of LA and a-fVIII, stressing the need to develop specific tests to identify a-fVIII
and LA.
