Decreased Clotting Factor Activity (VIII, IX, XI, and XII) due to Inhibitors with Lupus-like Activity in Childhood

Conclusions

The lupus sensitive Platelin LS reagent showed prolonged aPTT in 25 investigated plasmas compared to the lupus insensitive STA APTT Kaolin reagent.

In all investigated plasmas the inhibitor evidence with the plasma mixing study was positive according to immediate inhibition.

With selected LA confirmatory tests 15 plasmas with different sensitivity were recognized as LA positive and 10 plasmas were not confirmed as LA positive. It can not be excluded, that other LA confirmatory tests will show positive results.

The “lupus sensitive” Platelin LS reagent should be described as “inhibitor sensitive”.

The inhibitor effect demonstrated a wide range according to the activities of the single clotting factors and had an interfering as well as an inactivating effect.

The patients did not show clinical features of thromboembolic incidents.

Despite decreased activities of single factors, increased bleeding was not found.

Observations about clinical symptoms and clotting analyses are in progress.