The ts (qt_de.ts) file for German in Qt5.2.1 looks like this:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE TS>
<TS version="2.0" language="de">
<dependencies>
<dependency catalog="qtbase_de"/>
<dependency catalog="qtscript_de"/>
<dependency catalog="qtquick1_de"/>
<dependency catalog="qtmultimedia_de"/>
<dependency catalog="qtxmlpatterns_de"/>
</dependencies>
</TS>

lrelease runs without an error but it does not resolve the dependencies so the generated qm file does not contain the translations.