Controleer de documenten http://php.net/manual/en/ref.pdo -mysql.php .
In principe heb je nodig:
PDO::MYSQL_ATTR_LOCAL_INFILE => true
Instellen op instantiatie.
Voorbeeld:
$conn = new \PDO("mysql:host=$server;dbname=$database;", "$user", "$password", array(
PDO::MYSQL_ATTR_LOCAL_INFILE => true,
));