All patients showed clinically significant improvement after 12 weeks of the systemic INF-gammatherapy. There was no clinical aggravation during the therapy period and the follow-up 4 weeks without the therapy. But the recurrence rate in the 12 weeks after discontinuing the therapy was about 40%. Eosinophil counts and eosinophil fractions were significantly decreased after the therapy. And, eosinophil counts and eosinophil fractions were increased in clinically aggravated patients during the 12 weeks of off-therapy.