My son was diagnosed with Cyclical Neutropenia in 1997. Every time his neutrophil count goes down he gets the mouth ulcers but also gets symptoms similar to ulcerative colitis. These symptoms are what lead us to the diagnosis of Neutropenia. He was given G-CSF and this actually lowered the count; even though the count in the marrow was high, it was not making it to the blood. The only thing that relieves the symptoms of the Colitis is Prednisone, which seems to keep the CN at bay... has anyone ever heard of this connection between Neutropenia and Ulcerative Colitis??? Has anyone had this kind of reaction to the G-CSF?