there have been several studies showing that neupogen use does not lead to rejection--rejectio0n is more related to lymphocytes rather than neutrophils.
frankly, we dont really know how interferon works to battle HCV--it boosts the immune system in some manner and is unrelated to its affects on any WBC.
Which one of those goes after the HCV? It seem odd that interferon lowers WBCs yet also HCV. Or is the lymphocytes that attach the HCV? Does INF stimulate the lymphocytes to do that?