Many physicians have begun using haematopoietic growth factors “off-label” to manage haematological side effects in patients with chronic hepatitis C. A recent French study reported that 46% of clinicians treating HCV infection used erythropoietic agents and granulocyte colony stimulating factor but there was considerable variation in the molecules and regimen used.12 Unfortunately, no official guidelines currently exist, and many issues remain unresolved. The gene discussed is CSF3; the disease is chronic hepatitis C virus infection.