- Use of chronic corticosteroids, hydroxyurea, or immunomodulating agents (e.g. interleukin-2, interferon-alpha or gamma, granulocyte colony stimulating factors, etc.) within 30 days prior to study entry. NOTE: Recent or current use of inhaled steroids is not exclusionary. If subjects are prescribed a brief course of oral corticosteroids, the use should be limited to less than 7 days. Use of steroids before apheresis and immune assessment blood draws should be discouraged as it will affect white blood cell function.