Effect of filgrastim (recombinant human granulocyte colony stimulating factor) on IgE responses in human asthma: a case study.

Rationale: The role of peripheral blood progenitor cell mobilization on Immunoglobulin E (IgE) responses has not been studied.

Methods: Distributions of blood lymphocytes (CD4+, CD8+, CD8+CD60+, CD19+, CD23+, CD16/56+, CD25, CD45RA+, CD45RO+, CD34+), and levels of serum immunoglobulins (IgM, IgG, IgA, IgE) were studied in an allergic asthmatic serum IgE+ (181IU/mL) adult (m/45 y/o) donor undergoing routine stem cell mobilization protocol (American Society of Hematology) before (day-30), during (day 4), and after (1 wk post last dose) filgrastim (subcutaneous, 480 mcg, 2qd) treatment (flow cytometry, nephelometry, UniCAP Total IgE Fluoro enzyme immunoassay).

Results: On day 4 of filgrastim treatment, numbers of CD8+CD60+T cells and CD23+ blood cells dramatically increased (98% and 240% respectively) compared with pre treatment. In contrast on day 4 of treatment, serum IgE levels decreased (>50%) compared with pre treatment. CD8+CD60+T cells and CD23+ blood cells and serum IgE levels approached pre-treatment levels at 1 week post treatment.

Conclusions: Filgrastim treatment transiently increases numbers of CD8+CD60+T and CD23+ expressing cells, which are known to regulate human IgE responses, while also transiently suppressing ongoing IgE responses. These results suggest that filgrastim affects IgE related responses, and may be useful in modulating allergic responses.