Figure 4.

Peptide immunotherapy is associated with allergen-specific hyporesponsiveness and the induction of IL-10. (A) Cat-allergic asthmatic subjects (n = 6) were challenged intradermally with a mixture of 12 peptides (5 μg each) from the sequence of Fel d 1 or vehicle alone. Lung function was measured by spirometry for 6 hours. Challenges were separated by 14 days or more. Challenge with vehicle (circles) did not significantly modify forced expiratory volume in one second (FEV₁). Initial peptide challenge (squares) resulted in an isolated LAR that significantly differed from baseline (P = 0.02 area under the curve; AUC). A second challenge (triangles) with the same dose of peptide was associated with an attenuated or absent LAR. Values are mean of 6 individuals with standard error. (B) Cat-allergic asthmatic subjects underwent intradermal allergen challenge (volar aspect of the forearm) before and after administration of a mixture of 11 peptides in incremental divided doses. Peptide treatment significantly reduced the magnitude of the cutaneous late-phase reaction. (C) Treatment of 16 cat-allergic asthmatic individuals with a mixture of 12 peptides (incremental divided doses) resulted in elevated production of IL-10 by peripheral blood mononuclear cells at both 4–6 weeks and 3–9 months after the completion of treatment. Data presented as median and interquartile range.