DNA MICROARRAY ANALYSIS OF TRANSFORMING GROWTH FACTOR-β AND RELATED TRANSCRIPTS IN NASAL BIOPSIES FROM PATIENTS WITH ALLERGIC RHINITIS
Decreased activity of anti-inflammatory cytokines like transforming growth factor (TGF)-β may contribute to allergic inflammation. In vivo effects of TGF-β-effects are difficult to infer from local concentrations, since TGF-β-effects depend on a complex system of regulatory proteins and receptors. Instead the effects of TGF-β might be inferred by examining TGF-β-inducible transcripts. In this study DNA microarrays were used to examine local expression of TGF-β, TGF-β-regulatory and -inducible transcripts in nasal biopsies from patients with symptomatic allergic rhinitis and healthy controls. In addition, nasal fluids were analysed with cytological and immunological methods. Nasal fluid eosinophils, albumin, eosinophil granulae proteins and IgE, but not TGF-β, were higher in patients than in controls. DNA microarray analysis of nasal mucosa showed expression of transcripts encoding TGF-β, TGF-β-regulatory proteins and -receptors at variable levels in patients and controls. By comparison, analysis of 28 TGF-β-inducible transcripts indicated that 23 of these had lower measurement values in patients than in controls, while one was higher, and the remaining four were absent in both patients and controls. In summary, TGF-β and a complex system of regulatory genes and receptors are expressed in the nasal mucosa. Low expression of TGF-β-inducible transcripts may indicate decreased TGF-β activity in allergic rhinitis. DNA microarray analysis may be a way to study cytokine effects in vivo.