Asthma has been described as an eosinophilic bronchitis driven by interleukin-4(IL-4) and interleukin-5 (IL-5). IL-4 and IL-452, the IL-4 receptor agonist, have not been distinguished previously. Quantification of in vivo IL-5 mRNA levels have been confounded by housekeeping gene expression which differs between and within asthmatics and normals (submitted). Hypothesis: IL-4 and IL-5 expression, quantitated by competitive RT-PCR which is not confounded by housekeeping gene expression, discriminates between normals, atopies and asthmatics. Methods: Quantitative competitive RT-PCR was conducted on RNA extracted from the bronchoalveolar lavage (BAL) of 25 normals (13 atopic) and 82 asthmatics (67 atopic). Results: IL-4 and IL-482 mRNA levels were not different between any group and were also not affected by steroid use. IL-4 and IL482 levels were positively correlated (p = 0.0001, r2 = 0.31). IL-5 mRNA expression in asthmatics on low dose (<500 μg BDP/day) inhaled corticosteroids (ICS) was significantly lower than those not on ICS (least squares mean (LSM) 179 vs 100 copiesVg RNA, p = 0.04). IL-5 mRNA levels in non-atopic normals were significantly less than both atopic normals (LSM 60 vs 142 copies/,ng RNA, p=0.017) and atopic asthmatics (LSM 60 vs 149 copies/μg RNA, p=0.007). Conclusions: Levels of IL-4 and IL-482 mRNA suggest coordinated transcription. IL-4 mRNA did not differ with asthmatic or atopic status, suggesting regulation of expression subsequent to transcription. IL-5 mRNA levels are upregulated with atopy and asthma.
|Issue number||SUPPL. 1|
|Publication status||Published - 1 Dec 1999|
- Competitive rt-pcr