[Expression of interleukin-5 and interleukin-10 and their relationship in asthma]

To explore the expression of interleukin-5(IL-5) and interleukin-10(IL-10) and their relationship in asthma, we measured the cells in bronchial alveolar lavage fluid(BALF) of guinea pigs, and examined the expression of IL-5 mRNA and IL-10 mRNA of bronchial tissue by reverse transcription polymerase chain reaction(RT-PCR) in control group(Group C, n = 10), asthmatic group(Group A, n = 11) and dexamethasone treatment group(Group B, n = 10). The results showed that the eosinophil(EOS) percentage and the expression of IL-5 mRNA were significantly higher in Group A[(48.64 +/- 17.8)%, (106.91 +/- 20.09)% respectively] than that in Group C[(15.10 +/- 11.48)%, (62.60 +/- 13.84)%] and Group B[(28.4 +/- 10.32)%, (75.30 +/- 10.70)%]. In contrast, the IL-10 mRNA expression in Group A[(47.5 +/- 5.3)%] was obviously lower compared with that in Group C[(101.2 +/- 4.2)%] and Group B[(80.1 +/- 8.3)%]. The correlation between the expression level of IL-5 mRNA and percentage of EOS was positive(r = 0.924, P < 0.01), whereas the IL-5 mRNA was negatively correlated with IL-10 mRNA expression(r = -0.731, P < 0.01).

IL-5 and EOS might play a role in the pathogenesis of asthma, the inhibition of IL-10 mRNA expression may cause the increase of IL-5 expression in asthma. The beneficial effects of corticosteroid treatment in asthma may partly result from increasing IL-10 mRNA expression and inhibiting IL-5 mRNA expression.