Effects of Different Concentrations of Dexamethasone and Methylprednisolone on Immunofunctions of Periphe-ral Blood Mononuclear Cells in Children with Asthma

Objective To observe the effects of different concentrations of dexamethasone(DEX) and methylprednisolone(MP) on the Th1/Th2 cytokines secretion in the peripheral blood mononuclear cells(PBMC) in children with asthma.Methods Fifteen children with asthma and 14 healthy children who visited in the Children′s Hospital of Chongqing Medical University from Jun.2001 to Jun.2002 were selected.Five millilitre fasting blood samples were collected,and PBMC were isolated using Ficoll-Hypaque density gradient centrifugation.The samples were divided into several groups,including healthy control group,asthma control group,10-7 mol·L-1DEX group,10-8 mol·L-1 DEX group and 10-9 mol·L-1 DEX group,10-7 mol·L-1MP group,10-8 mol·L-1 MP group and 10-9 mol·L-1 MP group.PBMC were incubated with phytohemagglutinin and DEX or MP in the concentration of 10-7mol·L-1,10-8mol·L-1and 10-9mol·L-1respectively.After 48 hours incubation,supernatant was harvested to determine levels of gamma interferon(IFN-γ),IL-4,IL-10 and IL-12 by ELISA,and the inhibition ratios of different concentrations of DEX and MP on the cytokines were calculated.Results 1.IL-4 level in children with asthma was significantly increased than that in the healthy children(P0.05),and the ratio of IFN-γ and IL-4 statistically declined(P0.05).There was no significant difference of IFN-γ,IL-10 and IL-12 levels beween the 2 groups.2.DEX and MP inhibited significantly the secretion of IFN-γ,IL-4,and IL-12,and had mild inhibition on IL-10,which was significantly weaker in children with asthma compared with that in the healthy children(Pa0.05).3.DEX and MP inhibited the secretion of IL-4 in a concentration-dependent manner.In the concentration of 10-9mol·L-1,MP still inhibited the secretion IL-4,while DEX promoted IL-4 level,and there was significant difference between the 2 groups(P0.05).If the balance of Th1/Th2 was represented by IFN-γ/IL-4,MP could restore the imbalance(P0.05).Conclusions DEX and MP can inhibit the secretion of Th1/Th2 cytokines,but MP can restore the imbalance of Th1/Th2,which suggests that MP is better in the therapy for asthma.