title: Effect of Mycobacterium vaccae on cytokine responses in children with atopic dermatitis.
abstract: The increasing prevalence of atopic diseases over the last few decades is thought to be due to reduced exposure to environmental microbes that normally down-regulate allergic responses (hygiene hypothesis). We have shown previously that administration of the environmental microbe Mycobacterium vaccae ameliorates atopic dermatitis in school-age children at 3 months post-treatment. The present study tested the hypothesis that M. vaccae suppresses Th2-type cytokine activity and increases transforming growth factor (TGF)-beta(1) immunomodulatory activity in these children. Interleukin (IL)-4, IL-5, TGF-beta(1) and interferon (IFN)-gamma activity were assessed in resting and stimulated peripheral blood mononuclear cells (PBMC) isolated from 12 of the children who received M. vaccae in our original clinical trial. A cDNA expression array was used to examine a broader range of cytokine pathway transcripts. There were no significant changes in either Th2-type or TGF-beta(1) activity. A 5- to 10-fold increase in Th1-type activity was found at 1 month post-M. vaccae administration (P < 0.05), but it had returned to baseline by 3 months. The results do not support the hypothesis that M. vaccae reduces Th2-type or increases TGF-beta(1) activity of PBMC isolated from children with atopic dermatitis. The transient surge in IFN-gamma at 1 month is unlikely to explain any improvement in eczema score at 3 months.
authors.affiliation: North West Lung Research Centre, Wythenshawe Hospital, Manchester, UK. ehadley@fs1.with.man.ac.uk
authors.forename: E A
authors.initials: EA
authors.lastname: Hadley
authors.forename: F I
authors.initials: FI
authors.lastname: Smillie
authors.forename: M A
authors.initials: MA
authors.lastname: Turner
authors.forename: A
authors.initials: A
authors.lastname: Custovic
authors.forename: A
authors.initials: A
authors.lastname: Woodcock
authors.forename: P D
authors.initials: PD
authors.lastname: Arkwright
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000276:immunology*; D004270:DNA, Circular / Q000276:immunology; D003876:Dermatitis, Atopic / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D015848:Interleukin-5 / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology; D009161:Mycobacterium / Q000276:immunology*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D016212:Transforming Growth Factor beta / Q000276:immunology; D015854:Up-Regulation / Q000276:immunology
chemical_list: D016207:Cytokines; D004270:DNA, Circular; D015848:Interleukin-5; D016212:Transforming Growth Factor beta; D015847:Interleukin-4; D007371:Interferon-gamma