README:
The details of the data collection methods, data QC and processing, and analyses are described in the associated manuscript. Briefly, peripheral blood samples were collected at age 18 among a subset of participants in the Isle of Wight birth cohort and used for genome-scale DNA methylation (DNA-M) measurement with the Illumina Infinium HumanMethylation450K beadchip (Illumina, Inc., CA, USA). Genome Studio was used for QC, peak correction was performed via Bioconductor IMA, and batch effects were removed via ComBat. Exclusion of probes with detection P-values greater than 0.01 in more than 10% of samples, probes on the X or Y chromosomes, and probes containing potential SNPs within the binding region, yielded 254,460 CpG sites for analyses. Atopy status was defined as having at least one positive skin prick (SPT) to a battery of common allergens. High IgE was defined as having total serum IgE greater than or equal to 200 kU/L. Cell proportions of major leukocyte components (CD4T, CD8T, Monocytes, Natural killers, B-cells, and Granulocytes) were estimated from DNA-M via the Houseman method. Two datasets are associated with this manuscript. "Stage1_Data.csv" includes all data used for the recursive random forest data reduction analyses. "Stage2_Data.csv" includes all data used for regression analyses of atopy status and high IgE.

Citation:	
Everson TM, Lyons G, Zhang, H, Soto-Ram¡rez, N et al. DNA methylation loci associated with atopy and high serum IgE: a genome-wide application of recursive Random Forest feature selection. Genome Medicine 2015, in press.
Organism:	Homo sapiens
Array Platform: Illumina Infinium HumanMethylation450K beadchip

Title:		Stage1_Data
Summary:	Cross-sectional genome-scale analysis of peripheral blood leukocytes for DNA-M variations at CpG sites associated with atopy status (at least one positive SPT) among females at age 18 years.
Sample Count: 	242
Contents [Column Number; "Column Header"; Column Description]:
		Col 1; "ID"; Sample ID Number
		Col 2-254461; "cgXXXXXXXX"; Methylation Data
		Col 254462; "ATOPIC_18"; Atopy status at age 18

Title:  	Stage2_Data
Summary:	Cross-sectional analysis of candidate CpG sites in a pooled sample (females from Stage1_Data combined with 120 males). 62 candidate CpG sites were selected from Stage-1 data reduction. Given the possibility of confounding from cellular heterogeneity or sex-differences, we adjusted for estimated proportions of major leukocyte components and for sex in analyses of atopy and high IgE.
Sample Count:	362
Contents [Column Number; "Column Header"; Column Description]:
		Col 1; "ID"; Sample ID Number
		Col 2; "SEX_18"; Sex (2=female, 1=male)
		Col 3; "ATOPIC_18"; Atopy status at age 18
		Col 4; "IGE_18"; High IgE status at age 18
		Col 5; "Bcell"; estimated proportion of B cells in the blood sample
		Col 6; "CD4T"; estimated proportion of CD4T cells in the blood sample
		Col 7; "CD8T"; estimated proportion of CD8T cells in the blood sample
		Col 8; "Mono"; estimated proportion of Monocytes in the blood sample
		Col 9; "NK"; estimated proportion of Natural Killer cells in the blood sample
		Col 10; "Gran"; estimated proportion of Granulocytes in the blood sample
		Col 11-72; "cgXXXXXXXX"; Methylation Data