Importantly, the cell proxy analysis only takes into account the relative percentage of various cell types, but not the overall white blood cell (WBC) count. Where available, prepartum WBC counts and proportions of lymphocytes, granulocytes and monocytes were obtained from complete blood count (CBC) data (N=17 women). CBC derived total WBC counts were negatively correlated with the proxy-derived monocyte to non-monocyte ratio (Spearman’s ρ= −0.7, P=0.02), suggesting that the decreased cell-type ratio observed in the prepartum depressed group may be indicative of elevated WBC counts and depression-associated inflammation. This effect appeared to be driven by a positive correlation of WBC count with granulocyte proportion (Spearman’s ρ=0.92, P=2.2×10−16), which is consistent with the above-cited elevations in granulocyte levels with depression.29 The ratio of CBC-derived monocyte to non-monocyte (lymphocytes and granulocytes) ratio did not correlate with those derived by DNA methylation proxy (Spearman’s ρ=0.24, P=0.36). We limited the analysis to only those 11 samples where CBC data was derived from within the same trimester as the blood draw used for microarray analysis and observed a significant correlation (Spearman’s ρ=0.66, P=0.044). We attempted
