Flow cytometry data was analyzed in FlowJo v.9.8.2 (Treestar; Ashland, OR, USA). Expression of surface markers was compared between Th subsets using the Friedman chi-square test; with post-hoc pairwise comparisons made using the Wilcoxon related samples rank test; Bonferroni adjusted p-values are reported. T cell populations were compared between S. mansoni-infected and uninfected men by Mann-Whitney U test. Analysis of Th17 cell polyfunctionality was performed using Boolean gating in FlowJo software, and polyfunctionality compared between S. mansoni-infected and uninfected men with a chi-squared distribution (1000 permutations of pies) using SPICE v5.35 software (Exon, National Institute of Allergy & Infectious Diseases)[63 (link)]. Post-hoc comparisons between functional Th17 subsets were made using related samples Wilcoxon rank test. Excel v.14.4.8 (Microsoft; Redmond, WA, USA) was used prior to statistical testing, and statistical tests were run using SPSS v.20.0 for Mac (IBM; New York, NY, USA). Based on previous foreskin T cell studies [26 (link), 62 (link), 64 (link)], a sample size of 34 men provided 80% power to detect a difference of one standard deviation in the proportion of either foreskin or blood CD4 T cells that were Th17 cells (α = 0.05).
Free full text: Click here