Statistics
Categorical data were compared using the χ2 test. The significance of group comparisons was determined using either the Mann-Whitney test or Kruskal-Wallis test for multiple comparisons, as appropriate. Error bars represent mean ± SEM. Normal Gaussian distribution of continuous variables was determined using the D’Agostino-Pearson omnibus normality test. Correlations between cytokines and continuous variables were determined with either the Pearson correlation coefficient for data with a normal distribution or the nonparametric Spearman correlation for data with a non-Gaussian distribution. For all analyses, p < 0.05 was considered significant. All calculations were performed using GraphPad Prism 7.0 (GraphPad Software, San Diego, CA).