In preeclampsia, a positive correlation was demonstrated between the percentage of Th22 and Th17 lymphocytes and the plasma IL-22 concentration and the percentage of Th22 cells; at the same time, CD4+IL-17A+IL-22+ cells were observed more frequently, although the plasma IL-22 level did not correlate with the number of circulating Th17 cells, suggesting that the source of IL-22 are both Th22 and Th17, with the share of Th17 in the plasma pool being small [28]. This evidence concerns the gene CD4 and preeclampsia.