a strong trendP = 0.07
At 14 d after immunization, confocal microscopy confirmed the localization of CXCR5-deficient T FH cells to the dark zone and a strong trend ( P = 0.07) towards a diminished FDC network in Cxcr5 fl/fl ; Cd4 ERT2Cre mice compared with Cxcr5 +/+ ; Cd4 ERT2Cre controls (Extended Data Fig. 9 ).