Expression of homing markers on Tregs in PB and BM differs from those of Tregs in secondary lymphoid organs. Flow cytometry of homing marker expression on CD4^posCD25^pos Tregs form human PB, BM, liLNs, inLNs, and SPL samples. Percentages of CD4^posCD25^pos Treg positive for indicated markers are shown (N = 4-8 for each tissue). Data were analyzed using a random-effect logistic regression model. Significant differences are indicated: *P < .05; **P < .01; ***P < .001.