Provided herein is a method of monitoring the change of the alpha-4 integrin activities in an individual by correlating with the soluble vascular cell adhesion molecule (sVCAM) and/or soluble mucosal addressin cell adhesion molecule (sMAdCAM) levels. Particularly, this method can be used, for example, to evaluate the pharmacokinetics and pharmacodynamics (PK/PD) of an alpha-4 integrin inhibitor used to treat a disease associated with pathological or chronic inflammation.