Biomarkers (e.g. cytokines) that are commonly measured to assess the immunomodulatory effects of nano- or micro-particulates may be adsorbed on their surfaces and/or absorbed within internal regions, thereby, generating an inaccurately low measure of immunotoxic effect. We provide this commentary, therefore, as a cautionary recommendation that previously published data be reassessed, and future investigations consider potential artifacts and data misinterpretation carefully. (C) 2018 Elsevier Ltd. All rights reserved.