TY - JOUR T1 - Noninvasive Imaging of Human Immune Responses in a Human Xenograft Model of Graft-Versus-Host Disease JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1003 LP - 1008 DO - 10.2967/jnumed.116.186007 VL - 58 IS - 6 AU - Catharina H.M.J. Van Elssen AU - Mohammad Rashidian AU - Vladimir Vrbanac AU - Kai W. Wucherpfennig AU - Zeina el Habre AU - Jana Sticht AU - Christian Freund AU - Johanne T. Jacobsen AU - Juanjo Cragnolini AU - Jessica Ingram AU - Loes Plaisier AU - Eric Spierings AU - Andrew M. Tager AU - Hidde L. Ploegh Y1 - 2017/06/01 UR - http://jnm.snmjournals.org/content/58/6/1003.abstract N2 - The immune system plays a crucial role in many diseases. Activation or suppression of immunity is often related to clinical outcome. Methods to explore the dynamics of immune responses are important to elucidate their role in conditions characterized by inflammation, such as infectious disease, cancer, or autoimmunity. Immuno-PET is a noninvasive method by which disease and immune cell infiltration can be explored simultaneously. Using radiolabeled antibodies or fragments derived from them, it is possible to image disease-specific antigens and immune cell subsets. Methods: We developed a method to noninvasively image human immune responses in a relevant humanized mouse model. We generated a camelid-derived single-domain antibody specific for human class II major histocompatibility complex products and used it to noninvasively image human immune cell reconstitution in nonobese diabetic severe combined immune deficiency γ−/− mice reconstituted with human fetal thymus, liver, and liver-derived hematopoietic stem cells (BLT mice). Results: We showed imaging of infiltrating immunocytes in BLT mice that spontaneously developed a graft-versus-host–like condition, characterized by alopecia and blepharitis. In diseased animals, we showed an increased PET signal in the liver, attributable to infiltration of activated class II major histocompatibility complex+ T cells. Conclusion: Noninvasive imaging of immune infiltration and activation could thus be of importance for diagnosis and evaluation of treatment of graft-versus-host disease and holds promise for other diseases characterized by inflammation. ER -