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  • [Proc Natl Acad Sci U S A.] Detection of immune responses after immunotherapy in glioblastoma using PET and MRI.

    David Geffen School of Medicine at UCLA / Micheal E. Phelps*, Robert M. Prins*

  • 출처
    Proc Natl Acad Sci U S A.
  • 등재일
    2017 Sep 19
  • 저널이슈번호
    114(38):10220-10225. doi: 10.1073/pnas.1706689114. Epub 2017 Sep 5.
  • 내용

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    Abstract

    Contrast-enhanced MRI is typically used to follow treatment response and progression in patients with glioblastoma (GBM). However, differentiating tumor progression from pseudoprogression remains a clinical dilemma largely unmitigated by current advances in imaging techniques. Noninvasive imaging techniques capable of distinguishing these two conditions could play an important role in the clinical management of patients with GBM and other brain malignancies. We hypothesized that PET probes for deoxycytidine kinase (dCK) could be used to differentiate immune inflammatory responses from other sources of contrast-enhancement on MRI. Orthotopic malignant gliomas were established in syngeneic immunocompetent mice and then treated with dendritic cell (DC) vaccination and/or PD-1 mAb blockade. Mice were then imaged with [18F]-FAC PET/CT and MRI with i.v. contrast. The ratio of contrast enhancement on MRI to normalized PET probe uptake, which we term the immunotherapeutic response index, delineated specific regions of immune inflammatory activity. On postmortem examination, FACS-based enumeration of intracranial tumor-infiltrating lymphocytes directly correlated with quantitative [18F]-FAC PET probe uptake. Three patients with GBM undergoing treatment with tumor lysate-pulsed DC vaccination and PD-1 mAb blockade were also imaged before and after therapy using MRI and a clinical PET probe for dCK. Unlike in mice, [18F]-FAC is rapidly catabolized in humans; thus, we used another dCK PET probe, [18F]-clofarabine ([18F]-CFA), that may be more clinically relevant. Enhanced [18F]-CFA PET probe accumulation was identified in tumor and secondary lymphoid organs after immunotherapy. Our findings identify a noninvasive modality capable of imaging the host antitumor immune response against intracranial tumors.

     

    Author information

    Antonios JP1, Soto H1, Everson RG1, Moughon DL1, Wang AC1, Orpilla J1, Radu C2,3,4, Ellingson BM3,5, Lee JT2,4, Cloughesy T3,6, Phelps ME7,3,4, Czernin J2,3,4, Liau LM1,3,8, Prins RM9,2,3,8.

    Department of Neurosurgery, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095.

    Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095.

    Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095.

    The Crump Institute for Molecular Imaging, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095.

    Department of Radiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095.

    Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095.

    Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095; mphelps@mednet.ucla.edu rprins@mednet.ucla.edu.

    Brain Research Institute, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095.

    Department of Neurosurgery, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095; mphelps@mednet.ucla.edu rprins@mednet.ucla.edu. 

  • 키워드
    MRI; PET; checkpoint blockade; glioblastoma; immunotherapy​
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